OOKLONE: a cheap RF 433.92MHz OOK frame cloner
Fabien Le Mentec built a pocket device that listens to and clones 433.92MHz OOK frames, automating the tedious reverse engineering of cheap wireless outlets. The prototype uses a Moteino with an RFM69 to sample demodulated OOK data, stores pulse durations in SRAM, and replays frames; the code and hardware notes are available on GitHub along with limitations and next steps.
Reverse engineering wireless wall outlets
Fabien Le Mentec reverse engineers a cheap set of wireless wall outlets to add them to his BANO home automation while avoiding uncertified mains hardware. He uses PCB inspection to identify a Holtek MCU and RF83C, captures 433.92 MHz OOK signals with an RTL-SDR and ookdump, then replays commands using an RFM22 in direct mode controlled by an ATmega328P. The post explains frame structure and links to a working GitHub implementation.
A wireless door monitor based on the BANO framework
Fabien Le Mentec built a battery-powered wireless door monitor and a reusable node framework called BANO to monitor doors across seven floors without wired links. The post highlights BANO's 17-byte key,value protocol, the node runtime that enables wake-on-interrupt low-power operation, and practical RF choices like the NRF905 plus a 330 µF cap to handle coin-cell transmission peaks. It includes source, PCB, and base station notes.
Using a RTLSDR dongle to validate NRF905 configuration
Fabien Le Mentec wanted to be sure his nRF905 radio link was configured correctly before trusting it across seven floors. Instead of guessing, he used a cheap RTLSDR dongle, rtl_fm, and a small custom decoder to inspect the 433 MHz traffic directly. The result was a practical way to validate packet framing, Manchester coding, and signal strength without relying only on the radio module’s own feedback.
How to Arduino - a video toolbox
Lonnie Honeycutt is kicking off a practical Arduino video series aimed at hobbyists who want the fastest, simplest way to get things working. The first few lessons cover the Arduino IDE, breadboards, a 16x2 LCD, servos, potentiometers, and analogRead. He also shares a behind-the-scenes look at his multi-camera filming setup and how it helps him focus on the project instead of the shot.
Introduction to Microcontrollers - Driving WS2812 RGB LEDs
Mike Silva walks through a practical, cycle-counted AVR assembly implementation to bit-bang WS2812B RGB LEDs from an 8MHz AVR, hitting the chip's tight 1.25µs-per-bit timing. The post breaks down the WS2812B self-clocked protocol and GRB byte order, explains register and calling-convention choices, and includes a complete C example plus power-consumption warnings for driving LED strips.
Introduction to Microcontrollers - Button Matrix & Auto Repeating
Wiring every button to its own GPIO gets expensive fast, so Mike Silva shows how to read a 4x4 keypad with only eight pins using matrix scanning. He then builds the raw scan into a debounced state machine, adds auto-repeat, and even extends it to a two-stage repeat rate. The result is a practical, code-heavy walkthrough for turning a keypad into clean button events on AVR and STM32.
Energia - program a TI MSP430 using Arduino sketches
Energia brings Arduino simplicity to TI's MSP430, turning a fiddly toolchain into a sketch-based workflow you already know. Lonnie Honeycutt walks through why the Launchpad is a great low-cost dev option, outlines supported MSP430 families and caveats like 3.3 volt I/O, and shows a Halloween LED jack-o-lantern sketch to prove how quickly you can get blinking LEDs.
Embedded Systems - free EdX course by UT-Austin!
Lonnie shares a free edX Embedded Systems course from UT Austin that teaches hands-on firmware using the TI Tiva Launchpad. The class centers on practical projects, culminating in an arcade-style shooter built with an 80 MHz ARM Cortex-M4 board and inexpensive peripherals like the Nokia 5110 display. It’s a low-cost path to move from hobby tools to industry-style microcontroller development.
Introduction to Microcontrollers - Buttons and Bouncing
Mechanical buttons lie to your microcontroller, producing bounces and occasional noise that look like multiple presses. Mike Silva walks through practical ways to represent buttons, simple and robust software debounce strategies, and how to convert states into single-use events. The post includes ready-to-use C patterns: N-sample filters, shift-accumulator filtering, per-button data structures, and keypad debouncing examples.
Introduction to PIC Timers
The fourth in a series of five posts looks at 8-bit PIC hardware timers. After a review of basic timer functionality, the Timer0 module operation and configuration is reviewed and a basic application implemented using Timer0 to blink external LEDs at a frequency of 0.5Hz.
OOKLONE: a cheap RF 433.92MHz OOK frame cloner
Fabien Le Mentec built a pocket device that listens to and clones 433.92MHz OOK frames, automating the tedious reverse engineering of cheap wireless outlets. The prototype uses a Moteino with an RFM69 to sample demodulated OOK data, stores pulse durations in SRAM, and replays frames; the code and hardware notes are available on GitHub along with limitations and next steps.
What does it mean to be 'Turing complete'?
The term "Turing complete" describes all computers and even some things we don't expect to be as powerful as a typical computer. In this article, I describe what it means and discuss the implications of Turing completeness on projects that need just a little more power, on alternative processor designs, and even security.
Introduction to Microcontrollers - More On Interrupts
Interrupts are powerful but dangerous, and Mike Silva breaks down how they actually behave on microcontrollers and why they can corrupt data. This post explains latched flags, pending and priority behavior, ISR nesting, and common read-modify-write hazards, then shows practical fixes like targeted interrupt masking and using atomic GPIO hardware so you can stop chasing sporadic bugs.
