DEV Community: David Scheltema

How It's Made — Manufacturing Notecard at Scale

David Scheltema — Wed, 27 Sep 2023 16:00:00 +0000

While it is easy to get your hands on a Blues Notecard, it's not as easy to learn what it takes to manufacture one. That is... until today.

This post walks you through the factory floor as a panel of Notecards pass through each step of the manufacturing process — going from an unpopulated printed circuit board (PCB) to a working Notecard.

Before the Manufacturing Even Begins

The manufacturing process is the culmination of a huge amount of behind the scenes engineering and operational work. Before a single component is shipped to the manufacturing facility, electrical engineers must finish the PCB design and layout. This information packaged in a Gerber file format, which provides the exact design requirements for the PCB as well as the placement of the components.

Simultaneously to the work of the electrical engineers, operation engineers work with component vendors and suppliers to find the best prices, and component variants for the quantities necessary to successfully manufacture the electrical engineer's design.

It All Starts with Printed Circuit Boards

Notecard PCBs are the first component of the manufacturing process that need to be manufactured. Using a layering process of copper and FR4—a type of fire-resistant fiberglass—PCBs are built one layer at a time. Advanced PCBs like Notecard's use multiple layers of FR4 and copper to properly connect all of the components necessary to make up the final design.

Scotty from the YouTube channel Strange Parts has a great video tour of the PCB manufacturing process if you're interested in the step-by-step process.

With Notecard manufacturing a panel of eight Notecards is the smallest unit of material that goes through the line. This improves production output while reducing the time that the manufacturing line is operational.

As you can see in the unpopulated panel above, the exterior layer of the Notecard PCB consists of exposed copper pads and green areas of solder mask. Copper when heated will attract solder whereas the solder mask when heated will not.

Application of Solder Paste

The first stop on the manufacturing line is the solder paste machine. The Notecard panel is placed inside the machine and a thin metal stencil is secured over the panel.

An automated squeegee then smears a combination of solder paste and flux across the stencil depositing globs of the gooey material on the exposed copper pads. After a few passes of the squeegee, the stencil is removed and the panel is placed on a conveyer belt bound for the next step of the manufacturing line.

Optical Inspection

Before the manufacturing process goes any farther, a series of high-powered cameras inspect the dollops of solder paste and flux are correctly placed on the copper. Too much or too little solder and flux could be detrimental to the assembly process and potentially create bad solder joints between the PCB and the components.

This early inspection and anomaly detection is just one of the steps meant to ensure production efficiency and reduces costly rework later on in the manufacturing process.

Component Placement on the PCB

With fresh solder paste and flux on the PCB pads, the next step in the assembly process is component placement. It's here at the Pick-and-Place machine that automation is at its most advanced.

All the components that make up Notecard are loaded into the pick-and-place machine. Each component is packaged on a reel that loads into the pick and place machine almost like a printer cartridge to a laser printer.

The pick-and-place machine is programmed to know exactly where each component is stored on a reel as well as where each component must be placed on the PCB panel. Using a suction device on a gantry arm to lift the component and move it into position, the pick-and-place machine is able to precisely select and deposit tens of thousands of components per hour.

The speed and accuracy of these machines boggle the mind. They are simply put the backbone of the modern manufacturing line.

Soldering at Scale

With all the components placed on the globs of solder paste and flux, the only thing holding them in place is surface tension. To make a more permanent connection heat needs to be carefully applied to the panel of Notecards.

Unlike your typical handheld soldering iron where you solder one component at a time, manufacturing lines use reflow ovens to solder all of the components on one side of the PCB at once.

These high-tech ovens precisely modulate the temperature based on temperature curves input by engineers so that they heat up and cool down period is very deliberate and conforms to the temperature tolerances of the materials being reflowed.

When a reflow oven heats up, the solder paste and flux melt. The surface tension of the molten hot solder pulls the SMT component towards the copper pad on the PCB and as the oven temperatures drop, the solder cools and forms a solder joint — an electrical connection between the component and the PCB pad.

Astonishingly, reflow ovens are so precise that they are able to heat one side of a PCB and not melt the solder on the other side of the board. This allows for two-sided boards like Notecard to be reflowed in two passes — one for the top side and one for the bottom side — without any components falling off during the process.

