DEV Community: RUNESKEE

CMCU-08: A Multi-Channel Strain Gauge Transmitter for Industrial Data Acquisition

RUNESKEE — Tue, 18 Aug 2026 06:51:08 +0000

1.Introduction

The CMCU-08 is an industrial-grade 5-channel and 12-channel strain gauge transmitter launched by Shenzhen RunesKee Technology Co., Ltd. It supports single-bridge, half-bridge, and full-bridge configurations. Compact, easy to use, stable, and reliable in performance, it can simultaneously collect data from multiple resistance strain gauges, with sampling rates of 10Hz, 40Hz, 640Hz, and 1.28KHz. It connects to a computer via a single USB interface and also supports communication with devices/PLCs/computers through an RS485 serial port.

Features include:

USB power supply range: 5V;
RS485 interface power supply range: DC 7-28V;
Operating temperature: -40℃ to 85℃;
Communication interfaces: USB and RS485 serial communication;
Sampling channels: 5-channel/12-channel;
Communication format: Baud rate 115200 (adjustable), 8 data bits, 1 stop bit, no parity;
Communication protocol: MODBUS-RTU protocol, supporting function codes: 03, 06, 16 (0x10);
AD precision: 24-bit;
Resolution: 1/50,000 division;
Address range: 1-247, default is 1;
Sampling frequency: 10Hz, 40Hz, 640Hz, 1.28KHz;
Screen size: 2.0-inch 320*240 TFT color display;
Configurable parameters include division value, baud rate, zero-tracking range, zero-tracking enable, average filtering, creep tracking range, etc., making it suitable for most applications.

2.Hardware Specifications

2.1 Hardware Parameters

2.2 Hardware Resource Overview

2.3 Hardware Dimensions

3.Setting Up the Test Hardware Environment

3.1 Connecting Strain Gauges to the CMCU-08 Transmitter

3.2 Method 1: Connect to a computer using just a USB cable

3.3 Method 2: Connect to a computer using the RS485 interface

3.4 Method 3: Use with a wireless transparent transmission kit for wireless communication

3.5 Method 4: Pair with an RS485 4G module for IoT cloud connectivity

4.Appendix 1: Example Connections for Strain Gauge Transmitters

5.Appendix 2: Applications of Strain Gauge with Different Structures

🌿🌿🌿 Check our website : www.runeskee.com

Scissor Blade Shear Stress-Strain Measurement Based on Strain Gauges

RUNESKEE — Tue, 18 Aug 2026 06:24:23 +0000

1. Overview of the Solution
Scissors are a common tool in our daily lives. Their principle is actually quite simple - they are levers. By gripping the handle and applying force, the power is transmitted through the pivot to the blades, completing the cutting action. However, in actual operation, whether a pair of scissors is "sharp" or "comfortable to use" can mostly only be judged by experience and feel.

We attach tiny sensors called "strain gauges" onto the scissor blades. When the scissors are subjected to force, the blades undergo extremely small deformations, which are then converted into electrical signals. This allows the forces acting on the scissors during operation to be recorded in real-time and quantitatively.

This principle is not only applicable to ordinary scissors. For example, medical instruments such as surgical forceps and bone rongeurs also need to clarify the relationship between "how much force is applied by the hand" and "how much force is exerted at the jaw" in order to optimize design, improve feel, or be applied in the field of intelligent robotics. In industry, force monitoring of tools like wire crimping pliers and rebar cutters is related to product quality and operational safety. This measurement method can be applied to everything from determining tool wear to ergonomic evaluation.

This solution uses the CMCU-08A multi-channel strain gauge transmitter launched by RunesKee for demonstration. Taking an ordinary pair of scissors as the object, six strain gauges are attached to the surface of the blades (three on each blade) to perform real-time measurement and analysis of the forces during the cutting process. The measurement accuracy is 24-bit AD, and the minimum measurement resolution can reach 0.1με ‌. More importantly, it can be connected to a computer with a single USB cable for synchronous data acquisition, data saving, and using the data screen recording playback function. It can also be paired with an RS485 wireless transmission kit to achieve wireless data transmission, eliminating the constraint of cables, which offers high flexibility for the scissor operation measurement environment. We hope that the method established by this solution can also provide some reference for similar applications such as medical instruments, industrial tools, and even tool health monitoring.

2. Measurement Solution
2.1 Composition of the Measurement System
The measurement system consists of the following parts:

2.2 Strain Gauge Attachment Locations
The selection of strain gauge attachment locations is a critical step in the measurement. The approach adopted this time: attach the strain gauges to the surface of the two scissor blades, selecting three measurement points to analyze the deformation of each part of the scissors during operation separately. Before attachment, the bonding surface needs to be sanded (if the surface is smooth and flat, this step can be skipped) and cleaned to remove the oxide layer and oil stains, ensuring close contact between the strain gauge and the blade surface. After attachment, it is necessary to apply pressure with a finger for curing, and then wait for the adhesive to fully cure before proceeding with the experiment.

According to the requirements of the experiment, this is a short-term experiment with an ambient temperature of about 28~30°C. Ordinary 502 adhesive glue was used for testing, with finger pressing for curing for one minute. For ultra-short-term experiments, the test can be conducted after leaving it for more than 20 minutes. It is recommended to leave it to stand for 1 hour (full curing).

If conducting long-term monitoring experiments, professional glue must be used. Generally, there is room-temperature curing AB glue, and more professionally, H610 epoxy resin AB glue.

3. Experiment Process
3.1 Experiment Preparation

Select a standard pair of scissors, clean the upper surface of the blade arms, and attach the strain gauges at the predetermined positions.
Connect the strain gauge lead wires to the sensor interface of the CMCU-08A acquisition board.
Connect the acquisition board to the computer via a USB cable, open the debugging software to set the strain gauge parameters, and then start data acquisition. Additionally, a data analysis software is also provided.

3.2 Experiment Design
Experiment 1: Comparative Measurement of Empty Cutting and Actual Cutting
By comparing the strain signal differences between "empty cutting" (cutting nothing) and "actual cutting," the force used purely for material fracture is isolated. Specific operation: First, perform empty cutting with the same pair of scissors and record the strain signal (mainly reflecting the blade arm's own movement and pivot friction). Then, cut the standard test material and record the strain signal during actual cutting. The difference between the two is the effective force used to cut the material, which serves as a quantitative indicator for evaluating scissors sharpness.

Experiment 2: Comparison of Shear Forces for Different Materials
Select objects of different materials and thicknesses such as paper, thick cardboard, PVC plastic sheet, and cables. Conduct shear experiments separately, recording the strain-time curve during the cutting of each material. By performing shear experiments on different samples, materials with different mechanical properties can be distinguished. (Since it is a manual experiment, the cutting force and angle are difficult to control, so the data may vary. However, this does not affect the principle of this shear experiment.)

Extended Experiment: Trend of Force Variation in Repeated Cutting
Continuously cut the same standard material multiple times (e.g., 50 or 100 times), recording the peak strain for each cut. Observe the trend of the peak force as the number of cuts increases - if the force continues to increase, it indicates gradual wear of the blade edge.

Alternatively, after cutting sticky tape multiple times, the adhesive residue sticks to the blade edge, making it increasingly dull. The required cutting force will also increase. Through these data phenomena, abnormal conditions of the blade edge can be identified, allowing for timely cleaning.

3.3 Data Acquisition
The AD chip sampling rate of the CMCU-08A collector supports 10Hz, 40Hz, 640Hz, and 1.28KHz (The chip sampling frequency is not the serial port acquisition rate), with a communication baud rate of 115200 (adjustable). When communicating with a computer, due to limitations of the computer's serial port environment, the fastest acquisition interval can reach 10ms per sample. If connected to an industrial control device, the fastest acquisition interval can reach 5ms per sample.

For transient processes such as scissor cutting, the aim is to capture the stress peak and dynamic changes at the moment of cutting. The experimental setup used in the literature "Force Sensing Surgical Scissor Blades using Fibre Bragg Grating Sensors" has also been verified to accurately distinguish homogeneous tissue samples, demonstrating the potential of this method in material identification.

4. Application Value
4.1 Comprehensive Evaluation of Scissor Performance
This solution measures the force on the scissor arm using strain gauges, serving the evaluation of scissor performance at three levels simultaneously. For sharpness quantification, the pure shear force required to cut through the material is calculated from the difference in strain signals between "empty cutting" and "actual cutting." This value directly reflects the sharpness of the blade edge and can serve as an objective standard for factory inspection, replacing subjective "trial cutting." For material identification, different materials exhibit distinct force-time curve characteristics during the cutting process, which can be used to analyze the mechanical properties of the cut material. For wear monitoring, by repeatedly cutting the same material and tracking changes in peak force, when the peak force exceeds a certain percentage of the initial value, it can be determined that sharpening or replacement is needed, enabling predictive maintenance.

4.2 Medical Device Field (Surgical Forceps/Needle Holders/Bone Rongeurs)
Surgical forceps, needle holders, bone rongeurs, and other instruments share the same mechanical structure as scissors - centered on a pivot shaft, with handle input and jaw output. By attaching strain gauges near the jaws, the interaction force between the instrument and the tissue can be measured. During the development phase, comparing the measured jaw force with the handle force allows for evaluating the instrument's transmission efficiency and tactile feedback. Taking bone rongeurs as an example, measuring the force on the jaws when breaking bone ensures that the doctor can obtain sufficient clamping force with minimal hand effort, avoiding slippage during surgery (insufficient force) or tissue damage from clamping (excessive force). This method can also be used for comparative evaluation of similar products from different brands, as well as for assessing performance degradation of the same instrument after repeated use.

4.3 Industrial Crimping and Cutting Tools (Wire Harness Crimping Pliers/Cable Cutters)
In aerospace and automotive wiring harness factories, crimping pliers and cable cutters are used at high frequency daily, and their working quality directly determines product reliability. The force on the jaw of the crimping pliers directly reflects the tightness of the crimped terminal - too little force can lead to excessive contact resistance (a risk of overheating), while too much force may crush the core wire. By using strain gauges to monitor the peak force of each crimp, and prompting mold replacement when the peak force continuously decreases, batch quality incidents can be prevented. The force monitoring on the blade edge of cable cutters is used to determine whether the blade has become dull or whether the cable has been completely cut, avoiding burrs or core wire damage caused by incomplete cutting. This method is also applicable for assessing operator fatigue - if a worker's handle force on the same tool is consistently high, it indicates issues with operating posture or tool maintenance.

4.4 Agricultural and Horticultural Pruning Tools (Pole Pruners/Heavy-Duty Fruit Shears)
Pole pruners achieve remote operation through pulley systems or linkage mechanisms, with the core design principle being the force-saving ratio. By attaching strain gauges to the base of the blade to measure the force during branch cutting, the actual force-saving ratio can be directly verified against the design target. If the measured cutting force is higher than the theoretical value, it indicates excessive friction loss in the pulleys or jamming in the linkage hinges, requiring design optimization. In practical use, fruit farmers and gardeners often rely on feel to judge whether shears need sharpening. This solution provides a quantitative basis - if the peak force for cutting the same type of branch increases by a certain amount compared to initial use, the blade has become dull and needs sharpening. For large orchards, this means maintenance guidance can be provided remotely without disassembly.

