DEV Community: circuitrocks

An ESP32 and Eight ToF Sensors Give This Antique Lamp a Sixth Sense

circuitrocks — Wed, 22 Jul 2026 22:06:54 +0000

What if a floor lamp could feel you crossing the room and answer with light and sound?

That is the trick behind Bloom Chandelier, an interactive installation built around a brass floor lamp handed down from the maker's great-grandmother. Instead of a switch, the lamp watches the space around it. Walk closer and it glows brighter while soft tones swell up from nowhere. Step away and both the light and the sound fade back into silence, leaving a short trail behind you like a wake.

How does it know you are there?

Eight VL53L1X time-of-flight sensors ring the lamp's collar, giving it a full 360-degree view that reaches roughly four feet out. These are not motion detectors. Each one measures actual distance many times a second, so the firmware can react to how near you are rather than just whether you moved. The catch: every VL53L1X ships with the same default I2C address, so eight of them on one bus would collide instantly.

The wiring answer

An Adafruit HUZZAH32 ESP32 Feather runs the show, talking to the sensors through a PCA9548A eight-channel I2C multiplexer. The code polls each sensor one at a time in a round-robin loop, switching multiplexer channels so no two sensors ever share the bus at once. Aiming each sensor outward also keeps their infrared beams from bleeding into each other. Those distance readings drive a 59-pixel warm-white LED strip split into eight zones, one per sensor, with brightness following a squared proximity curve so the glow ramps up fast as you approach. The same numbers stream over USB serial to a Raspberry Pi 4 Model B, where a Python engine maps each sensor to one note of a two-octave C major pentatonic scale. The notes are not synth patches but recordings of fingers circling wine-glass rims, pitch-shifted in SciPy from four sampled anchors.

Try a smaller version

You do not need eight sensors to learn the core ideas here. Wire a single VL53L1X to an ESP32 over I2C, read the distance, and map it to the brightness of one LED. Once that works, add a PCA9548A and a second sensor to practice channel switching, the exact skill that lets Bloom Chandelier scale to eight. The full write-up, sensor pinouts, and build photos are on the Hackster project page.

Originally published on blog.circuit.rocks.

esp32 #esp8266 #iot #wifi #circuitrocks

This Raspberry Pi Arcade Cabinet Exists Only for Chrome's Dino Game

circuitrocks — Wed, 22 Jul 2026 09:07:36 +0000

The Wi-Fi drops, a little pixel Tyrannosaurus starts running across a blank browser tab, and you tap the spacebar to keep it hopping over cacti. That offline Chrome screen is the accident a hardware hacker named Paul turned into a full arcade cabinet, so he can play the Dinosaur Game whether or not the connection ever comes back.

What Paul actually built

Instead of cloning Atari's original Pong cabinet at full size, Paul shrank it from 600 mm down to 450 mm wide so it fits in a home office. A 19-inch 4:3 Dell LCD sits where a bulky CRT would have gone, framed with black T-molding, a coin slot, a lock, and a custom serial plate modeled on real Atari hardware. Inside, the electronics are almost comically simple: a Raspberry Pi 3 Model B, a single 24 mm arcade button, and a pair of Logitech speakers. All that empty space became hidden storage, including a compartment tucked behind the hinged coin slot.

How the software ties it together

The Pi boots straight into a fullscreen version of the game using FullPageOS, a kiosk-mode Raspberry Pi image that launches Chromium on startup. High scores are saved locally, permanent dark mode helps the page vanish into the black cabinet, and CRT-style scanlines fake the old monitor look. The 24 mm button wires to a single GPIO pin with a pull-up, so one press is the entire control scheme. Paul also fires a webhook to Home Assistant when a game ends, and after 10 seconds of no input the cabinet plays itself, copying the attract mode on classic machines.