Choosing a Microcontroller for Your Vehicle
Picking the right microcontroller can make or break an autonomous vehicle project, and this post gives a practical checklist to help. It walks through voltage and power needs, memory and IO planning, cost and availability tradeoffs, and when to step up from an 8-bit MCU to a 32-bit controller or single-board computer. Real-world board examples illustrate the choices.
Slew Rate Limiters: Nonlinear and Proud of It!
Slew-rate limits are a small nonlinear detail that often decides whether a controller behaves nicely or wrecks hardware. Jason Sachs walks through why slew limits appear in electronics and actuators, then shows two practical digital ways to impose limits: constraining input increments and constraining input around the output. He compares performance on underdamped second-order systems, gives closed-form intuition for overshoot, and demonstrates simulations with scipy and ODE solvers.
AI at the Edge - Can I run a neural network in a resource-constrained device?
AI at the edge is no longer science fiction, it can run on tiny, resource-constrained devices like Arm Cortex-M4 and M7 microcontrollers. This post introduces inference-only neural networks on MCUs, explains why edge AI matters for power, latency, and privacy, and points to practical toolchains such as STM32Cube.AI, Arm NN, and AWS Greengrass to get started quickly.
A wireless door monitor based on the BANO framework
Fabien Le Mentec built a battery-powered wireless door monitor and a reusable node framework called BANO to monitor doors across seven floors without wired links. The post highlights BANO's 17-byte key,value protocol, the node runtime that enables wake-on-interrupt low-power operation, and practical RF choices like the NRF905 plus a 330 µF cap to handle coin-cell transmission peaks. It includes source, PCB, and base station notes.
nRF5 to nRF Connect SDK migration via DFU over BLE
This writeup contains some notes on how I was able to migrate one of my clients projects based on the nRF5 SDK, to nRF Connect SDK (NCS) based firmware, via a DFU to devices in the field over BLE.
Essential Elements to choose a right Processor
Choosing the right processor can feel overwhelming, especially after a project with many viable parts. In this post Sathyanarayana Hadadi condenses practical criteria into a usable checklist for embedded designers, covering speed, hardware accelerators, peripherals, memory, power, security, availability, and tooling. Read on to turn a long shortlist into a confident selection and avoid costly redesigns.
Getting Started With Zephyr: Writing Data to EEPROM
In this blog post, I show how to implement a Zephyr application to interact with EEPROM. I show how the Zephyr device driver model allows application writers to be free of the underlying implementation details. Unfortunately, the application didn't work as expected, and I'm still troubleshooting the cause.
Simulating Your Embedded Project on Your Computer (Part 2)
Having a simulation of your embedded project is like having a superpower that improves the quality and pace of your development ten times over! To be useful, though, it can't take longer to develop the simulation than it takes to develop the application code and for many simulation techniques "the juice isn't worth the squeeze"! In the last article, I showed you how to use the terminal (i.e. printf/getchar) to easily make a completely functional simulation. In this article, we'll take simulation to the next level, either in terms of realism (by using virtual hardware) or in terms of user experience (by using a GUI to simulate our hardware, instead of using the terminal).
NULL pointer protection with ARM Cortex-M MPU
This post explains how you can set up the ARM Cortex-M MPU (Memory Protection Unit) to protect thy code from dragons, demons, core dumps, and numberless other foul creatures awaiting thee after thou dereference the NULL pointer.
nRF5 to nRF Connect SDK migration via DFU over BLE
This writeup contains some notes on how I was able to migrate one of my clients projects based on the nRF5 SDK, to nRF Connect SDK (NCS) based firmware, via a DFU to devices in the field over BLE.
What does it mean to be 'Turing complete'?
The term "Turing complete" describes all computers and even some things we don't expect to be as powerful as a typical computer. In this article, I describe what it means and discuss the implications of Turing completeness on projects that need just a little more power, on alternative processor designs, and even security.
Improving the Reload2 active load
Fabien Le Mentec takes a low-cost Reload2 active load and turns it into a programmable test tool. By swapping the manual setpoint for a Teensy 3.1 DAC and replacing the op-amp with a chopper amplifier, he gets software-controlled current profiles and lowers the minimum load current to about 7 mA. It is a practical hack for testing power supplies and Ethernet-powered boards under realistic startup and sleep conditions.
Introduction to PIC Timers
The fourth in a series of five posts looks at 8-bit PIC hardware timers. After a review of basic timer functionality, the Timer0 module operation and configuration is reviewed and a basic application implemented using Timer0 to blink external LEDs at a frequency of 0.5Hz.
Embedded Systems - free EdX course by UT-Austin!
Lonnie shares a free edX Embedded Systems course from UT Austin that teaches hands-on firmware using the TI Tiva Launchpad. The class centers on practical projects, culminating in an arcade-style shooter built with an 80 MHz ARM Cortex-M4 board and inexpensive peripherals like the Nokia 5110 display. It’s a low-cost path to move from hobby tools to industry-style microcontroller development.
Getting Started with (Apache) NuttX RTOS Part 2 - Looking Inside and Creating Your Customized Image
This hands-on guide peels back the NuttX source tree and shows how to assemble a tailored firmware image. You will learn what each top-level directory does, how to enable apps with menuconfig and search tricks to resolve dependencies, and how to save a defconfig as a reusable board profile so you can rebuild the same image without repeating configuration steps.
STM32 VS Code Extension Under The Hood
ST's STM32 VS Code extension hides useful CMake projects and VS Code tasks behind a friendly UI, but understanding what it generates lets you bend it to your needs. This video peels back the layers to show the generated CMake files, how to modify them, how to add a VS Code-invokable flash task, and how to enable C++ support alongside C. The STM32 F0 example and flash task are available on GitHub.