4.5 Robot Flexible Grippers
When industrial grippers or bionic hands grasp precision parts (such as eggs or chips), precise control of the gripping force is required. By attaching strain gauges to the fingertips or gripper arms, the gripping force on the object can be measured in real time. This measurement principle is the same as that for measuring force on scissors - scissors involve "human holding the handle → blade outputting cutting force," while grippers involve "actuator inputting torque → fingertip outputting gripping force." By monitoring changes in gripping force in real time, the controller can dynamically adjust the drive current, achieving "compliant control" and preventing the object from being crushed.

5. Application Prospects
5.1 Smart Surgical Instruments
With the increasing popularity of minimally invasive surgery and robotic surgery, the demand for smart surgical instruments with force sensing capabilities is growing. The strain gauges used in this solution are small in size and low in cost, and are expected to serve as force-sensing components for surgical scissors, forceps, and other instruments, providing surgeons with real-time force feedback and enhancing surgical safety.

5.2 Health Monitoring of In-Service Cutting Tools
The tool force monitoring system based on strain measurement can be integrated with the IoT platform to achieve automatic warning and life prediction of tool wear. When the shear force continues to increase and exceeds the set threshold, the system automatically prompts tool replacement, which is especially suitable for manufacturing production lines that use molds and tools in batches.

5.3 Mechanical Properties Testing of Materials
Using sensorized blades to measure the force-time curve during material shearing provides a simple, low-cost new method for fracture toughness testing of biological tissues, soft materials, etc., and can serve as a supplementary solution to traditional material testing machines.

5.4 Ergonomics and Labor Safety
Through long-term accumulation of tool operation force data, a database of operation forces for different types of work can be established, providing data support for the formulation of labor safety standards and the design of labor-saving tools.

6. Summary
This paper proposes a set of experimental schemes for stress measurement of scissor arms based on strain gauges and the CMCU-08A strain acquisition unit. By pasting strain gauges on the surface of scissor arms and calibrating the relationship between strain and force, real-time measurement and quantitative analysis of the force on the blade during shearing are achieved.

For the first measurement of a particular style or material of scissors, for the sake of rigor, it is recommended for large scissors to paste strain gauges in sections and first measure whether the force in each area is consistent. If the measurement results are satisfactory, only one strain gauge at one location can be selected for use, eliminating the need for multiple strain gauges. For small scissors, generally one strain gauge is sufficient, pasted on a limited area of the blade or arm.

The core value of this scheme lies in providing a quantitative means for evaluating scissor sharpness, identifying material mechanical properties, and monitoring tool wear. The measurement approach can be extended to fields such as medical devices, industrial crimping and cutting tools, agricultural and forestry pruning tools, and robot grippers, offering technical references for the performance evaluation and condition monitoring of related tools.

🌿🌿🌿 Check our website : www.runeskee.com

Principles, Selection, and Usage Guide for Resistance Strain Gauges

RUNESKEE — Tue, 18 Aug 2026 06:04:39 +0000

1. What is Microstrain (με)? What are the Unit and Symbol of Microstrain?
Strain refers to the local relative deformation of an object under the combined effects of external forces, temperature changes, and other factors. It is the amount of deformation per unit length, and its formula is as follows:
ε = ΔL / L
Assuming the length of a structure is L, and after being deformed by force, its length becomes L', then the change in length is ΔL = L' - L. The strain (denoted by ε) is the ratio of the change ΔL to the original length L. As can be seen from the formula, strain is a ratio, which is dimensionless, meaning it has no unit.

So what is microstrain? Since ΔL is very small, typically on the order of micrometers, the calculated strain value is also very small, with many digits after the decimal point, making it inconvenient to display and read. Therefore, the scientific notation 10–6 is introduced, which is called microstrain, denoted by the symbol με. It can be understood that the unit of microstrain is 10–6, so the value of microstrain is magnified by one million times compared to the strain value, resulting in an integer. The measurement range of our strain gauge is ±1500 microstrains, where positive indicates tension and negative indicates compression.
1ε = 106με

2. Principle of Resistance Strain Gauges:
Metal materials inherently possess a specific resistance value. Therefore, when subjected to external tension (or compression), i.e., stretching (or shortening), their resistance value increases (or decreases) accordingly. When a metal material experiences strain, assuming the resistance R changes by ΔR under this influence, the following equation holds true.

Ks is called the strain factor, a constant indicating the sensitivity of the strain gauge. The strain sensitivity coefficient for general strain gauges made of copper-nickel alloy and nickel-chromium alloy is approximately 2, with a typical range of (2.0~2.2).

3. Structure of Resistance Strain Gauges:

Use a specialized adhesive to bond the strain gauge to the measurement location. The strain generated at the measurement location is transmitted to the sensitive grid through the adhesive and the base of the strain gauge. To accurately measure strain, the selected strain gauge and adhesive must satisfy the usage conditions, such as the measurement material and operating temperature. For the method of bonding strain gauges to metal, please refer to the strain gauge bonding procedure and moisture-proof treatment.

4. Selection of Strain Gauge Structure Type

In the fields of mechanical measurement and sensor design, strain gauges are one of the most widely used core sensitive elements. Whether for structural stress analysis, material property testing, or the manufacture of various force sensors and load cells, strain gauges are indispensable. However, faced with the dazzling array of strain gauge models available on the market - such as the BF120, BF350 series, and BA series - many users encountering them for the first time often feel confused: What do the numbers and letters in the model numbers signify? What is the difference between 120Ω and 350Ω strain gauges? Should the grid length be 1mm or 3mm? This article systematically outlines the key parameters and decision-making ideas for selecting strain gauges, helping you choose the most suitable one.

4.1. The determination of strain gauge type is primarily based on the dimensional characteristics of the measured stress field and the knowability of the principal stress direction.

(Uniaxial strain gauge, AA series)
For conditions involving a one-dimensional stress state with a known principal stress direction - such as axial tension rods or pure bending beams - uniaxial metal foil or wire strain gauges are the preferred solution. This type of scenario accounts for the highest proportion of engineering stress analysis, offering mature technology and controllable implementation costs.

(Biaxial strain rosette, BA series)
Under a plane stress state, if the principal stress direction is known, a right-angle strain rosette (biaxial) should be used. During installation, ensure that one of the sensitive grids is strictly aligned with the principal stress direction to obtain the most direct strain-stress conversion relationship.

(Triaxial strain rosette, CA series)
When the principal stress direction is unknown, a three-grid or four-grid strain rosette should be adopted. By obtaining multi-directional strain data from a single application, the magnitude and direction of the principal stress can be calculated using the strain rosette formula, avoiding the efficiency loss and error accumulation caused by repeated trial applications.

4.2. In the field of strain-type sensors, the type selection must match the loading mode of the elastic element:

Elastic elements primarily subjected to tensile/compressive or bending stresses, such as column, beam, and ring types, all use uniaxial strain gauges;
Elastic elements targeting shear stress measurement (e.g., torque sensors) use biaxial strain rosettes arranged at a 45° angle. From the perspective of material and process, metal foil strain gauges have become the mainstream choice for current engineering applications due to their dimensional accuracy, line uniformity, and shape customizability offered by photolithography and etching processes. Their minimum sensitive grid length can reach 0.2 mm, and their bonding performance, heat dissipation capability, and transverse effect suppression are all superior to those of wire-type structures. Metal wire strain gauges are now mainly retained for special high-temperature custom scenarios, while metal thin-film strain gauges, limited by process costs, are only applied in specific high-precision or extreme temperature situations.

5. Selection of Materials

The determination of the sensitive grid material is primarily constrained by the operating temperature range. This parameter is non-negotiable - insufficient temperature resistance of the material will directly lead to strain gauge failure or performance drift.

Room temperature strain gauges (-30°C to 80°C): Constantan is the industry standard choice. Its strain sensitivity coefficient is approximately 2.0, with a low temperature coefficient of resistance, mature process technology, stable supply chain, and reasonable cost structure.

At the backing material level, the current mainstream choice is adhesive-based materials, including special fibers, epoxy resin, phenolic resin, and polyimide, with a typical thickness of 0.03 to 0.07 mm. The backing must simultaneously meet requirements for mechanical strength, flexibility, adhesion, electrical insulation, moisture resistance, and must be free of mechanical hysteresis and creep.

6. Selection of Resistance Value
The standard resistance series includes 120Ω, 350Ω, and 1000Ω. In engineering practice, 120Ω and 350Ω are dominant, and their selection logic is as follows:

When using a resistance strain indicator for stress analysis, 120Ω is the standard matching resistance. This specification is compatible with the bridge circuit design of mainstream strain indicators and can be directly connected without additional impedance matching.

In the development of strain gauge sensors, 350Ω is the recommended specification. Its advantages include: allowing a higher operating voltage, correspondingly improving output sensitivity; a lower operating current, reducing temperature rise caused by self-heating, which benefits long-term stability; and a better signal-to-noise ratio in dynamic measurement scenarios. Currently, the sensor industry shows a clear trend towards higher resistance values. When long cables are subsequently connected, higher resistance offers better anti-interference, but the bridge excitation voltage is limited by the amplifier's input range.

Typical excitation voltage range (e.g., 5~10V is common for 350Ω, and 2~5V for 120Ω), the excitation current is usually controlled within ‌ 10～15mA ‌ (the limit can reach 30mA on materials with good heat dissipation).
When physical space and circuit conditions permit, higher resistance values should be preferred. An increase in resistance will simultaneously raise the allowable operating voltage and output voltage, thereby increasing sensitivity, while reducing the operating current and thermal effects, which positively contributes to measurement accuracy.

7. Size Selection: Balancing Spatial Resolution and Averaging Effect

The determination of the sensitive grid length (base length) requires comprehensive consideration of stress gradient, material uniformity, and dynamic response requirements.

For areas with uniform specimen material and significant stress gradients - such as stress concentration zones and notch roots - a small grid length (0.2mm to 3mm) should be selected. A shorter grid length improves spatial resolution, allowing more accurate capture of local strain extremes.

For non-uniform materials (such as concrete) or components with gentle stress distribution, a larger grid length (3mm to 100mm) is recommended. A longer grid length produces an averaging effect, making the measurement results more representative of the overall strain level in the area, thus avoiding data dispersion caused by local material differences.

In impact load or high-frequency dynamic measurement scenarios, the sensitive grid length should be minimized as much as possible. Grid length is inversely correlated with the upper measurable frequency limit; shortening the grid length effectively improves dynamic response capability, ensuring that the measurement signal truly reflects the measured strain time history.

Reference for common engineering specifications: The minimum grid length for foil strain gauges is 0.2mm, suitable for precision measurements; general stress analysis primarily uses 1mm to 3mm; for sensor applications, the grid length is matched according to the size of the elastic element's stress zone, with a common range of 1mm to 5mm.

