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.
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.
MSP430 LaunchPad Tutorial - Part 4 - UART Transmission
Want to stream sensor or debug data from an MSP430 LaunchPad to a PC or Bluetooth module? Enrico swaps in an MSP430G2553 and shows how to configure SMCLK, P1 pin multiplexing, and UCA0 baud/dividers (with modulation) to approximate 115200 baud. The post also walks through interrupt-driven RX/TX handling and a low-power wait loop that sends a "Hello World" reply on demand.
Endianness and Serial Communication
A single wrong byte order can cost you a day of debugging, and Stephen Friederichs walks through how to avoid that when sending multi-byte data over a byte-oriented serial link. He demonstrates an ATmega328P sending 16-bit ADC readings, capturing raw bytes with RealTerm, and plotting with Octave, showing how swapped endianness can produce plausible but incorrect results. The post gives practical steps to capture, test, and verify byte order.
Help, My Serial Data Has Been Framed: How To Handle Packets When All You Have Are Streams
Framing byte streams is easier to get wrong than you think, and a bad scheme can leave your embedded device acting on the wrong packet. Jason Sachs walks through common plaintext and binary framing approaches, explains why CRCs alone can still permit false resynchronization, and demonstrates COBS as a simple, low-overhead byte-stuffing method that prevents delimiter collisions and guarantees resynchronization.
STM32 B-CAMS-OMV Walkthrough
Want to prototype embedded vision quickly? This walkthrough shows how the STM32 B-CAMS-OMV camera module pairs with the STM32H747I-DISCO discovery kit and the FP-AI-VISION1 function pack to get you running in minutes. The video covers the camera connection interface, key software functions to control and process data, and the ISP features that let image processing run inside the camera. The STM32 H7 project with B-CAMS-OMV drivers is available on GitHub.
Elliptic Curve Key Exchange
Elliptic Curve key exchange gives a fresh secret for every session so past messages stay safe even if one key is discovered. This post walks through an ElGamal-style ephemeral exchange and the MQV protocol, showing how MQV mixes static and random keys to provide mutual authentication and forward secrecy. It also explains how MQV can be implemented using only curve operations to save FPGA area and why erasing ephemeral values matters.
Public speaking
Presenting technical work is unavoidable for embedded engineers, but few get formal training on how to do it well. This post gives practical, low-overhead tactics: use a single person focus to steady nerves, build a bullet point memory palace to guide remarks, time your talk with about 100 words per minute, avoid reading slides, and rehearse on camera. These tips make talks clearer and less stressful.
Elliptic Curve Digital Signatures
Elliptic curve digital signatures deliver compact, strong message authentication by combining a hash of the message with elliptic curve point math. This post walks through the standard sign and verify equations, showing why recomputing a point R' yields the same x coordinate only when the hash matches. It also explains the Nyberg-Rueppel alternative that removes modular inversion and an FPGA-friendly trick of transmitting point D to avoid integer modular arithmetic.
The Asimov Protocol
While the Internet is choke-full of explanations of basic data communication protocols, very little is said about the higher levels of packing, formatting, and exchanging information in a useful and practical way. This less-charted land is still fraught with strange problems, whose solutions may be found in strange places – in this example, a very short, 60 years old Science Fiction story.
When a Mongoose met a MicroPython, part II
In the first part of this blog, we introduced this little framework to integrate MicroPython and Cesanta's Mongoose; where Mongoose runs when called by MicroPython and is able to run Python functions as callbacks for the events you decide in your event handler. Now we add MQTT to the equation, so we can subscribe to topics and publish messages right from MicroPython.
Bellegram, a wireless DIY doorbell that sends you a Telegram message
A wireless button that uses the M5 STAMP PICO and Mongoose to send a Telegram message when pressed. The code is written in C
Elliptic Curve Cryptography - Multiple Signatures
Point pairings let you compress many independent elliptic-curve signatures into a single verification, reducing n checks to one. This post explains how each signer derives a coefficient from the ordered list of public keys, aggregates signatures on the base group and public keys on the extension group, and verifies everything with one pairing computation. It also flags practical cautions like key validation and agreed ordering.
The Asimov Protocol
While the Internet is choke-full of explanations of basic data communication protocols, very little is said about the higher levels of packing, formatting, and exchanging information in a useful and practical way. This less-charted land is still fraught with strange problems, whose solutions may be found in strange places – in this example, a very short, 60 years old Science Fiction story.
Public speaking
Presenting technical work is unavoidable for embedded engineers, but few get formal training on how to do it well. This post gives practical, low-overhead tactics: use a single person focus to steady nerves, build a bullet point memory palace to guide remarks, time your talk with about 100 words per minute, avoid reading slides, and rehearse on camera. These tips make talks clearer and less stressful.