Why it is a good first cabinet build

This is a friendly project for a school robotics club or a capstone team because the electronics stay minimal while the fabrication teaches real skills. You get GPIO input handling, Linux kiosk configuration, and a home-automation webhook, without needing to write a game engine from scratch. Paul is already planning a faster board for heavier CRT effects and motion sensing to wake the screen. A Raspberry Pi 3 and a 24 mm arcade button from circuit.rocks are enough to start your own version. Full build details are on the Hackster writeup, and the kiosk image lives at the FullPageOS repo.

Originally published on blog.circuit.rocks.

raspberrypi #rpi #singleboardcomputer #linux #circuitrocks

Arduino UNO Q Arcade Bundle Turns One Board Into a Retro Console

circuitrocks — Wed, 22 Jul 2026 04:07:19 +0000

What does it actually take to build your own arcade cabinet in an afternoon? Arduino's answer is one board and a step-by-step guide. The new UNO Q Arcade bundle packs almost everything you need to turn the UNO Q into a working retro games console, following the same DIY-kit format as the earlier UNO Q Synth bundle.

What comes in the box

The bundle is built around the 4GB RAM version of the Arduino UNO Q, plus three Modulino nodes: Buttons, Joystick, and Movement. Those Modulinos snap on over I2C using Qwiic connectors, so there is no soldering to get your controls wired up. The guide walks you through installing RetroArch, the popular emulation front-end, so a single board can stand in for a whole shelf of classic consoles, home computers, and arcade machines. Want to make games instead of just playing them? The UNO Q also runs the open-source Godot engine for native titles.

Why the UNO Q can pull this off

The UNO Q is a real break from the rest of the UNO family. Alongside an STMicroelectronics STM32U585 microcontroller, it carries a Qualcomm Dragonwing QRB2210, a quad-core Arm Cortex-A53 system-on-chip. That "dual-brain" layout means the board boots straight into a Linux OS and behaves like a full single-board computer. The Arcade bundle leans entirely on the Linux side: the Dragonwing chip does the emulation heavy lifting while the STM32 microcontroller stays free for real-time input. Watch two things on cost. The kit lists at $113.64 (dropping to $90.90 with the 20% launch discount), and it does not include the Arduino USB-C Hub you need for HDMI output, which is a separate $16.34.

Try it yourself

The one part the bundle skips is the housing. Arduino ships the design files, but you print the handheld shell yourself, so budget a few hours at the printer. For a school robotics club or an ECE elective, this is a tidy intro to Linux on embedded hardware, I2C peripherals, and emulator configuration all in one build. Read the full bundle breakdown on Hackster before you order, and add the USB-C Hub to your cart, or you will end up with a console that has nowhere to show the picture.

Originally published on blog.circuit.rocks.

arduino #arduinoprojects #electronics #embedded #circuitrocks

AirMeter: Stream an AN870 Multimeter's LCD to Your Browser

circuitrocks — Tue, 21 Jul 2026 22:07:19 +0000

Want live multimeter readings on screen during a build video without fighting glare, focus hunt, and awkward camera angles? You can, and the parts list is short: an ANENG AN870 meter (any clone built on the DTM0660 chip works), an RP2040 board to sit inside it, a pair of 433 MHz HC-12 radios, an ESP32-C3 to host the page, and one small comparator board you will make yourself.

YouTuber Bits und Bolts got tired of those filming headaches and built AirMeter, an open-source mod that taps the meter's own LCD signals and redraws the display live in a web browser or as an OBS source. No proprietary app, no cloud account, no soldering to a hidden data port that may not even exist.

Reading a screen that does not want to be read

That last point is where the project gets clever. The AN870 has a hidden UART, but the manufacturer left the processor pin it needs disconnected under a blob of epoxy, so serial access was a dead end. Instead, the RP2040 samples the signals that drive the LCD directly. That display is a 4x15 multiplexed matrix: 60 individual segments controlled through only 19 physical traces. Those lines do not carry clean digital logic, they carry four-level analog waveforms, so a custom board populated with five LM339 comparators squares them into levels a microcontroller can actually read.