8. Strain Gauge Bonding Process and Protection
The performance of a resistance strain gauge depends not only on the quality of the gauge itself but also on its correct usage. For commonly used bonded strain gauges, the bonding process is a critical step. The following are the key steps and points summarized:

Common problems after bonding:

Abnormal resistance value
Under normal circumstances, the resistance value of the strain gauge remains unchanged or changes slightly after bonding. If the resistance value changes significantly, it may be caused by the following factors:

Excessive pressure during pressure curing leads to abnormal resistance after bonding; reduce the pressure appropriately;
Uneven pressure during curing causes deformation of the strain gauge's sensitive grid and abnormal resistance. This issue is mainly due to non-standard pressure fixtures, resulting in uneven stress on the strain gauge;
The curvature radius of the fixture design does not match the component, causing deformation or bulging of the strain gauge and abnormal resistance;
If the resistance becomes abnormal after a period of use, the main reasons include bubbles inside the strain gauge, individual voids, or unreliable factors during welding;
If the resistance remains abnormal after multiple attempts, check whether the multimeter is faulty.

Major defects
The main defects in bonding include voids, bulging (abnormal bridge zero), uneven adhesive layer (strain gauge detachment), excessively thick adhesive layer (poor sensor creep), adhesive ridges, pressure pits, and misalignment (actual strain gauge value smaller than the true value). To address these defects, a visual inspection must be performed after bonding to eliminate defective ones and ensure bonding quality. At the same time, the resistance value and insulation resistance should be checked to avoid waste in subsequent processes.

Wire connection
Check whether the welding is reliable and whether there is any risk of short circuits. Avoid contact resistance.
Resistance strain gauge, Strain measurement, Microstrain, Sensor selection, Stress analysis, Strain, Bonding process, Mechanical testing, Experimental mechanics, Sensor design, Strain indicator, Mechanics of materials, Piezoresistive effect, Industrial measurement.

🌿🌿🌿 Check our website : www.runeskee.com

Giving a Robotic Hand a Sense of Touch: Building a Five-Finger Data Acquisition and Feedback System from Scratch

RUNESKEE — Mon, 17 Aug 2026 11:16:07 +0000

If you've played with a humanoid robot or watched related robot review videos, you must be familiar with this scenario:

A high-end robotic hand worth tens of thousands of yuan can precisely perform fixed actions like grabbing a can or crushing a paper cup, but throughout the process, it has absolutely no idea how much force its fingers are exerting. All actions are predefined open-loop commands, without perception or feedback. It's like a strong man with no sense of touch, prone to problems such as crushing objects or dropping items during grasping.

The core of a truly dexterous biomimetic hand device lies in its perception capability.

Whether it's a rehabilitation exoskeleton robot recognizing the patient's intended movement, a teleoperated robot achieving human-machine force interaction feedback, or a smart glove for gesture control, fingertip pressure data and finger joint bending angle data are the most fundamental and indispensable core signal inputs for all smart hand devices.

This project avoids expensive industry solutions: no costly ATI industrial six-axis force sensors, and no complex multi-finger array tactile skins. It builds a five-finger hand perception system from scratch using modular, low-cost, general-purpose sensors.

I. System Architecture
The entire hand five-finger acquisition and feedback system is divided into three main modules: the perception layer, the processing layer, and the feedback layer, comprehensively covering the entire process of signal acquisition, data processing, and closed-loop feedback.

(A) Perception Layer: Installing Bionic Nerve Endings on the Robotic Fingers

The perception layer is the signal source of the system. It consists of two hardware units: fingertip pressure acquisition and joint bending acquisition, corresponding to tactile perception and posture perception. The hardware selection meets the flexible wearable requirements of the human hand without restricting finger movement.

Fingertip Tactile Acquisition (Pressure Detection)
Selection: 5x RP-C7.6-ST-LF Thin Film Pressure Sensors
Working Principle: The sensors are attached to the pads of the five fingers. The force and resistance are inversely correlated. The greater the gripping pressure applied by the finger, the smaller the internal contact resistance of the sensor. The real-time force on the fingertip is reconstructed based on the change in resistance.
Joint Bending Acquisition (Angle Detection)
Selection: 5 pcs 350–30AA single-bridge strain gauges (choose the appropriate length of single-bridge strain gauges based on the joint dimensions of the robotic hand fingers)
Working Principle: The strain gauge is attached to a resilient elastic element (which can be an elastic plastic film, spring steel sheet, composite material, etc.), placed at the movable joint of each finger. When the finger bends, it drives the elastic element, stretching the sensitive grid wires of the strain gauge, causing the resistance to increase; when the finger straightens, the resistance recovers
Key Difficulty Explanation: The resistance change caused by strain gauge deformation is only at the milliohm level, making the signal extremely weak. It cannot be directly collected by a microcontroller and requires a dedicated acquisition device for signal amplification.

(B) Processing Layer: Amplify weak signals to make hand data visually observable

Given the signal differences between the two types of sensors, a dual-collector parallel acquisition scheme is adopted. Pressure signals and angle signals are transmitted independently, paired with host computer software to achieve dynamic curve visualization.

Processing Fingertip Pressure Signals: CMCU-05B Multi-Channel Thin Film Pressure Collector:
Wiring Method: 5-way thin film pressure sensors are directly connected to the device's acquisition channels. The sensors have no positive or negative polarity distinction, making it beginner-friendly for wiring.
Hardware Functions: Built-in voltage divider circuit + signal amplification circuit converts the analog resistance signal into a standard voltage signal. It is equipped with a 16-bit high-precision ADC for digital quantization.
Local Display: The device features a 2.0-inch high-definition color screen, supports free switching between multiple units such as g/kg/N, and displays pressure values and pressure curves in real time.
Host Computer Communication: Supports USB/TTL serial port, communicates with the computer via the MODBUS-RTU standard protocol, enabling synchronized pressure data collection, free calibration, parameter modification, and other settings. Processing Joint Bending Signals: (Wireless single-channel one-to-five scheme or wired 5-channel scheme)

CMCU-09A Wireless Single-Channel Strain Collector, or choose the CMCU-08A Five-Channel Strain Collector.

Wiring Mode: The strain gauge is connected to the collector using a 1/4 bridge configuration.
Hardware Functions: Amplifies millivolt-level weak differential signals, built-in bridge algorithm converts and processes the electrical signal from the strain gauge while filtering out environmental electrical noise.
Data Calibration: After software calibration of the original electrical signal, it is directly mapped to a standard finger bending angle of 0°-180°
Host Computer Software Visualization The two data streams are transmitted independently to the computer. By opening the accompanying host computer software, you can simultaneously view the pressure change curves of 5 fingertips and the bending angle change curves of 5 finger joints. Communication with microcontrollers and industrial control devices via serial port allows the robot's main controller to collect and process the data.

Feedback Layer: Build a system conditioned reflex to achieve tactile closed-loop interaction

Move beyond mere data collection by adding a hardware feedback module, achieving a complete closed loop of "Hand motion capture → System automatic judgment → Hardware feedback response".

Trigger logic: set a fingertip pressure threshold on the acquisition device, and when the hand gripping force exceeds the threshold;
Feedback method: the device I/O port automatically outputs a high-level signal, which can quickly light up the LED indicator with a relay;
Expansion reserved: this implementation only achieves visual light feedback, with hardware reserved external interfaces. Subsequent upgrades can directly add vibration motors and buzzers to upgrade to real vibration tactile feedback.

II. Practical demonstration: gripping a glass
To intuitively verify the synchronous acquisition performance of the entire system, we conducted a real-world gripping test using an everyday glass. The complete test video: https://www.bilibili.com/video/BV1gx4y187dv/?spm_id_from=333.1387.upload.video_card.click

Observed phenomena during the actual test

Fingers naturally open: all 5 pressure curves return to zero, all joint bending angles return to zero, and the indicator light turns off;
Hand slowly grips the cup: all five finger joints bend simultaneously, angle curves rise synchronously; fingertips contact the cup wall and bear force, five pressure curves rise in sequence;
Continuous firm grip on the cup: pressure reaches the preset threshold, and the onboard LED indicator lights up synchronously;
Release the cup: fingertip pressure quickly drops back to zero, finger joints reset, angle curves decrease synchronously, and the indicator light turns off accordingly.

Test conclusion: the pressure data, joint angle data, and human hand movements are fully synchronized, with no delay and no data drift, accurately reproducing every subtle gripping action and force exertion of the human hand.

III. Application value

Lightweight wearable smart glove development for the human body
All sensors are flexible ultra-thin devices that can be directly attached to the skin of the hand without the need for bulky mechanical shells, enabling rapid and low-cost development of wearable smart sensing gloves. Compared with commercial thousand-yuan-level smart gloves on the market, the overall hardware cost of this solution is reduced by over 70%, allowing for all-day monitoring of hand movement posture and fingertip force data, suitable for the development of wearable devices such as gesture peripheral control and human hand motion capture.
Tactile empowerment for bionic robotic hands
Directly collect standard raw data of human hand gripping and touching, replicating the human force application logic and bending posture onto the bionic robotic hand. Solve industry pain points such as uncontrollable force in traditional open-loop robotic hands, crushing of fragile objects, and object detachment during grasping, filling the tactile gap in industrial robotic hands, and creating a truly perceptive dexterous robotic hand.
VR/AR virtual human-machine interaction
An affordable alternative to commercial-grade motion capture gloves costing tens of thousands of yuan, it simultaneously captures dual data: finger bending posture and real fingertip pressure. It compensates for the shortcomings of traditional motion capture devices, which only capture motion without force feedback, enabling realistic touch, pinch, and grip interactions in virtual scenes, greatly enhancing the immersion of virtual reality interactions.
Hand Rehabilitation Medical Training
Targeting hand dysfunction after stroke and hand trauma patients undergoing post-surgery rehabilitation, it objectively and quantitatively records two core rehabilitation metrics: finger bending amplitude and fingertip force magnitude. Using visual curve data replaces the doctor's subjective visual judgment, accurately tracking the recovery progress of hand muscles and nerves, making rehabilitation training effects quantifiable and reviewable.
University Maker & Embedded Teaching Training
The project has a high degree of modularity, with the principles of pressure sensors and strain gauges being clearly independent, and the collector division of labor being clear. It is very suitable for university IoT, embedded systems, and sensor training courses. Beginners can intuitively grasp three core hardcore knowledge points: the principle of thin-film pressure sensing, strain gauge deformation angle measurement, analog signal amplification, and data visualization. Those with zero foundation can fully replicate the project.

If you've played with a humanoid robot or watched related robot review videos, you must be familiar with this scenario:
A high-end robotic hand worth tens of thousands of yuan can precisely perform fixed actions like grabbing a can or crushing a paper cup, but throughout the process, it has absolutely no idea how much force its fingers are exerting. All actions are predefined open-loop commands, without perception or feedback. It's like a strong man with no sense of touch, prone to problems such as crushing objects or dropping items during grasping.

The core of a truly dexterous biomimetic hand device lies in its perception capability.