After the solder joints are cooled, the panel of Notecards is conveyed to another automated optical inspection machine.

Automated Optical Inspection

Automated optical inspection at this point in the manufacturing line is focused on ensuring the solder joints and component placement have no defects.

As with the first round of optical inspections, it's far better to catch any problems here before the panel advances to the next stage of manufacturing.

Quality Control with a Human Touch

Quality control is the last stage of the manufacturing process where the eight Notecards are connected on one panel. Rather than rely on automation, this quality control step is performed by a manufacturing engineer.

They perform a visual inspection of all areas of the panel using large magnifying glasses as well as conduct other testing to ensure the Notecards have been properly assembled. Once approved, the panel of Notecards is ready for depanelization.

Depaneling into Single Notecards

Using an advanced router, the depaneling machine uses a bit to remove the excess FR4 material that held the eight Notecards together.

To ensure that the Notecards are not damaged during the process, the panel is loaded into a tray and a fixture is placed over the panel to guide the the router bit as the depanelization occurs.

Notecard Functional Testing

With each Notecard free from its panel and fully populated with components, it's ready for functional testing. This step ensures that the Notecard is able to power on properly and execute a series of test commands.

Once the Notecard passes the functional tests, it's off to the labeling and packaging department.

Individual Packaging and Boxing

Each Notecard is packaged individually inside a zip-locked back and placed into a large tray.

Multiple trays are stacked to snugly fit into larger shipping boxes to optimize the number of Notecards that can fit ship at a time.

What every IoT engineer needs to know about navigation: GPS, dead reckoning, cellular, Wi-Fi, and BLE

David Scheltema — Wed, 15 May 2019 21:18:31 +0000

Personal navigation has never been easier. With numerous options from GPS and cellular to Wi-Fi and Bluetooth, it can be challenging to select the right one for your product be it micromobility scooter or a fleet of logging trucks. To understand which solution is right for you, it’s helpful to have a high-level perspective on the most popular and widespread geolocation technologies.

Most geolocation solutions should start with GPS since it’s a system designed from the start to answer the question, where am I? With close to ~4-meter accuracy, it’s a no brainer to start any navigation solution here, unless of course, your use-case is underground.

Unsurprisingly, no single navigation solution is right for every product use-case or fleet deployment. What works for a micromobility scooter — a combination of GPS, cellular, and Bluetooth — would be an over-engineered solution to keep track of your keys. For that, something like Bluetooth beacons are more appropriate.

This guide will provide you with information about commonly radio technology used for navigation. After reading, you should be familiar with the different available technologies as well as a high-level awareness of the significant trade-offs between the options. In many cases, the best solution is a robust combination of technologies.

Navigation options at a glance

Determining the right option for your geolocation needs is a balancing act between the cost of the silicon and the accuracy of the location data it provides. Battery life is not covered in this overview, however, it’s good to keep in mind that the number of times you send location data from your device to the cloud will affect your battery performance. Additionally, specific radio power performance will vary by vendor and part.

GPS — The Global Positioning System (GPS) is generally the most accurate, and it can provide device location continuously. This option is moderate to high priced depending on features such as onboard RTKs. It is widely used used as the basis for any geolocation solution.

Cellular — Cellular geolocation uses known cell tower location to approximate where you are. Of course, cellular requires an active service plan and proximity to cellular towers. Cellular is predominately used as a supplement to GPS, as it lacks the accuracy to be an independent solution.

Wi-Fi — Wi-Fi is not advisable for use-cases that move a lot, but is commonly found in smartphones and laptops as a way to supplement location data or give approximate location inside of buildings using 3rd party databases of Wi-Fi access point locations.

Bluetooth 5/BLE — Great for small tracking devices such as key fobs and assets in a contained, small location. Typically deployments use a mobile phone in conjunction with Bluetooth beacons that broadcast location information.

Getting started: Weighing cost vs accuracy with GPS

Unless your use-case is subterranean, your navigation solution should begin with GPS. Thanks to smartphones, the cost of GPS modules is lower than it’s ever been, but that means there are a lot of module options to consider for your design. A helpful way to cut through the options is by balancing between unit cost and location accuracy.

