The hottest Firmware Substack posts right now

A physical Game of Life was built as a 17×17 grid of illuminated mechanical switches driven by an AVR microcontroller, using row/column multiplexing and transistor drivers to handle the LEDs.
Row scanning gives each LED a low duty cycle, so the design uses high peak currents, series resistors, MOSFETs/P-channel transistors, and firmware safeguards like a blackout window and watchdog to avoid thermal or software-induced damage.
Mechanical switches provide a tactile, editable playfield with an analog speed knob, but they are the main cost driver; cheaper or fancier options (touchscreens, flip-dots) trade off price, feel, and complexity.

On the ESP32-S3, compiling with -Os (optimize for size) gave better results than using -O2 (optimize for speed).
Binary size can matter more than you might expect on constrained microcontrollers, so smaller builds can be preferable.
This challenges the common assumption that higher optimization levels focused on speed are always the best choice for embedded targets.

An ESP32 microcontroller can be turned into a USB webcam that works as a thermal/infrared camera.
The device captures infrared/thermal images instead of normal visible-light video, letting you see heat signatures.
Full DIY build instructions and details are available online for anyone who wants to reproduce the project.

A problem got fixed even though the reason for the fix is unclear.
The method used is discouraged and not something others should copy.
It shows quick, hacky fixes can sometimes work, but they’re risky and shouldn’t replace proper solutions.

The new prototype is now in production after some delays, showing the importance of taking action despite fears.
The process of sending the boards off involved some challenges with component availability, requiring adjustments.
Future plans involve exploring software options, experimenting with hardware possibilities, and considering 3D printed cases.

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Don't rely on printf() or GPIO pin waggling as your primary way to debug ESP32 projects.
There are better, more reliable debugging approaches and tools you should use instead of ad‑hoc prints and pin toggles.
Learn a structured debugging process — the "six stages of debugging" (covered in the video and short blog post) can help you diagnose problems more effectively.

The LSM6DS3 sensor combines both accelerometer and gyroscope functions to measure motion and orientation. It's great for detecting movement but can have accuracy issues based on its environment.
Using fusion mode can help to reduce drift over time by combining data from both sensors, allowing for more stable readings. This means your measurements can be more reliable during movement.
The project is open source, meaning you can easily access and modify the code for your own use. You can load 3D models of your PCBs and see them in real time, which adds a fun interactive element to the testing process.

The maker community stayed curious and playful through 2025, prioritizing exploration, learning, and hands-on experimentation even when projects got messy.
Practical, clever hacks and tools stood out — from ESP32 USB JTAG debugging and Raspberry Pi test benches to multicolor 3D printer mods, tiny spectrum analyzers, DIY chips, and firmware hacks.
The year closed with community momentum and useful opportunities, like discounted CE certification for open-source hardware, encouraging makers to keep building into 2026.

Many school districts rushed to purchase Chromebooks for students during the COVID-19 pandemic, leading to a potential tsunami of e-waste as these devices near the end of their support life.
Extending the lifespan of Chromebooks could save school districts billions of dollars and help reduce the environmental impact of replacing these devices.
Manufacturers need to make Chromebooks more repairable by offering replacement parts and designing devices that support repairability, which could make repair more economical and sustainable.