🌿🌿🌿 Check our website : www.runeskee.com

Common Application Scenarios and Value of Thin-Film Pressure Sensors - CMCU-05B Empowers the First Step of Smart Living

RUNESKEE — Mon, 17 Aug 2026 10:44:04 +0000

In the intelligent era, data is the cornerstone of decision-making, and sensing is the starting point of data. A thin-film pressure sensor is precisely such a key "sensing layer" - it acts like a layer of thin "electronic skin", converting mechanical signals from various contact surfaces into electrical signals, giving devices a sense of touch. The role of the CMCU-05B pressure collector is to provide beginners with easy data acquisition and analysis capabilities, helping them establish a more intuitive quantitative understanding of the physical world. At the same time, it also provides technology engineers and R&D personnel with a foundational platform for data acquisition, analysis, and secondary development - through an open TTL serial communication protocol, developers can easily obtain raw data streams, perform custom algorithm development using tools like Python or MATLAB, or seamlessly integrate it into existing embedded systems to achieve a full-chain closed loop from data collection to terminal applications.

I. Product Introduction

The CMCU-05B is an industrial-grade 9-channel thin-film pressure display launched by RunesKee. It can simultaneously collect data from 9 thin-film pressure sensors or one 9-zone sensor (model RF-PUL9Z-V1), intuitively displaying the pressure distribution numerically on a 2.0-inch TFT color screen. The device supports switching between three pressure units: g, kg, and N. The sampling frequency can reach up to 1kHz. It has a built-in 450mAh battery for standalone use, and can also be connected via USB or TTL serial interface to microcontrollers or computers for data recording and analysis. It is suitable for pressure distribution testing needs in fields such as human biomechanics, rehabilitation engineering, and smart wearables. )

Key Parameters:

II. Application Scenario Testing
Scenario 1: Hand Force Distribution Test (Grip Ball Test)
Attach 6 thin-film pressure sensors to the grip ball at positions corresponding to the thumb, index finger, middle finger, ring finger, little finger, and thenar eminence (this experiment uses 6 channels, with the remaining 3 channels available for additional measurement points as needed). When the subject grips the ball, the screen displays real-time pressure values for each channel. When connected to a computer, the pressure curve can be viewed via the host computer software, allowing comparison of force changes between different grip postures or before and after rehabilitation training.

The same measurement principle can be extended to more application scenarios:

Sensors are installed on sports equipment such as baseball bats, badminton rackets, hockey sticks, etc. to analyze the grip force details of athletes' actions like holding and swinging.
Sensors installed on gloves allow smart devices to quantify abstract "feel" and provide real-time, objective feedback.
Sensors installed on VR somatosensory devices, for example, capture the details of hand force exertion and map them to the virtual world, enabling more natural interaction, such as crushing objects of different hardness based on grip strength in VR.
Grip force analysis data can provide more precise control signals for intelligent prosthetics.
Monitoring the grip strength of workers operating tools can be used to assess muscle fatigue.
In collaborative robot scenarios, grip strength sensors can perceive human intentions in real-time, enabling safer and more natural interactions.
In the aerospace field, wearable grip analysis gloves are used to quantify the hand biomechanics of astronauts in extreme environments such as extravehicular activities

Scenario 2: Plantar Pressure Distribution Test
Taking a single-foot test as an example, place 5 sensors on the insole at the root of the big toe, the front of the forefoot, the rear of the forefoot, the center of the heel, and the outside of the heel, then connect to the CMCU-05B to conduct the test. (The remaining 4 channels can be used for the opposite foot or to expand to other measurement points.)

The device can collect plantar pressure data during standing, walking, jogging, etc. The curve chart reflects the pressure waveform patterns under different gaits, providing valuable pressure distribution reference data for preliminary screening of gait abnormalities and verification of footwear design.

Plantar pressure distribution analysis, similar to grip strength analysis, is also a "window" into the body. It has long surpassed the scope of "measuring feet" and has developed into a multi-dimensional assessment tool, demonstrating irreplaceable value particularly in fields such as diabetic foot management, sports performance optimization, and footwear design

With sensors installed in insoles or inside shoes, measuring plantar pressure distribution can be applied in these scenarios:

By analyzing plantar pressure distribution, it is possible to identify high-pressure areas and predict the risk of foot ulcers.
By analyzing plantar pressure during activities like running and jumping, it is possible to detect abnormal force patterns, predict and prevent injuries such as stress fractures.
By analyzing plantar pressure characteristics under different movement patterns (e.g., running, jumping), athletes can optimize their technique, choose the most suitable shoes or insoles, and monitor training load.
Provide precise biomechanical data for sports shoes 、, elderly walking shoes 、, diabetic foot-specific shoes, etc., guiding the selection and optimization of sole structure and materials.
Provide key data for the design of orthopedic insoles and orthoses, ensuring they can effectively distribute pressure and correct gait.
By analyzing the pressure distribution between the foot and the shoe, it can help designers optimize the fit and comfort of footwear.
Used to develop smart insoles 、 and smart socks, enabling long-term, unobtrusive monitoring during daily activities.
In the control of exoskeleton robots and intelligent prosthetics, plantar pressure signals can serve as important control commands or feedback information.
Everyone's gait is unique, and plantar pressure distribution patterns can be used for biometric identification, applied to identity verification in specific scenarios.

Scenario 3: Smart Seat Pressure Distribution Test
When used in conjunction with the CMCU-05B and thin-film pressure sensors, multiple measurement points can be arranged in key areas of the cushion (centered on the bilateral ischial tuberosities, symmetrically arranged around them, and also on the backrest and armrests). After the subject sits down, the values of each channel can be read directly to quickly identify areas of high pressure concentration. This solution offers the advantages of flexible deployment and controllable costs, making it suitable for prototype validation of products such as smart home devices, automotive seats, and office health equipment.

The sensor is installed on the seat to measure seat pressure distribution, and can be applied in the following areas:

Through real-time monitoring, risk points in easily compressed areas such as the buttocks and back can be identified. By adjusting the wheelchair backrest and leg rest angles, pressure can be actively managed, and the most suitable pressure-relieving cushion for the patient can be evaluated and selected.
It provides objective sitting biomechanics data for patients such as those with spinal cord injuries, to evaluate the effect of wheelchair sitting posture adjustments on alleviating lumbar fatigue, and to guide clinical selection of special cushions that can improve spinal alignment and relieve back pain.
Smart seats integrated with sensors can monitor the sitting posture and weight distribution of patients at home, and issue early warnings when abnormalities are detected (such as prolonged sitting or abnormal center of gravity).
By analyzing pressure distribution maps, the static and dynamic comfort of seats in automobiles, offices, aviation, and other settings can be evaluated.
This data can guide engineers in adjusting filling materials, shapes, and support structures to achieve uniform pressure distribution, and to design combined seats with variable hardness that adapt to body pressure distribution.
The seat can recognize the passenger's body shape, determine the current sitting posture, and actively and automatically adjust the seat's support structure. It can even detect vital signs such as respiration and fatigue levels.
By analyzing the center of gravity and posture, more natural interaction can be achieved, such as controlling a game character based on sitting posture.
By monitoring the driver's body posture and changes in center of gravity, it is possible to determine whether they are fatigued or distracted, and issue timely warnings.
It provides data support for the design of gaming chairs, enhancing player comfort during long gaming sessions.
Smart desks and chairs can monitor students' sitting posture to help develop good habits; in office settings, they can identify fatigue states and remind employees to take timely breaks.
Develop smart seats with sitting posture monitoring and reminder functions for children, the elderly, and others.

Ⅲ. Usage Methods
Method 1: Standalone Use:
Turn on and use directly. The screen displays real-time pressure values for 9 channels, supporting unit switching among g, kg, and N.

Method 2: Connected to PC Software:

Open the data acquisition software provided by the manufacturer on the computer.
Select the corresponding COM port and click "Connect".
The main interface of the software is for pressure value acquisition. A curve chart can be opened at the top left corner.
The software features a "Data Save" function, which can save the data collected during the software process as a table file, facilitating subsequent analysis and processing.
The software supports multiple functions such as modifying configuration parameters, pressure thresholds, baud rate, adjusting the acquisition frequency, and enabling the number of channels. The collector can also be paired with a wireless transmission board to achieve remote data return, which can be applied to industrial sites where wiring is inconvenient (such as factory floors, outdoor tests, etc.).

Method 3: Connect to PLCs, touch screens, microcontrollers, and other industrial control devices via TTL serial port

The CMCU-05B provides an open TTL interface and adopts the standard MODBUS-RTU communication protocol. Data can be read and modified through corresponding register addresses. Developers only need to consult the register address table in the product manual to quickly implement data reading and writing.

This method enables the CMCU-05B to be quickly embedded into various industrial control devices, especially suitable for R&D projects that need to integrate pressure detection into their own products - such as adding pressure monitoring stations on automated production lines, or incorporating real-time force feedback functions into medical rehabilitation equipment.

Although pressure analysis appears to be a simple force test on the surface, it is actually a powerful multi-dimensional evaluation tool. From grip strength to the sole of the foot, from sitting posture to interaction, the CMCU-05B makes the data collection of thin-film pressure sensors simple, flexible, and practical - whether it's for quick verification out of the box or deep integration for secondary development, it strives to do one thing well: making the forces of the physical world perceptible, recordable, and applicable.

This data can also be used to train embodied intelligent robots - physical interaction data, The robot's world model can generate countless "what if the grip strength were different" counterfactual predictions based on this data. This essentially provides a "real anchor point" for calibrating physical parameters in the world model, greatly narrowing the gap between virtual training and real-world deployment.

🌿🌿🌿 Check our website : www.runeskee.com

Smart Home: Anti-theft Alert/Door Status Sensing Solution Based on Single-Point Thin-Film Pressure Sensing

RUNESKEE — Mon, 17 Aug 2026 10:16:32 +0000

I. Solution Overview
An ultra-thin single-point thin-film pressure sensor is selected and attached to the surface of the door handle. By collecting the grip pressure signal, the door handle status is sensed in real-time. The solution focuses on low cost and easy deployment, making it suitable for various fields such as security monitoring, smart home monitoring, and health care.

Core Device Combination:

Core Working Principle: The RP-L110 sensor is a resistive pressure-sensitive element. When no pressure is applied, the resistance is infinite. When pressure is applied, the resistance decreases as the pressure increases. The CMCU-05/05A collects the resistance change and converts it into AD values and pressure values. The wireless transparent transmission board sends the data remotely to the terminal, realizing a complete chain of "sensing - collection - transmission - recording".

Sensor Installation Position Scheme: Attached to the surface of the door handle

When a person holds the handle naturally, the thumb or the crotch of the hand contacts the upper edge area, exerting force naturally. The experimental test uses the upper edge surface, which can be attached to the inside or outside.

II. Measurement Scheme
2.1 Measurement Principle
The sensor is normally in an untriggered state (resistance > 10MΩ). When a person holds the door handle, the sensor senses pressure, and the pressure value changes. According to the pressure value, the strength of the grip can be roughly distinguished based on the force applied by the person opening the door, helping to identify the operator type (e.g., adult/child). A "door opening operation" is recorded when a pressure change is detected.