Once the RP2040 has clean signals, it decodes each digit, decimal point, and unit icon, then sends the reading over a low-power HC-12 link at 433 MHz to the ESP32-C3 receiver. The ESP32-C3 serves a tiny web page that faithfully rebuilds the meter's LCD in any browser on your network.

The part you would repeat for your own meter

The tedious step is mapping the matrix. Bits und Bolts probed every common (COM) and segment (SEG) line with an oscilloscope and a test jig, matching each trace to the digit or icon it lights. Do that once and the firmware knows where every reading lives. Because the same DTM0660 chip hides inside a lot of budget meters, the method ports to more than just the AN870, you just re-map the segments. Schematics, board files, and firmware are on the build page: https://www.hackster.io/news/this-modded-multimeter-streams-its-screen-straight-to-your-browser-c46d844be09b

Originally published on blog.circuit.rocks.

esp32 #esp8266 #iot #wifi #circuitrocks

ESP32 Mesh Replaces a $120k Bowling Scoring System for $1,600

circuitrocks — Tue, 21 Jul 2026 09:02:46 +0000

What do you do when the quote to fix your bowling alley's scoring comes back at $80,000?

A Hacker News poster going by section33 bought an abandoned 8-lane center and got exactly that number, with parts alone running about $4,000 per lane pair. Then he opened up the pinsetters. The 70-year-old machines are almost purely mechanical, and the expensive "advanced" controller they were paying for mostly just closed one relay to kick the pinsetter. That is a job for a $6 microcontroller, not a six-figure cabinet. His replacement, OpenLaneLink, lands somewhere around $200 to $400 per lane pair, or roughly $1,600 for the whole house.

How the wiring actually works

Each lane pair gets an ESP32 node. The node watches IR break-beam sensors to detect a ball crossing the foul line and the pins falling, reads machine state through optocouplers so the 1950s wiring never touches a 3.3V GPIO pin directly, and fires a relay to trigger the pinsetter cycle. Optocoupler isolation is the part worth copying: bowling machines run mains-adjacent voltages and back-EMF from those motor contactors will happily kill an ESP32 that is tied straight to them.

The nodes talk over ESP-NOW, Espressif's connectionless 2.4 GHz protocol that skips the whole Wi-Fi association handshake, so a pin-fall event reaches the gateway in single-digit milliseconds without a router in the loop. RS485 sits underneath as a wired fallback, which is the right call in a metal-heavy building full of motors. A gateway node connects over UART to a Raspberry Pi running Redis and a scoring state machine, and from there it is a normal web stack: middleware, React, and WebSocket pub-sub. Any front-end dev on the team can build a lane UI without touching firmware.

Try a smaller version of this

You do not need a bowling alley to practice the pattern. Wire an IR break-beam pair to two ESP32s, send the trip event over ESP-NOW, and push it to a Pi over UART at 115200 baud. That is the same sensor-to-mesh-to-server chain, minus the pinsetters. Add a PC817 optocoupler on the input side and you have handled the isolation lesson too. Watch out for one gotcha: ESP-NOW and Wi-Fi station mode must share a channel, so lock the channel explicitly if your gateway is also online.

The full architecture write-up, including planned DMX light shows and tap-to-pay kiosk bowling, is in the Hacker News thread. The author says hardware, firmware, and software will be open sourced once it stabilizes.

Originally published on blog.circuit.rocks.

esp32 #esp8266 #iot #wifi #circuitrocks

PocketBeagle 2 Security Camera: Fully Offline, No Cloud

circuitrocks — Tue, 21 Jul 2026 04:06:50 +0000

Want a home security camera that never sends a single frame to the cloud? Here is the parts pile to make it happen: a PocketBeagle 2 single-board computer, a camera module, an 18650 cell for backup power, a watertight aluminum enclosure, and a small custom PCB to tie the power and USB lines together. Clem Mayer put exactly this stack together, and the whole thing runs person detection on the board itself with zero outside servers involved.