As a general rule of thumb as GPS accuracy increases, so too does the cost. Inexpensive GPS modules can be purchased for under $40 and typically support UART or I2C depending on the module. More expensive, featureful GPS modules can run upwards of $200, but offer advanced capabilities like onboard RTKs. However, there’s also a bit of a middle ground. To supplement the accuracy of GPS, it’s not uncommon to see silicon vendors and product designers add additional hardware or using software to help gain higher accuracy.

Using cellular plus geofencing for robust geolocation

Cellular is typically a medium for voice and data, but you can also use it to determine approximate location. Note that a cellular-only navigation system will only provide you with your location relative to the towers your cellular device is communicating with. For more in-depth information on cellular, please see our cellular guide in the Particle docs.

Every cell tower has an identifier, and this can be looked up using Google’s Geolocation API to find where it is on the globe. This process is fast and provides a general location, usually within 4,000 meters or a couple of miles. Of course, you need a cellular signal for this to happen.

Pairing cellular connectivity with GPS-based geofencing provides a solid solution for IoT deployments that may go in and out of hard to reach places such as lumber trucks across the state of South Carolina. Particle’s customer Worthwhile combines these two technologies to provide a more robust navigation solution. Using a Particle cellular solution their open-source Geo-Bound software caches up to 2,000 GPS coordinates locally in their asset trackers memory and stores them until back in cellular range. While cellular here is not used for the navigation per se, the combinational approach of cellular plus GPS highlights a robust geolocation solution.

Improving GPS accuracy with IMU-based dead reckoning

In some situations, GPS alone cannot provide a full navigation solution. Take a fleet of scooters for example. In big cities they don’t always have a clear line of sight to the sky for GPS to work efficiently — gaining a lock on satellites takes time and consumes power, both challenging in urban environments.

By augmenting a GPS module with additional geolocational data and using techniques like dead reckoning — a navigation technique that uses information about your past position, speed, duration, and heading to calculate where you currently are — a fleet for scooters can still be found even if they can’t see the sky.

Developers use dead reckoning to supplement GPS data and help with error correction. To cost effective achieve dead reckoning, it’s not uncommon to see prototypers add an inertial measurement unit (IMU), a specialized sensor that’s packaged in a single integrated circuit, to collect information about the heading and speed information as a supplement the available GPS coordinates.

Dead reckoning works best with micromobility, specifically when tracking mobile assets around an urban area, with inexpensive non-GPS navigation devices, and it’s very accessible for DIY robotics projects.

While alone, an IMU-based dead reckoning solution isn’t recommended for high-value asset tracking, supplementing a GPS with an IMU can result in a more robust geolocation solution.

Dead reckoning in silicon: high-end GPS modules with built-in real-time kinematic engines

Land surveying and autopilot systems use GPS that include real-time kinematic engines (RTK) that perform dead reckoning inside the GPS module and boast centimeter accuracy. No extra ICs required. One example of such a module is the ublox NEO-M8P-2, which SparkFun offers in a sub-$200 breakout board.

The only problem is GPS modules with RTKs is the cost. Single quantity pricing for GPS modules with integrated RTK run upwards of $200 per unit, making them too expensive for most use-cases. Unless you’re building a centimeter accurate navigation solution like surveying a building site or autonomously assisting an autopilot system, using a GPS with RTK is over-engineering your solution.

As you can probably guess, due to the higher per unit cost, GPS modules with on-die RTKs are almost non-existent in micromobility markets, but more common in industries small measurements matter. For those undeterred by the unit price, Sparkfun electronics has an excellent primer on GPS with RTK, which also covers more advanced navigation techniques such as error correction using Radio Technical Commission for Maritime.

Wi-Fi provides supplemental navigation

Smartphones are a fantastic example of Wi-Fi supplementing other radios for geolocation. You’ve probably experienced your smartphone reminding you to turn on WI-Fi to help improve your location accuracy.

Wi-Fi assisted navigation works by using special 3rd-party API service such as Google’s Geolocation API that provides access to an enormous database of Wi-Fi access point locations. Given the scale of their enterprise and given enough data points of Wi-FI APs, the information is helpful for indoor navigation.