When the pressure sensed by the sensor exceeds the trigger threshold (threshold is adjustable), the CMCU-05/05A acquisition module will issue an alarm signal (the on-board threshold LED lights up, and a 3.3V high-level voltage signal is output). This can be used to connect a relay to control the switching circuit. (A small experiment where an LED lights up upon door opening will be demonstrated below.)

2.2 Key Parameters
Sensor (RP-L110):

Sensing Range: 20g~10kg
Thickness: 0.35mm, flexible structure, can fit curved surfaces
Durability: Over 1,000,000 cycles
Operating Temperature: -40℃~+85℃

Single-Channel Thin-Film Pressure Transmitter (CMCU-05/05A):

Wireless Transparent Transmission Board:

Converts data into wireless signals for remote data transmission

Main Parameters: Uses a 433M wireless RF solution, offering long transmission distance and good wall penetration. In open areas, the measured maximum distance can reach up to 500 meters. With the default antenna, the measured distance is 200 meters. Supports external suction cup antennas and RF antennas to increase the distance.

2.3 Data Collection Process

Sensor Force Applied → Signal Change
CMCU-05/05A Acquires → Converts to Pressure Value
Pressure Value Exceeds Set Threshold → Trigger Recording
Wireless Transparent Transmission → Remote Terminal Records Timestamp and Pressure Curve

III. Experimental Process
This article mainly explains the experimental process and data interpretation. For those who want to see the actual operation and the full process of the equipment in action, you can jump to the Bilibili video: https://www.bilibili.com/video/BV12ijA6AEoZ/?spm_id_from=333.337.search-card.all.click

3.1 Preparation Before the Experiment
3.1.1. Sensor Attachment: Attach the thin-film pressure sensor to the upper surface of the door handle, and use double-sided tape or adhesive tape to fix the sensor position to prevent displacement.
3.1.2. Lead Connection: Connect the sensor leads to the CMCU-05/05A acquisition board。
3.1.3. Connect the wireless transparent transmission receiver to the computer via USB.
3.1.4. Equipment Debugging: Power on and pair, confirm that wireless communication is normal.

3.2 Experimental Procedure
3.2.1.Threshold Confirmation: Perform a pressure level test on the sensor, select a threshold trigger value, and set the trigger threshold in the software.
3.2.2.Door Opening Test: There is no pressure value before gripping the door handle. Record the pressure value when touching the door handle, and the pressure value when gripping and opening the door handle. Repeat the operation more than 10 times and observe whether the threshold signal is successfully triggered each time.
3.2.3.Data Recording: Each door opening operation automatically records the timestamp, forming a door opening event log, and confirming that each door opening record is correctly uploaded.

The following data were obtained from actual door handle gripping tests (sensor attached to the upper edge):

Different handle materials, installation angles, sensor sizes, and other factors will affect the data results.

Ⅳ. Application Scenarios
4.1 Home Security and Daily Monitoring

Front Door Opening Records: Real-time recording of family members' entry and exit times, can be linked with an APP to push door opening alerts.
Refrigerator/Cabinet Monitoring: Attach to the compression surface where the refrigerator door frame contacts the cabinet body. Use the compression pressure when the door is closed as the "door closed" signal; if the door remains closed beyond a set time (e.g., 5 minutes), a mobile phone alarm is triggered to prevent cold air leakage and food spoilage.
Child/Pet Behavior Tracking: Monitor door handles of snack cabinets, study rooms, etc., allowing parents to know if a child has opened a cabinet door during a specific time period.

4.2 Health Care and Elderly Care

Activity Monitoring for the Elderly Living Alone: Record the frequency and time periods of bedroom and bathroom door openings. If no door opening action is detected for 8 or 12 consecutive hours, automatically send an alert to children or the community. Compared to wearable devices, this "unobtrusive monitoring" method is more easily accepted by the elderly and will not fail due to forgetting to wear the device.
Medication Adherence Tracking: Attach to medicine cabinet locks or bottle caps, record the daily time of opening the cabinet to take medication, assisting in determining whether the elderly person is taking medication on time.

4.3 Commercial and Public Spaces

Player Behavior Statistics (e.g., Escape Rooms): Attach to game-specific items, door handles, etc., to sense player progression and item usage in real-time, count the number of uses, and assist in analyzing game completion paths and operating habits.
Office Space Management: Monitor the usage frequency of meeting room doors and pantry doors, providing data support for space utilization analysis

4.4 Education, Research, and DIY

University electronic design teaching: as a typical teaching case for flexible sensing and embedded development, helping students understand the sensor signal chain
Maker project basic module: can be expanded to connect to platforms such as Raspberry Pi and Arduino for developing various interactive devices

V. Application Areas

VI. Application Prospects
6.1 Market Positioning: Differentiated Supplement
The current smart lock market has become mature, but it mainly covers the "lock control" level - achieving advanced functions such as remote unlocking and fingerprint recognition. This solution is not only used for induction monitoring but also for behavior analysis.

No need to replace the door lock, stick and use immediately
Controllable cost (total cost of sensor + collector + transparent transmission board is about a few hundred yuan, far lower than that of smart locks)
Applicable to all doors with handles, not limited to main entrance doors

6.2 Expansion Directions
Multi-node networking: A single host can connect to multiple collection points (main door, refrigerator, medicine cabinet) to build an overall household behavior log;

Pressure curve analysis: The grip force curves of different users vary. Combined with simple clustering algorithms, it can assist in identifying the operator's identity;

Cloud platform integration: Push data to open-source platforms such as Home Assistant and Node-RED via serial port or wireless gateway to achieve linkage with other smart devices.

6.3 Commercial Potential
It has clear commercial value in the elderly care monitoring niche market. Against the backdrop of China's accelerating aging population, the demand for low-cost, unobtrusive home-based elderly care monitoring devices continues to grow. This solution achieves 24-hour uninterrupted door activity monitoring with hardware costs under one thousand yuan, offering a significant cost-effectiveness advantage compared to smart security kits that often cost thousands of yuan.

VII. Summary
This solution takes the RP-L110 flexible film pressure sensor + CMCU-05/05A single-channel pressure collector + wireless transparent transmission board as the core, integrating pressure sensing, threshold judgment, signal output, and wireless return into a concise technical path. Following the operating steps and measured reference data provided in this document, debugging personnel can complete single-point deployment and put it into practical use within 30 minutes.

Core value: Use inconspicuous sensors to address everyday aspects - making every "door opening" meaningful.

🌿🌿🌿 Check our website : www.runeskee.com

Thin-film pressure sensor-based intelligent seat pressure sensing system: sitting posture pressure distribution

RUNESKEE — Mon, 17 Aug 2026 09:27:47 +0000

1. Measurement Plan
1.1 Experimental Equipment and Materials

1.2 Sensor Selection
Sensor Specifications

The RP-C30-ST thin-film pressure sensor is a resistive pressure sensor with a range of 20g ~ 20Kg. Its core features include:
• Response time: <1ms, fast response
• Operating temperature: -40°C ~ +85°C
• Thickness: 0.45mm, flexible, conforms to curved surfaces
• Durability: Over 1 million cycles (1Kg force flexible pressing)
Application Characteristics Analysis
• Adult body weight typically ranges from 50~100kg. In a seated posture, approximately 75% of the weight is transferred to the seat cushion (with the remainder borne by the thighs and back). This experiment uses a 9-sensor array to distribute the load, with a theoretical average force per sensor of ~75kg × 75% ÷ 9 = 6.25kg. However, actual sitting pressure is non-uniform, with the ischial tuberosity region as the core pressure zone, where peak pressure can reach 30%~40% of body weight.
• This experiment directly collects AD values from 9 channels via CMCU-05B to obtain seat cushion surface pressure distribution characteristics for subsequent posture recognition analysis.
• Scalability: For higher-weight testing scenarios, sensors with larger ranges or higher-density arrays can be selected.

1.3 Sensor Layout Design
Combined with human sitting pressure distribution characteristics, sensor positions are arranged according to target measurement areas. This experiment adopts two layout schemes, with emphasis below on Scheme 1: a 3×3 array (9 sensors) on the seat cushion plus 1 additional sensor on the backrest.

The seat cushion area uses 9 RP-C30-ST sensors arranged uniformly in a 3×3 grid, focusing on covering bilateral ischial tuberosities and surrounding core pressure-bearing soft tissue regions. This layout ensures precise core pressure data collection while optimizing sensor count for cost efficiency. If budget permits, higher-density arrays (composed of multiple single-point sensors) can be deployed.

One pressure sensor is installed on the seat backrest for pressure acquisition, paired with a single-channel acquisition board for independent backrest pressure data collection, enabling synchronized analysis of seat cushion and backrest pressures.

1.4 Acquisition System (CMCU-05B Collector + Wireless Transparent Transmission Module)

This experiment employs the CMCU-05B multi-channel thin-film pressure display with a wireless transmission module to relay data to a PC wirelessly.

The CMCU-05B is a 9-channel thin-film pressure sensor detector with a built-in screen and battery. It can display real-time pressure data and distribution curves for all 9 channels and can also connect to a computer for simultaneous data recording and storage.

Given the large number of sensors and complex wiring in seat testing, this solution includes an RS485 wireless transmission module for wireless data transfer between the collector and the host computer, while avoiding cable restrictions on the tester's movements. This module supports one-to-many wireless networking, making it highly practical for multi-test-point or multi-test-group scenarios.

1.5 Data Collection and Processing
Collection Process:
9 RP-C30-ST sensors (3×3 array)
↓
CMCU-05B multi-channel thin-film pressure collector (synchronous acquisition)
↓
Wireless transmission board (serial port → wireless transmission)
↓
Host computer software (real-time pressure cloud map + pressure curve display)

2. Experimental Procedure
This article focuses on the experimental process and data analysis of Solution 1. For a live demonstration of both solutions, you can jump to the Bilibili video:
https://www.bilibili.com/video/BV1mPJN6yEcP/?spm_id_from=333.1387.homepage.videocard.click

2.1 Pre-Experiment Preparation

Sensor Attachment: Fix the thin-film pressure sensors onto the seat cushion surface using double-sided tape or adhesive to ensure alignment with the target body parts during sitting and prevent displacement.
Wiring Connection: Connect the leads of the 9 sensors to the CH1–CH9 terminals of the CMCU-05B collector board (sensor pins are non-polarized).
Connect the wireless transmission receiver board to the computer via USB;
Device Setup: Power on and pair the devices to confirm normal wireless communication.

2.2 Experimental Procedure
Experiment 1: Empty seat state. Record data from all 9 channels; no valid pressure signals should be detected from any sensor.

Experiment 2: Upright sitting posture. Sit in a standard upright position (back straight, legs naturally shoulder-width apart) and record 9-channel data.

Data Analysis:
• Key Features:

Highest pressure values in the left and right ischial regions, with near symmetry
Pressure at the front edge of the cushion is significantly lower than in the ischial regions (difference >50%)
No backrest pressure • Conclusion: In a normal sitting posture, pressure is primarily concentrated in the ischial regions, with auxiliary support from the thighs. Pressure on the front thighs and cushion edge is minimal.

Experiment 3: Forward-leaning posture, lean the body forward (simulating desk work) and record 9-channel data.