What the build actually does

The camera watches for people and only records when someone walks into frame, then stops a few seconds after they leave. That keeps storage tiny. Every clip lands on local media and auto-deletes after 72 hours, though you can plug in extra USB storage to stretch that window. Nothing leaves the house, so a data breach at some camera company cannot expose your living room. Mayer salvaged the front glass and swivel mount from a cheap dummy camera, which is a nice reminder that not every part needs to be bought new.

The technical bits worth copying

Detection runs on OpenCV plus a lightweight deep neural network, both executing directly on the PocketBeagle 2. Since the board has limited native interfaces, a Microchip USB2514 hub controller lets it talk to the camera, storage, and networking hardware at the same time. Power comes from a 5 V supply with the 18650 cell wired through the board's built-in power management, so it keeps filming through an outage. One gotcha Mayer hit: intermittent network dropouts turned out to be a small voltage sag under heavy processor load. Nudging the supply output back up fixed it, a good pin-level debugging lesson for anyone chasing flaky Wi-Fi on an SBC.

Print, mount, and manage the heat

Everything sits inside a Hammond aluminum case, with 3D-printed ASA brackets holding the camera module in place because ASA shrugs off the heat trapped in a sealed box. A heatsink bolted to the aluminum housing turns the entire case into a passive heat spreader, which also stops frost from forming on the front glass in cold weather. If you want to build your own, the full write-up and bill of materials are on the Hackster project page. Grab a PocketBeagle 2, a camera module, and an 18650 holder from circuit.rocks, and you have a weekend of soldering ahead that ends with a camera you actually control.

Originally published on blog.circuit.rocks.

maker #electronics #diy #engineering #circuitrocks

Olimex PICO-EVB Turns a Raspberry Pi Pico Into a Mini-PLC

circuitrocks — Mon, 20 Jul 2026 22:07:15 +0000

Switching a real 240V load from a microcontroller is where a lot of student automation projects stall. A Raspberry Pi Pico can toggle a GPIO pin all day, but wiring that pin to a mains-powered pump, light, or motor safely means relays, optoisolation, and screw terminals you can actually trust. Olimex's new PICO-EVB carrier hands you all of that on one board, so your thesis or classroom demo can control the real world instead of just blinking an LED.

What the PICO-EVB actually is

The PICO-EVB is a carrier board that accepts any Pico-format board: a Raspberry Pi Pico, Pico 2, Pico W, Pico 2 W, or Olimex's own PICO30. You drop the Pico into 0.1"-spaced female headers, and the carrier breaks its pins out to four heavy-duty relays and four isolated inputs. For most Picos you'll need to solder male headers on first, so keep a soldering iron handy. Founder Tsvetan Usunov pitches it plainly: plug in a Pico and "you're ready to switch loads and read signals."

The specs that matter

Each of the four relays is rated 15A at 240VAC, with both normally-open and normally-closed contacts wired to screw terminals. The four optoisolated inputs accept either 3.3-30VDC or 110-220VAC, so you can read industrial sensors without frying your Pico. Every relay and input gets its own status LED for at-a-glance debugging. There's a UEXT connector for solderless I2C, SPI, or UART sensor expansion, and power can come from the Pico, a USB-C port, or a screw terminal. The board (everything except the Pico) is rated for a -45 to 85C industrial temperature range.

Build it yourself

At around 17 dollars (roughly PHP 950) plus a Pico you may already own, this is an affordable jump into real programmable-logic-controller territory. Olimex ships Arduino and MicroPython examples for reading inputs and driving relays, plus a MicroPython web-server sketch that lets a Pico W toggle outputs from any browser, and an ESPHome YAML file for dropping the board straight into Home Assistant. Design files sit under the CERN Open Hardware License v2 and the code under MIT, both on GitHub. Grab the board and source from the Hackster writeup and start with the relay example before you wire anything to mains.