Problems with using Wi-Fi for navigation

One enormous challenge with using Wi-Fi as a navigational aid is that as soon as you move out of range of a Wi-Fi access point, your access to the Wi-Fi location database is lost. Smartphones do a fantastic job of obscuring this limitation since they have cellular, GPS, and Wi-Fi that work seamlessly together and require near-zero user configuration.

Much like cellular, it’s not uncommon to see early prototype projects attempting to combine Wi-Fi with an IMU to approximate a navigation system. These systems are architecturally similar to cellular plus IMU approach, but with one major drawback: limited range bound by Wi-Fi signal coverage. Without a Wi-Fi signal, there is no way for the device to connect to a cloud for dashboards, fleet management, or even access the geolocation APIs.

Don’t combine cellular and Wi-Fi to navigate unless you absolutely must

Some might think to add cellular and have a Wi-Fi and cellular solution, however, unless you’re making a smartphone, this is not an advisable approach to navigation. Adding a second radio interface such as cellular means you effectively double your power draw, increased bill of materials cost, your software integration time and rigor, and your antenna design just got a lot more complicated. Instead, a navigation solution that combines GPS with Wi-Fi is a much more appropriate path.

Bluetooth navigation handles the small stuff like finding your keys

Geolocation isn’t just about getting you from your home to office. In some use-cases, it’s about finding your misplaced keys. With a limited range of 10 meters, Bluetooth is great for helping you track down things you know are nearby but needs some help finding.

Increasingly Bluetooth 5 based devices featuring ICs like the Nordic nRF82540 found in all Particle 3rd Gen devices are used for key-finding solutions. Of particular interest to designers is the improved and descriptively named Bluetooth broadcast and beacon modes. These allow for information-rich interactions between non-paired Bluetooth devices.

For example, imagine a rideshare bike that could broadcast its battery state directly to the customer. No need to send data to the cloud, simply use a beacon mode to advertise to the rideshare app the charge level. For more on the use of Bluetooth in navigation, please see the Bluetooth SIG documentation here.

Navigating your way to the right solution for your use-case

Ultimately, the best way to understand each of these technologies is with hands-on experience. As you’ve learned, the most reliable geolocation and navigation solutions use a robust combination of radio technologies. For your own prototyping journey using a Gen 3 Particle device with an Adafruit Ultimate GPS FeatherWing is a great place to start. From there, it’s very easy to transition to an enterprise-grade module like our B Series SoM for scale.

For more on how Particle solutions can help with your geolocation and navigation products see our product suite overview or contact us and talk with an expert.

The post What every IoT engineer needs to know about navigation: GPS, dead reckoning, cellular, Wi-Fi, and BLE appeared first on Particle Blog.

Particle Workbench: supercharge your IoT development with professional tools

David Scheltema — Tue, 16 Apr 2019 15:45:42 +0000

Particle Workbench brings everything you need for IoT development into a single tool. Built on Microsoft Visual Studio Code, Workbench adds Particle-specific integrations to help make you more productive. This our most powerful, professional IoT development environment yet and starting today, it’s now generally available with our custom, cross-platform Particle installer with support for Windows, Linux (Ubuntu), and macOS — download your copy right now.

Code faster, work more efficiently, compile where you want, and say goodbye to the frustration of toolchain management. Particle Workbench includes these features right out of the box with a hassle-free installation.

Compile where you want: local or cloud
Stress-free toolchain management
Built-in version control and debugging
Flexible deployment: over-the-wire or over-the-air
Code complete with IntelliSense for Particle device libraries
Quick installation experience for Windows, Linux, and macOS

Download now and supercharge your IoT development here.

Professional tools to support your product development

When your job is to build connected solutions, it’s essential to use professional tools to help you along the way. Workbench builds upon all the great features you already love about Particle and adds even more powerful, professional tools to help you succeed.

Take for example Workbench support for cloud and local compilation. You decide where your code is built, but that’s just the beginning. Thanks to a powerful Dependency Manager, your toolchain automatically stays up-to-date no matter the compile location you choose.