Data Analysis:
• Key Features:

Reduced pressure in the ischial regions (due to forward weight shift)
Increased pressure in the thigh regions
Significant rise in pressure at the front edge of the cushion
No backrest pressure • Health Tip: Prolonged forward-leaning posture increases pressure on the front of the thighs and the popliteal fossa, affecting blood circulation in the lower limbs. • Conclusion: The forward-leaning posture changes the pressure distribution, and increased pressure on the front edge of the cushion is the main cause of leg discomfort.

Experiment 4: Leaning-back posture, leaning backwards (supported by the backrest, simulating a resting state), recording 9-channel data.

Data Analysis:
• Key Features:

Peak pressure in the ischial area decreases (weight is distributed to the thighs and backrest)
Pressure on the front edge of the cushion is close to zero
Backrest pressure is present • Conclusion: Leaning-back posture reduces cushion pressure, with the backrest bearing part of the load, typically resulting in greater hip comfort.

3. Application Scenarios
3.1 Office/Automotive Driving Seat Health Monitoring
Lumbar spine problems and pressure ulcer risks caused by prolonged sitting are common health concerns.

Innovation Point: Multiple studies have shown that using pressure distribution sensing combined with active pressure redistribution can effectively reduce the risk of pressure ulcers.

3.2 Seat Product R&D and Testing

Professional pressure distribution testing systems have been widely used in the field of seat R&D. This solution achieves similar functionality at an extremely low cost.

4. Application Fields

5. Application Prospects
5.1 Technology Trends

Integration of Healthcare • Smart Pressure Ulcer Prevention Cushion: Research indicates that modular pressure redistribution systems can effectively prevent pressure ulcers • Remote Rehabilitation Monitoring: Sitting posture data is uploaded to the cloud for remote assessment by therapists • Elderly Care: Automatic alerts for prolonged sitting / abnormal postures
Data-Driven Product Iteration Seat manufacturers can optimize seat design parameters by collecting massive amounts of sitting posture pressure data, enabling data-driven product iteration.

5.2 Expansion Directions

5.3 Comparison with Professional Systems

Market Positioning: This solution does not seek direct competition with professional systems but instead provides an embedded sitting posture sensing solution that can be deployed at scale, filling the gap in the low-cost smart seat market.

6. Summary
This system uses nine RP-C30-ST thin-film pressure sensors (20kg range), arranged in a 3×3 array on the seat cushion. Real-time data acquisition and transmission are achieved via the CMCU-05B multi-channel thin-film pressure display and the RS485 wireless transparent transmission module.

Core Applications:
• Sitting posture monitoring and health reminders for office/driving seats
• Pressure ulcer prevention and posture monitoring in medical rehabilitation
• Comfort quantification testing in seat product development

In the context of the growing trend of smart seating, this solution provides a feasible technical path for deploying sitting posture sensing capabilities at scale, characterized by extremely low cost, low power consumption, and ease of integration, offering clear commercial value and social significance.

🌿🌿🌿 Check our website : www.runeskee.com

Bolt Torque Measurement Solution Based on CMCU-09A Wireless Strain Acquisition

RUNESKEE — Mon, 17 Aug 2026 09:01:52 +0000

1. Solution Overview
This solution employs the RunesKee wireless strain acquisition transmitter CMCU-09A in conjunction with 350–2HA half-bridge torque strain gauges to conduct torsional testing on M10 partially threaded bolts. The strain gauges collect micro-strain signals from the bolts under torsional loads in real-time, transmitting the data wirelessly to an upper computer for analysis and processing, ultimately achieving precise measurement of internal bolt torque.

The core value of this solution lies in directly measuring the internal torque actually borne by the bolt shank, as opposed to traditional torque wrench readings (which include frictional losses at the contact surfaces). By comparing the total torque applied by the torque wrench with the internal torque measured by the strain gauges, quantitative evaluation of frictional losses in bolted connections can be achieved, providing data support for tightening process optimization.

2. Measurement System Components
2.1 Measurement Equipment and Materials

2.2 Acquisition Device: RunesKee Wireless Strain Acquisition Transmitter CMCU-09A

The CMCU-09A is an industrial-grade device dedicated to strain signal acquisition and wireless transmission. Its key features include:
• Wireless Transmission: Comprising a wireless acquisition board (transmitter) and a wireless passthrough board (receiver), it supports automatic pairing upon power-up and enables one-to-one or one-to-many networking.
• Supports three strain gauge connection methods: 1/4 bridge, half-bridge, and full-bridge
• Communication Interface: Uses RS485 protocol for direct data reading via computer connection
• Application Scenarios: Suitable for sensor manufacturing, automotive industry, aerospace, rail transportation, biomedical engineering, civil engineering, and bridge construction, among others

2.3 Strain Gauge: 350–2HA Half-Bridge Torque Gauge

The 350–2HA is a half-bridge strain gauge specifically designed for torque measurement, with the following technical characteristics:
• Nominal Resistance: 350Ω
• Configuration: Half-bridge setup with two integrated sensing grids arranged at a 90° angle
• Mounting Orientation: Must be affixed at ±45° relative to the bolt axis
• Measurement Principle: Under pure torsion, the principal stress and strain on the bolt surface at 45° satisfy material mechanics relationships, and the strain gauge directly measures linear strain in this direction

2.4 Test Object: M10 Partially Threaded Bolt

The nominal diameter of the M10 bolt is 10mm. The shank portion (non-threaded area) of the partially threaded bolt is an ideal location for strain gauge mounting, as the stress distribution here is uniform, yielding more representative measurement results.

3. Strain Gauge Selection Guidelines
3.1 Choosing Between Half-Bridge and Full-Bridge Gauges
In torque measurement, both 2HA half-bridge gauges and full-bridge torque gauges can be used. While their measurement principles and conversion formulas are identical, their applicable scenarios differ:

Notes on measurement results: Under ideal conditions (constant temperature, proper bonding technique, and correct strain gauge setup), the measurement results of half-bridge and full-bridge strain gauges are theoretically consistent. Both reflect the linear strain in the 45° direction, and the conversion formulas are identical.

However, the following differences should be noted:

Temperature effect: Half-bridge gauges require additional temperature compensation measures; otherwise, ambient temperature changes may cause zero drift. Full-bridge gauges, with their four symmetrically arranged sensing grids, have self-compensating capability.
Lead wire resistance effect: Full-bridge gauges are less sensitive to changes in lead wire resistance, making them suitable for long-distance measurements. Selection recommendations: • For this short-term, destructive test, the 2HA half-bridge gauge fully meets the requirements. • If long-term monitoring of bolt torque is needed while equipment is in operation, it is recommended to use full-bridge gauges.

3.2 Selection of number of gauges to be applied
Either 1 or 2 2HA strain gauges can be used:
• 1-gauge solution: Apply one 2HA gauge on the smooth surface of the bolt shank to measure the shear strain at a single location, which is sufficient to obtain the torque value.
• 2-gauge solution: Apply two 2HA gauges at symmetrical positions (mirrored 180°) on the bolt, and take the average to cancel the effect of bending stress, resulting in more reliable data.

4. Experimental Study
4.1 Pre-experiment Preparation

Strain gauge application: Clean and mark the smooth surface of the M10 bolt shank, and apply 350–2HA strain gauges at ±45° directions;
Lead wire connection: Connect the strain gauge lead wires to the sensor terminals of the CMCU-09A acquisition board;
Connect the wireless transmission receiver board to the computer via USB;
Equipment debugging: Power on and pair the devices, confirm normal wireless communication. 4.2 Experimental Procedure

Step 1: No-load condition
• Fix the bolt on the screw torque-to-fracture testing machine, ensuring the screw is not subjected to any load; zero calibrate and record a stable baseline as the reference value for subsequent strain calculations.

Step 2: Torsional loading (tightening torque)
• Steps: Use a torque wrench to apply pure tightening torque to the screw (avoid generating lateral forces), and record the micro-strain data;
• Data analysis: Calculate the internal torque of the bolt at each time point using the conversion formula.

5. Experimental Data Analysis
First set of data:

Third set of data:

5.1 Test Result Data

5.2 Method for Converting Micro-strain to Torque
According to the principles of material mechanics, under pure torsional loading of the bolt, the relationship between the maximum shear strain on the surface and the torque is:

Where:

5.3 Simplified Calculation
Substituting typical parameters of M10 bolts and steel, the simplified formula is obtained:

That is: every 1000με ≈ 27.5 N·m

Example: If the strain gauge reading is 500με, then the internal torque of the bolt ≈ 500 × 0.0275 = 13.75 N·m

What is the actual internal torque corresponding to the "wrench torque" and "microstrain"? We can back-calculate using the measured strain-torque ratio (approximately 0.031 N·m/με).

Taking the maximum load as an example:

Wrench reading 35 N·m
Microstrain 1183 με
According to the simplified formula M internal = 1183 × 0.0275 ≈ 32.5 N ⋅ m

Note: This 32.5 N·m is the internal torque of the bolt calculated from the strain. The wrench reading is 35 N·m, and the two are very close! This indicates that under this experimental condition, the end face friction and thread friction are very small.

Under this experimental condition (pure torsion, no axial force), the wrench torque is almost entirely converted into the internal torque of the bolt, with extremely low friction loss. The data conforms to the theoretical formula.

5.4 Physical Significance of the Two

5.5 Why Are the Two Not Equal?
When tightening a bolt with a torque wrench, the total input torque is consumed in three aspects:
• Thread friction (approximately 40–50%): Converted into torsional deformation of the bolt (the measurement object of this experiment)
• Bearing surface friction (approximately 40–50%): Friction between the bolt head/nut and the connected parts, not transmitted to the bolt shank
• Effective preload (remaining portion): Converted into axial tensile force
Therefore, the torque wrench reading ≠ the internal torque of the bolt.

5.6 Advantages of This Solution
The traditional torque method cannot determine the actual torque borne inside the bolt, whereas this solution directly measures it through strain gauges, offering the following advantages:

Precisely obtain internal torque: Can quantitatively calculate the shear stress at the critical section of the bolt
Evaluate friction loss: By comparing the wrench reading with the internal torque, the friction coefficient can be calculated
Failure warning: Real-time monitoring of strain values, providing early warning when approaching the material's yield limit
Process recording: Wireless acquisition can fully record data throughout the entire process from loading to fracture

6. Application Scenarios
This measurement solution has significant application value in the following industrial scenarios:

6.1 Optimization of Tightening Process Parameters
During machine production and processing, this solution can be used to precisely determine the appropriate installation force. By establishing a relationship curve of "applied torque - internal torque - preload force," the optimal tightening parameters can be determined, avoiding loosening due to insufficient torque or bolt fracture due to excessive torque.

6.2 Bolt Material Quality Verification
For high-strength and high-safety scenarios (such as automotive chassis, wind turbine towers, and rail transit), it is essential to ensure that bolt materials meet design requirements. This solution enables direct measurement of the mechanical response of bolts under torsional loads, verifying whether the actual material performance meets standards.

6.3 Finite Element Analysis (FEA) Verification
After establishing a finite element model of the bolted connection, experimental data is required to validate the model's accuracy. The microstrain-internal torque measurement data provided by this solution serves as a benchmark for FEA model calibration and verification.