Originally published on blog.circuit.rocks.

arduino #arduinoprojects #electronics #embedded #circuitrocks

Build a Fully Offline Privacy Security Camera on PocketBeagle 2

circuitrocks — Mon, 20 Jul 2026 09:07:32 +0000

Want a security camera that never phones home to a stranger's server? Here is the parts list to start: a PocketBeagle 2 single-board computer, a camera module, an 18650 lithium cell for backup power, a Microchip USB2514 hub controller, and a watertight Hammond aluminum enclosure. Add a 5V supply and a custom PCB to tie it together, and you have the bones of a camera that keeps every frame on your own bench.

What Clem Mayer built

Maker Clem Mayer designed the whole system around one goal: keep the footage offline. His camera runs person detection locally, writes recordings to local media, and stays alive through a power outage thanks to the onboard battery. No cloud account, no video stream leaving the house. Recording starts the moment someone walks into frame and stops a few seconds after they leave, so storage fills slowly instead of hoarding empty hallway footage.

How the hardware holds together

The custom PCB is the backbone. It handles power distribution, battery backup, and USB expansion on a single board, which matters because the PocketBeagle 2 has limited native interfaces. The USB2514 hub lets the board talk to the camera, storage, and networking hardware at the same time. Mayer packed everything into the sealed aluminum case and salvaged the front glass and swivel mount from a dummy camera. A heatsink bonded to the housing turns the whole enclosure into a passive heat spreader, which also keeps frost off the front window in cold weather.

One debugging gotcha is worth remembering: intermittent network dropouts turned out to be a small voltage sag under heavy processor load. Nudging the 5V supply output up fixed it. That kind of power-rail detective work is exactly what you hit on real embedded builds.

The software side

Detection runs on OpenCV plus a lightweight deep neural network on the PocketBeagle 2 itself. Footage lives locally and auto-deletes after 72 hours, though extra USB storage stretches that window as far as you want.

Build your own

Full schematics, PCB files, and the bill of materials are on the project write-up at Hackster: the complete build guide. Start with the PocketBeagle 2 and a USB camera on a breadboard, get OpenCV person detection running first, then move to the custom PCB once the software works.

Originally published on blog.circuit.rocks.

maker #electronics #diy #engineering #circuitrocks

Penn State's Paint-On Electronic Tattoos Read ECG, EEG and EMG

circuitrocks — Mon, 20 Jul 2026 04:07:25 +0000

A heart-rate patch only helps if it stays stuck to your skin, and most of them don't. Adhesive electrodes peel at the edges after a few hours, itch by the end of the day, and broadcast to everyone that you are wearing a medical device. A team at Penn State went after that comfort problem directly, and their fix reads more like body paint than hardware.

They mixed a colorful conductive ink that you brush straight onto the skin in whatever shape you like. Once it dries it behaves like an electrode, capturing the same biopotential signals clinical gear uses: ECG from the heart, EEG from the brain, and EMG from contracting muscles. In one demo the researchers pulled EMG readings off a volunteer's forearm and used them to drive a robotic prosthetic hand with no wired contact at all.

How the signal actually gets out

The tricky part is bridging soft skin to rigid electronics without the joint cracking every time you bend. Their answer is a porous silver textile that sits between the two. Wet ink soaks into the fabric and dries, forming a strong mechanical bond, and the textile stretches past 150% of its length while still letting sweat and hair through. A small clip-on module then streams the data over Bluetooth. In testing the tattoos held clean ECG traces through 12 hours of ordinary activity plus exercise, and because the electrodes are dry they may even stay artifact-free inside an MRI.