Native support for git and debugging, giving you the ability to collaborate with colleagues and more efficiently troubleshoot bugs. And flexible deployment options mean you can use over-the-wire or over-the-air device flashing depending on your project requirements.

Open source, customized for you

Under the hood, Workbench takes advantage of all the great features you already know and love about Visual Studio Code and adds powerful, Particle specific capabilities.

Workbench is built on Visual Studio Code not just because it’s the experience developers love for a desktop environment, but also because of Microsoft’s commitment to open source. Visual Studio Code enables an ecosystem of customizable themes and extensions all with continued investment in powerful features that support both embedded and web development.

Get started with Workbench now

Whether you’ve tried a Workbench Developer Preview or this is your first time using the tools, the new installer is quick and doesn’t require a deep understanding of cross-compilers or development toolchains. Installation takes a few clicks of the mouse before you’ll be coding.

The installer is smart enough to check your system to determine if you have Visual Studio Code installed or not and knows what to install without any need for user action. Because of this, the installer is safe to use if you already have Visual Studio Code on your machine.

Download Particle Workbench here, dive into the docs, and let us know what you think in the community forum.

The post Particle Workbench: supercharge your IoT development with professional tools appeared first on Particle Blog.

Take your IoT career to new heights with these 3 instructive IoT video playlists

David Scheltema — Mon, 25 Mar 2019 21:10:50 +0000

I might not bring the intensity quite like Steve Ballmer famously did while chanting “Developers! Developers! Developers!” during the Microsoft 25 Anniversary Celebration in 2000, but that doesn’t mean I’m not super excited for great IoT videos for developers.

Whether you consume your videos at work or watch them with a big tub of popcorn from the comfort of your home, you can’t go wrong learning about new technical topics from instructive IoT videos. Here are three new Particle videos series that you’ll not want to miss.

Particle 101: the video series designed to help you become an IoT pro

Over the past few months, Brandon Satrom our Developer Advocate has been busy putting together a series of videos covering the essentials to help you get the most out of your Particle products. Most of the videos in the series focus on Gen 3 hardware — that’s the Argon, Boron, and Xenon — however many of the non-mesh content is applicable to Gen 2 hardware like the Photon and Electron as well.

In the latest Particle 101 video, Brandon tackles how you can use publish() and subscribe() to send messages between different devices on your local, mesh network. This video is one of seven (at the time of publication) Particle 101 videos to help you get started with IoT and Particle. Here’s the link to the full Particle 101 playlist.

Introducing Particle: Interviews with the people building Particle

Equal parts Terry Gross and Steve Ballmer, Brandon’s newest video series focuses on getting to know the people powering Particle. Get ready for great conversations and tune in live for a chance to have your question answered.

In the first episode of the series, Brandon sat down with Mohit Bhoite to talk circuits, rapid prototyping, and what it feels like to have designed every piece of Particle hardware ever released. Mohit’s interest span from low-level electrical engineering to gorgeous solder sculptures that should rightly be called art.

Twitching for more videos: here’s a live solution

A typical Twitch streaming setup from Brandon. Catch him weekly on Monday and Thursday.

And if you’re still looking for more video content, Brandon has you covered. Each Monday and Thursday he livestreams on Twitch. While you never know exactly what Brandon will be working on, his livestream is a fantastic way to get clues on what cool new things are coming next.

Most recently, Brandon upcycled an old Photon DIY brewing project to use an Argon and hacked inexpensive Drug Store remote controlled cars to use Particle Gen 3 hardware — you can see his full instructions in the annual Make: magazine board’s issue here. Here’s a quick link to the start of the brewing playlist and to the R/C car hacking.

IoT Developers, IoT Developers, IoT Developers!

Whew, it does feel good! Perhaps Ballmer was onto something here. Regardless of your intensity level, be sure to watch the videos and let us know what you think. Comments, suggestions, and constructive criticism are always welcome. Oh, and don’t miss the next Particle livestream.

Finally, be sure to share what you’re working on in the community forum or on Twitter. I can’t wait to see what you’re making.

The post Take your IoT career to new heights with these 3 instructive IoT video playlists appeared first on Particle Blog.