6.4 Bolt Fracture Failure Analysis
When bolts fracture during use, it is necessary to determine the failure mode (overload fracture, fatigue fracture, hydrogen embrittlement, etc.). This solution helps establish the mapping relationship between torque and stress, providing data support for failure analysis.

6.5 Intelligent Tightening Quality Monitoring
By combining torque-angle curves and strain data, an intelligent recognition model for tightening quality can be established to identify abnormal states such as normal tightening, floating locks, and tilting, enabling real-time warnings during the tightening process.

6.6 Full Lifecycle Torque Management
In applications requiring long-term monitoring, such as wind power and high-speed rail, a "digital twin assembly" system can be established using wireless strain acquisition technology, enabling torque data traceability and full lifecycle management for each bolt.

7. Experimental Precautions

Strain gauge bonding process: The surface of the elastic element must be cleaned and polished, and specialized adhesive should be used to ensure firm bonding and accurate alignment.
Zero-point calibration: Record initial values under no load to perform zero-point correction.
Wireless interference: Avoid use in environments with strong electromagnetic interference and ensure no metal obstructions between the transmitter and receiver.
Loading speed: Gradual step-by-step loading is recommended to record a complete torque-strain curve.
Safety precautions: For bolt torsion fracture experiments, be aware of potential splintering upon fracture and install protective covers.
Summary
This solution, based on the RunesKee wireless strain acquisition transmitter CMCU-09A and the 350–2HA half-bridge torque strain gauge, achieves precise measurement of internal torque under torsional loads for M10 bolts. By distinguishing torque wrench readings (total torque) from strain gauge measurements (internal torque), it quantitatively evaluates frictional losses in bolted connections, providing a scientific basis for tightening process optimization, quality control, and failure analysis.

The solution is applicable to fields such as automotive manufacturing, rail transit, and wind power equipment, offering advantages like high measurement accuracy, data traceability, and convenient wireless transmission, making it an effective tool for bolt connection quality assurance.

🌿🌿🌿 Check our website : www.runeskee.com

Where is your hand weak? One grip tells all - Measure hand force with CMCU-05B

RUNESKEE — Mon, 17 Aug 2026 08:22:33 +0000

1. What is the CMCU-05B for?
The CMCU-05B is a multi-channel thin-film pressure sensor detector that can connect up to 9 thin-film pressure sensors. After attaching the sensors to the measurement points and connecting them to the display, pressure values can be directly shown (supports units: g/kg/N).

Its core function: simultaneously monitoring pressure distribution across 9 points. For example, when multiple sensors are attached to different positions on a grip ball (such as the thenar eminence, thumb, index finger, middle finger, ring finger, and little finger), gripping the ball will display the values of each channel on the screen in real time - the higher the value, the greater the force exerted at that position.

Practical applications: Rehabilitation therapists or family members can observe which parts of the hand exert more or less force when gripping the ball, and compare force changes across different grip postures or before/after rehabilitation training.

2. What do you need to prepare?

3. Where to attach the sensors?
Important note:
The sensor is a flexible film - it measures pressure wherever it's attached. Want to measure a specific spot? Just attach it there.

Application: Simultaneously measuring force at 6 key hand positions

If you want to check whether each finger's strength is normal or if the palm is compensating - for example, after stroke rehabilitation, to assess which fingers haven't fully recovered or if the palm is overcompensating - the CMCU-05B (with 9 channels, only 6 needed here) is very convenient.

Attach to 6 key positions (5 finger pads + the thenar eminence's corresponding ball position):

How to attach?
• Use double-sided tape to stick the sensors to the pads of the 5 fingers and the ball position corresponding to the thenar eminence.
• Secure the sensors with medical tape to prevent movement during gripping.

4. How to wire it?
Using the CMCU-05B (9-channel, with display)

Connect the two thin wires of each of the 6 sensors to the CH1 ~ CH6 terminals of the CMCU-05B (polarity doesn't matter; any 6 of the 9 channels can be used).
The CMCU-05B module has a built-in 450mAh battery and can be used directly (no computer needed), though it also supports computer connection.

5. How to view the data?
Method 1: Directly check the screen
The 2.0-inch color display shows values for all 9 channels. The connected sensors display real-time pressure values, while unused channels show 0. The higher the force at a hand position, the larger the corresponding channel number. Supports switching between g/kg/N units.

Method 2: Connect to a computer

Open the manufacturer's data acquisition software on the computer.
Select the corresponding COM port and click "Connect."
The software displays real-time pressure values and can also show a graph.
The software includes a "Save" function to store collected data as files for later analysis and processing.

6. What exactly is measured?
For the experiments below, you can choose one to try:

Experiment 1: Hand force distribution test (measure 6 positions simultaneously)

Attach 6 sensors to the grip ball and connect it to the 05B.
Hold the grip ball with your hand corresponding to the thin-film pressure sensor positions (simulating a grasping motion).
Observe the values of the 6 channels on the screen:
For a normal person, the index and middle fingers exert the most force, while the little finger exerts the least.
If the value for a certain finger is significantly low (e.g., close to 0), it indicates that this finger may not be able to exert force.
If the thenar eminence value is very high, but all finger values are very low, it suggests the palm is "compensating" - a common adverse pattern in stroke rehabilitation.
You can test the left and right hands separately and compare the differences between corresponding fingers. Experiment 2: Pre- and post-rehabilitation comparison
Pre-rehabilitation test: Use the 05B to measure the force output at 6 positions on the hand once and save the data.
Conduct a period of rehabilitation training (e.g., squeezing a stress ball, finger opening and closing exercises).
Post-rehabilitation test: Measure again under exactly the same conditions (same grip, same posture).
Compare the two sets of data:
Has the finger with the previously low value increased? → Indicates finger strength has recovered.
Has the previously high thenar eminence value decreased, while finger values increased? → Indicates the force pattern has shifted from "palm compensation" to "active finger force application," a sign of good rehabilitation progress.
No change or worsening → Indicates the rehabilitation plan needs adjustment.

7. Summary
If you want to know how much force each of the five fingers exerts simultaneously: use the CMCU-05B with 6 sensors, attach them to 6 positions (5 fingers + the thenar eminence corresponding position on the ball), and read the pressure changes directly. The finger whose corresponding channel value is small is the one lacking strength. If the thenar eminence value is very high but all five finger values are very low, it indicates the palm is compensating. It's that simple.

🌿🌿🌿 Check our website : www.runeskee.com

Want to know how strong your grip is? Squeeze it and find out - count your grip cycles with the CMCU-05/05A

RUNESKEE — Mon, 17 Aug 2026 07:58:39 +0000

1. What is the CMCU-05/05A?
The CMCU-05/05A is a single-channel thin-film pressure sensor tester that can connect to one thin-film pressure sensor. After attaching the sensor to the target position and connecting it to the module, it converts pressure signals into numerical values. The version with a screen (05A) can display directly, while the version without a screen (05) needs to be connected to a computer for viewing.
Its core function: real-time monitoring of pressure changes, outputting continuous numerical values. For example, attach the sensor between the two handles of a grip strengthener. Each time you squeeze to the bottom, the pressure value increases significantly, and it drops when you release your hand. By recording the pressure curve with computer software, you can see the waveform corresponding to each grip action.
Practical application scenarios: Rehabilitation therapists or family members can use the pressure waveform to count how many grip training sessions a person has done in a day, or compare the number of continuous grip cycles before and after rehabilitation. Simply put, to record the number of grip cycles, you can use the single-channel CMCU-05/05A together with computer software for analysis.

2. What do you need to prepare?

3. Where do you attach the sensor?
Important tips:
The sensor is a flexible thin film. Attach it where you want to measure pressure. If you want to measure a certain spot, just attach it there.
Taking a grip strengthener as an example: Attach the sensor to the inner side of both handles of the grip strengthener, at the position where they make contact when squeezed to the bottom.
How to attach it?
• Use double-sided tape to stick the sensor to the inner side of one handle, at the spot that gets pressed when the other handle is squeezed to the bottom.
• Then wrap the edges of the sensor with medical tape to prevent it from shifting during gripping.

4. How to connect the wiring?
Scenario A: Using the CMCU-05A (with screen)
Plug the sensor cable into the sensor interface, and you can see the value changes in real time on the screen.

Scenario B: Using the CMCU-05 (without screen)

Connect the sensor cable to IN+ / IN- (no polarity, connect either way)
Power supply: Connect the red wire of the power cable to V+, and the black wire to V- (DC 5~24V; a regular 5V phone charger works too)
Communication: Connect the A cable of the RS485 line to A+, and the B cable to B-. Connect the other end to a computer or microcontroller device via a USB-to-485 module.

5. How to view the data?
Method 1: View directly on the screen (05A only)
The screen displays the pressure value in real time. Double-click the function button to switch units (g/kg/N). The value increases when you squeeze to the bottom and decreases when you release your hand.
The screen only shows real-time values; it does not automatically count cycles. To count the number of squeezes, secondary development (connecting to a microcontroller for processing) is required.
Method 2: Connect to a computer (works with both 05 and 05A)

Open the data acquisition software provided by the manufacturer.
Select the corresponding COM port and click 'Connect'.
The software will display a real-time pressure curve. Each waveform that goes "from low to high, then back to low" corresponds to one complete grip action.
The computer software can save the collected data. During training, enable the save function to record the training process as a file for analysis and processing.

6. What exactly is measured?
You can choose one of the following experiments to try:
Experiment 1: Measure how many times you can squeeze in 1 minute (basic endurance test)

Connect to the computer and open the acquisition software to prepare for recording the waveform.
Start the timer and continuously squeeze the hand dynamometer as fast as you can for 1 minute (each squeeze must be fully depressed and then completely released).
Stop when the 1 minute is up.
Count the number of waveforms; this is the number of grips within 1 minute. The higher the count, the better the endurance. Experiment 2: Compare left and right hand endurance
Left hand test: Continuously squeeze the hand dynamometer as fast as you can for 1 minute (each squeeze must be fully depressed and then completely released). Connect to the computer to record the waveform, and count the number of waveforms after finishing.
Right hand test: Repeat the test using the same 1 minute duration and your fastest speed.
Compare the counts of the left and right hands: The hand with more squeezes has better endurance, while the hand with fewer squeezes needs more training. Experiment 3: Before and after rehabilitation comparison
Pre-rehabilitation test: Measure the number of grips in 1 minute and record the waveform count.
Undergo a period of rehabilitation training.
Post-rehabilitation test: Use identical conditions (same 1 minute duration and your fastest speed) to measure the grip count again.
Comparison: If the count has increased, endurance has improved; if it has stayed the same or decreased, the rehabilitation plan needs adjustment.