Build a simpler version yourself

You don't need a lab to experiment with biopotential sensing. An AD8232 single-lead ECG module runs on 3.3V, cleans up the roughly 1 mV heartbeat signal, and hands an analog output to any microcontroller with an ADC pin. Wire its OUT line to a GPIO on an ESP32, read it on the breadboard, and push the waveform over Bluetooth to your phone. One gotcha worth flagging: keep the electrode leads short and the board away from mains-powered gear, or 60 Hz hum will bury the trace. For a capstone or thesis, swapping stick-on pads for a conductive-ink electrode is a genuinely open research angle.

Originally published on blog.circuit.rocks.

esp32 #esp8266 #iot #wifi #circuitrocks

Run YOLO Vision Models on Raspberry Pi 5 Using Intel OpenVINO

circuitrocks — Sun, 19 Jul 2026 22:06:59 +0000

A Raspberry Pi 5 sitting next to a USB camera can now run a YOLO object-detection model at usable frame rates, with no cloud GPU and no workstation in the loop. That is the setup Intel and Ultralytics engineers just documented in a step-by-step guide for deploying YOLO on the Pi with OpenVINO, and it turns an $80 board into a real edge-vision node.

What the project actually does

OpenVINO is Intel's inference runtime, and the guide treats the Raspberry Pi as just another Arm64 Linux target instead of a special case. You point the same openvino.Core API at the board, it discovers the CPU device, reads or converts your model, and compiles it for that device. The payoff is portability. The exact code that runs on your Pi also runs on an x86 laptop or an Intel GPU machine with no rewrite. For a classroom or thesis project, that means you prototype on a laptop and deploy to the Pi without touching the inference logic.

The technical details that matter

Board choice drives everything. A Raspberry Pi 4 runs a quad-core Cortex-A72 at 1.8GHz with up to 8GB of RAM, fine for a single-camera prototype. The Raspberry Pi 5 steps up to a Cortex-A76 at 2.4GHz and up to 16GB, giving you headroom for sustained camera workloads. Two setup gotchas trip people up: run the 64-bit Raspberry Pi OS (the current image is Debian Trixie based), and install OpenVINO 2026.2.0 from PyPI inside a clean Python virtual environment. Wheels exist for CPython 3.10 through 3.13. If startup time matters, convert your model to OpenVINO IR format and turn on model caching, so a service that restarts often does not recompile on every boot.

Build it yourself

You need a Pi 4 or Pi 5, a 64-bit OS card, and a camera. Create a virtual environment, pip install openvino plus the Ultralytics package, then verify OpenVINO sees the CPU device before you load a model. Start with a modest first pipeline, then measure. On the Pi 5, budget for cooling and a solid power supply, because a Cortex-A76 pinned at inference will throttle without a heatsink or fan. The full walkthrough, including the framework comparison chart, is on the Raspberry Pi blog: https://www.raspberrypi.com/news/run-ultralytics-yolo-on-raspberry-pi-with-openvino/

Originally published on blog.circuit.rocks.

raspberrypi #rpi #singleboardcomputer #linux #circuitrocks

Raspberry Pi Zero 2 W E Ink Typewriter: A Focused WriterDeck

circuitrocks — Sun, 19 Jul 2026 09:07:06 +0000

A blinking cursor in a browser tab is where good writing goes to die. Notifications, open chats, and a dozen other tabs all compete for attention that should be going onto the page. That is the problem a "writerDeck" solves: a single-purpose machine that boots straight into a text editor and does nothing else. Jamie of Myth Made wanted one that also looked the part, so she built an E Ink typewriter that pairs the calm of an ePaper screen with the charm of a vintage desk machine.

Jamie followed the writerDeck idea but gave it a typewriter body she designed from scratch in CAD over several weeks. The keyboard started life as a cheap USB board; she reused the PCB and switches, then made round-top keycaps to echo old typewriter keys. To label them she painted the caps, laser-engraved the wet paint so it fused into the plastic, and wiped off the excess. The shell was printed in sections, bonded with an ABS-acetone slurry, sanded smooth, and finished in a green paint job.

What is driving it

The electronics follow the open-source Zerowriter blueprint. At the center sits a Raspberry Pi Zero 2 W, a quad-core board small enough to hide inside the case, feeding a Waveshare ePaper display over the Pi's SPI pins. A rechargeable 3.7V lithium cell keeps it portable. The Zerowriter software already handles the slow refresh quirks of E Ink, and Jamie extended it (with some AI help) to add cursor movement and copy/paste. On the sides she wired a rotary encoder that doubles as a menu button and scroll wheel, plus a six-digit seven-segment LED display that shows the live word count. A hand-cranked rack-and-pinion even lifts the screen out of the body like paper rolling out of a typewriter.

Build your own version

You can get the core running for far less than a commercial e-reader. The shortlist is a Raspberry Pi Zero 2 W, a Waveshare 4.2-inch or larger ePaper module, a USB or hand-wired mechanical keyboard, a LiPo cell with a charge board, and a rotary encoder. The encoder needs two GPIO pins plus a common ground, and the ePaper hat drops onto the SPI header, so almost none of it requires soldering if you buy the HAT version. Start with the Zerowriter software on a fresh Raspberry Pi OS Lite image, confirm the display refreshes, then add the encoder and word-count readout once the basics work. The full build notes are on the original Hackster writeup.

Originally published on blog.circuit.rocks.

raspberrypi #rpi #singleboardcomputer #linux #circuitrocks

Thread-Based Circuits Sew Health Monitoring Into Your Clothes

circuitrocks — Sun, 19 Jul 2026 04:07:27 +0000

A single strand of thread, coated and stitched into a shirt, can track your breathing while you wear it. No wristband, no charger to remember, no rigid gadget clipped to your belt. Researchers at Tufts University have built working circuits directly onto textile threads, and the result behaves more like fabric than like the electronics you are used to.

Their thread carries complete analog circuits: transistors, resistors, sensors, and amplifiers, all riding on one strand instead of a flat circuit board. Because the components sit on the thread itself, the circuit can bend, twist, coil, and stretch while it keeps working. In one demo a thread near the temple picked up blinking. Another placed near the diaphragm followed breathing patterns and respiration rate, close enough to fabric that a wearer would forget it was there.

How the thread becomes a circuit

The wiring is a thin thread coated in gold. Tiny flexible organic transistors attach straight onto it, and conductive polymer coatings form the electrical pathways and passive parts like resistors. A soft material called a eutectogel acts as each transistor's gate dielectric, steering current the way the gate on a normal MOSFET would. Unlike the hydrogels most flexible electronics use, eutectogels do not dry out, and they partially heal themselves: bring a torn section back together, add gentle heat, and both the mechanical strength and the electrical performance return. The on-thread amplifier lifts the tiny signal from a stretch sensor with no rigid board anywhere in the loop.

Build your own e-textile version

You will not spin gold thread at home, but sewable electronics is very approachable for a classroom or capstone project. Start with a LilyPad-style board, which runs its ATmega328 at 8 MHz on 3.3V from a 3V sewable coin cell, and stitch your traces with conductive thread instead of soldering wire. A few gotchas to plan for:

Conductive thread has real resistance, a few ohms per inch, so keep runs short and never let two bare traces cross.
Sew a stretch or bend sensor into a sleeve and read it on an analog GPIO pin to log movement or breathing.
Seal every knot with a dab of clear nail polish so it will not fray or short after a wash.

Read the original write-up on Hackster at https://www.hackster.io/news/your-next-health-tracker-could-be-a-piece-of-string-b6a43091534d, then grab conductive thread and a LilyPad from circuit.rocks and prototype a breathing sensor on an old t-shirt this weekend.

Originally published on blog.circuit.rocks.

sensors #iot #electronics #dataacquisition #circuitrocks