7. One-sentence summary
Attach the sensor between the two handles of the hand dynamometer, connect it to the CMCU-05/05A, and connect to the computer to view the waveform. Each waveform that goes "from low to high and back to low" represents one grip action. Count the number of waveforms to know how many squeezes were made. It's that simple.
🌿🌿🌿 Check our website : www.runeskee.com

Standing · Walking · Running · Jumping: How Does Plantar Pressure Distribution Change? Measure It with CMCU-05B

RUNESKEE — Mon, 17 Aug 2026 07:37:06 +0000

I. What Is CMCU-05B?
The CMCU-05B is a multi-channel thin-film pressure sensor detector equipped with a display screen, capable of connecting up to 9 thin-film pressure sensors. Once the sensors are attached to the target measurement sites and connected to the detector, pressure values can be directly acquired.

II. What Do You Need?

III. Where to Place the Sensors?
Important Note:
The sensor is a flexible, soft film that can be applied to various flexible-surface scenarios - attach it wherever you need to measure pressure.
Application scenario: Simultaneous measurement of pressure at multiple key plantar locations.
To analyze the forces exerted by the heel, forefoot, and toes during walking, multiple sensors can be arranged on the insole and connected to the CMCU-05B multi-channel thin-film pressure detector.
The following is a 5-point placement scheme compiled from publicly available research, provided for reference only. You may adjust flexibly according to your specific testing requirements.
Place 5 sensors at 5 key locations on the insole:

How to Attach:
• Use medical tape to adhere the 5 sensors to their corresponding positions on the insole.
• If the selected sensors lack adhesive backing, wrap medical tape around the edges of each sensor to prevent displacement during walking.

IV. How to Connect the Wiring?
Connect the two leads of each of the 5 sensors to the CH1 ~ CH5 terminals of the CMCU-05B (sensor polarity is not orientation-sensitive).
This thin-film pressure detector features a built-in 450 mAh battery, enabling standalone use. It also supports simultaneous data acquisition and storage when connected to a computer.
Long-press the power button to turn on the device. From the main menu, access either the numerical display interface or the curve graph interface for real-time pressure monitoring.

V. How to Read the Data?
Method 1: Directly on the CMCU-05B (9-Channel) Screen
From the main display menu, enter the data view to see real-time pressure values for all 9 channels. The unit can be switched among g, kg, and N.
Method 2: Computer Software
Open the acquisition software provided by the manufacturer on your computer.
Select the corresponding COM port and click "Connect."
The main interface displays pressure acquisition; the curve graph can be [i]opened from the upper-left corner.
The software includes a "Data Save" function, allowing you to store acquired data as spreadsheet files for subsequent analysis and processing.
The software also supports modifying configuration parameters, pressure thresholds, baud rate, sampling frequency, and enabling/disabling specific channels.

VI. Experimental Testing
Given the large number of sensors, extensive wiring, and dynamic activities involved in this plantar experiment - all requiring high flexibility - we paired the setup with an RS485 wireless transparent transmission board. This enables wireless data transmission to computers and other devices, eliminating restrictions on the subject's movement space due to cable length. This method supports both one-to-one and one-to-many wireless acquisition, making it highly practical for scenarios involving numerous measurement points or multiple test groups.

Experiment 1: Static Standing - Observing Pressure Distribution
Place the insole with 5 attached sensors into the shoe and wear it.
Stand upright and hold still for 5 seconds, with both feet bearing weight naturally.
Observe the 5-channel values on the screen:

The heel shows the highest value → the heel bears the greatest force (normal).
The forefoot and lateral heel show similar values.

Conclusion: The subject's standing posture primarily relies on the heel for body support.
Experiment 2: Gait Analysis - Dynamic Walking
Building on the static test, observe pressure changes during walking.
Place the insole with sensors into the shoe and wear it.
Power on the device and connect to the computer to begin recording.
Walk normally for several steps, acquiring values or opening the curve graph to capture pressure variations.
Analyze the subject's gait data:

The initial portion of the curve represents static standing: the heel (yellow line) shows the highest force. During walking initiation: the peak force shifts from the heel (yellow line) to the anterior forefoot (black line) and the base of the great toe (red line).
During continuous walking, regular waveforms are observed. The force application pattern remains consistent with each step, indicating valid data acquisition without sensor displacement. The subject's walking pattern tends to rely on the anterior forefoot for propulsion.

Experiment 3: Gait Analysis - Dynamic Jogging in Place
Building on the walking test, observe plantar pressure distribution changes during jogging.
Curve graph data analysis: - The initial portion shows the pre-start posture: one foot is relaxed in preparation, with relatively even pressure distribution across all plantar regions. - Entering jogging phase: one foot is relaxed (even values across all regions), then lifts off (all values drop to 0), followed by heel strike (yellow line), then forefoot engagement (red and black lines) for forward propulsion. The data shows that during continuous jogging, the subject barely uses the heel, instead frequently applying force through the forefoot. Only after jogging completion does the heel (yellow line) resume standing support. - Regular waveforms are observed throughout jogging, with consistent force patterns for each step, confirming valid data and no sensor displacement. The subject's jogging pattern tends toward forefoot-driven propulsion.

Experiment 4: Jumping Posture Analysis
Monitor which plantar regions participate in force application during jumping and the distribution of force magnitude.
Curve graph data analysis: - The initial portion shows the pre-jump standing posture: the heel (yellow line) supports the body. - During the knee-bend preparatory phase, the "loading" force on the plantar surface remains approximately equal to the subject's body weight. At take-off, the impact force on the base of the great toe (red line) and the anterior forefoot (black line) can reach 2 to 4 times the body weight. - Variations in take-off posture for each jump can be identified through pressure changes at specific sensing points, revealing the degree of force contribution from each region.

VII. Summary
By deploying thin-film pressure sensors at 5 key plantar locations and synchronously acquiring data via the CMCU-05B multi-channel detector, real-time plantar pressure distribution can be obtained for four conditions: standing, walking, jogging, and jumping. The results for this subject are as follows: during static standing, the heel bears the primary load; during walking, the center of pressure shifts anteriorly, with the forefoot and base of the great toe becoming the primary force application points during the push-off phase; during jogging, the heel is almost unloaded, with the gait transitioning to forefoot-driven propulsion; during jumping take-off, the peak pressure at the forefoot and base of the great toe can reach 2–4 times the static body weight.

Curious about your own plantar pressure distribution? Try this experiment yourself.
🌿🌿🌿 Check our website : www.runeskee.com

CMCU-09 Wireless Strain Acquisition Kit - Quick Start Guide

RUNESKEE — Sat, 15 Aug 2026 11:15:41 +0000

1. Strain Gauge Wiring Diagram

2. Wireless Transmission Schematic

3.Hardware Wiring

3.1 Below is the One-to-One Wireless Communication Operation Guide

I. Hardware: Required Items for Operation

Full-Bridge Strain Gauge
Wireless Acquisition Board
Wireless Receiver Board
3.7V Battery (3.7V~12V batteries or power adapters can be used)
USB Cable

II. Hardware: Wiring Schematic

Wiring Diagram/Connecting to Computer

3.2 Below is the One-to-Many Wireless Communication Operation Guide(Example: One-to-Three)

Note Before operating in one-to-many mode, refer to the one-to-one method above to individually connect each acquisition board and set the address numbers (Address 1, Address 2, Address 3, etc.) for each board

I. Hardware: Required Items for Operation

Full-Bridge Strain Gauge x3
Wireless Acquisition Board x3
Wireless Receiver Board x1
3.7V battery x3
USB data cable x1

(One-to-three) Operation Checklist

II. Hardware: Wiring Schematic

Wiring Diagram/Connecting to Computer

4. Computer side: Install USB driver
Connect the hardware wiring properly and plug it into the computer's USB port.
Then open the USB driver file included in the provided materials and double-click to install the CH340/CH341 driver.

After successful USB installation, open the computer's Device Manager to check the corresponding COM port number.

5. Computer side: Software usage

Open the software, select the port number (if the port number is not displayed in the dropdown menu, you can manually enter the corresponding port number), and connect to start formal use.

When the following image appears, it indicates a successful connection, and data read/write operations can proceed normally. If it does not appear, check whether the communication cable between the transmitter and USB is properly connected!

The software has a graph display function in the top-left corner, which can be clicked to view the pressure curve.

Multiple transmitters can be networked to display multiple pressure curves, with a maximum of 10 pressure curves displayed simultaneously.

Network interface

6. Calibration and Usage

6.1. Measuring microstrain μ ε
For microstrain measurement, simply select the bridge circuit, resistance value, and corresponding mounting method in the microstrain column, save the parameters, and then start collecting strain gauge data.

Additionally, regarding the strain gauge mounting method, the requirements are very strict. Non-professionals may produce significantly inconsistent data. In such cases, it is generally necessary to reattach the strain gauge before measurement. The data output by the transmitter is collected from the strain gauge signal terminals. If data anomalies occur, it is recommended to check the strain gauge. Furthermore, the lead length should not be too long, as the cable itself may introduce signal interference and attenuation. Gradual increases or decreases in data may be due to temperature effects, which can be ignored. When the object undergoes significant deformation, the data will change exponentially.

6.2. Measuring other deformations, strains, pressures, etc.

For measuring other deformations, strains, or pressures, data calibration is required for the actual application scenario.

Calibration method:

When a pressure sensor/strain gauge sensor is first connected to the transmitter module, it must be calibrated before normal use. Calibration mainly involves two steps: zero calibration and calibration setting.

Step 1: Disable the write protection function (if already disabled, this step can be skipped to avoid repetition).

Step 2: Zero calibration: Remove all objects from the weighing pan (tray), send the zero calibration command, and permanently save the current AD value as the zero point (initial value).

Step 3: Calibration setting: Place a standard weight on the weighing pan (the weight should not be too light, preferably more than 20% of its range), input the weight value, and send the weight calibration command. When the data returned by the module matches or is very close to the weight value, calibration is complete. If unsatisfactory, repeat the weight calibration command.

7. [Appendix: Introduction to the principles of measuring various forces with strain gauges]

A strain gauge is a sensor used to detect deformation in an object. The amount of deformation an object undergoes is extremely minute. Moreover, deformation occurs only when the object is subjected to an external force (such as gravity, pressure, tension, etc.). The greater the force applied to the object, the larger the deformation. This deformation can be measured by attaching a strain gauge to the surface of the object. The greater the deformation of the object, the stronger the signal output by the strain gauge! This principle is the basis for common electronic scales. Figure 1 below shows a 40kg-capacity load cell, where the strain gauge is horizontally attached to the beam. When force is applied, this area bends and deforms, and it is protected by a white soft coating. Thanks to this high-precision mounting process, even a force as small as 1g can be detected.

Although using strain gauges to measure object deformation involves many interference signals during the mounting process and temperature effects during experiments, strain gauges remain the best solution for detecting micro-strain!

Some may ask: 'I'm measuring stress, micro-strain, or other forces, not weight! I need micro-strain data—how do I account for deformation?' In reality, whether measuring micro-strain or force, the principle is the same, grounded in physical mechanics. When force causes deformation, the strain gauge simply converts the degree of deformation into an output signal. After connecting the strain gauge, gently tapping it will show the data changing geometrically. Alternatively, you can observe the changes using the curve charts in our debugging software. If you only need to observe the general trend of an object's deformation, simply connecting the strain gauge will suffice.

🌿🌿🌿 Check our website : http://www.runeskee.com