Author: John Elliot V

27 Articles

Intercepting And Decoding Bluetooth Low Energy Data For Victron Devices

May 26, 2025 by 9 Comments

[ChrisJ7903] has created two Ardiuno programs for reading Victron solar controller telemetry data advertised via BLE. If you’re interested in what it takes to use an ESP32 to sniff Bluetooth Low Energy (BLE) transmissions, this is a master class.

The code is split into two main programs. One program is for the Victron battery monitor and the other is for any Victron solar controller. The software will receive, dissect, decrypt, decode, and report the data periodically broadcast from the devices over BLE.

The BLE data is transmitted in Link-Layer Protocol Data Units (PDUs) which are colloquially called “packets”. In this particular case the BLE functionality for advertising, also known as broadcasting, is used which means the overhead of establishing connections can be avoided thereby saving power.

Continue reading “Intercepting And Decoding Bluetooth Low Energy Data For Victron Devices” →

Screen shot of Mongoose Wizard.

How To Build An STM32 Web Dashboard Using The Mongoose Wizard

May 25, 2025 by 1 Comment

Today from the team at Cesanta Software — the people who gave us the open-source Mongoose Web Server Library and Mongoose OS — we have an article covering how to build an STM32 web dashboard.

The article runs through setting up a development environment; creating the dashboard layout; implementing the dashboard, devices settings, and firmware update pages; building and testing the firmware; attaching UI controls to the hardware; and conclusion.

The web dashboard is all well and good, but in our opinion the killer feature remains the Over-The-Air (OTA) update facility which allows for authenticated wireless firmware updates via the web dashboard. The rest is just gravy. In the video you get to see how to use your development tools to create a firmware file suitable for OTA update.

Continue reading “How To Build An STM32 Web Dashboard Using The Mongoose Wizard” →

Two telescopes looking into the night sky.

Making A Backyard Observatory Complete With Retractable Roof

May 24, 2025 by 16 Comments

Here’s one for our astronomy geeks. Our hacker [arrow] has made their own observatory!

This particular video is a bit over ten minutes long and is basically a montage; there is no narration or explanation given, but you can watch clear progress being made and the ultimate success of the backyard facility.

Obviously the coolest thing about this building is that the roof can be moved, but those telescope mounts look pretty sexy too. About halfway through the video the concrete slab that was supporting one metal mounting pole gets torn up so that two replacements can be installed, thereby doubling the capacity of the observatory from one telescope to two.

Continue reading “Making A Backyard Observatory Complete With Retractable Roof” →

Various hardware components laid out on a workbench.

Working On Open-Source High-Speed Ethernet Switch

May 20, 2025 by 17 Comments

Our hacker [Andrew Zonenberg] reports in on his open-source high-speed Ethernet switch. He hasn’t finished yet, but progress has been made.

If you were wondering what might be involved in a high-speed Ethernet switch implementation look no further. He’s been working on this project, on and off, since 2012. His design now includes a dizzying array of parts. [Andrew] managed to snag some XCKU5P FPGAs for cheap, paying two cents in the dollar, and having access to this fairly high-powered hardware affected the project’s direction.

Continue reading “Working On Open-Source High-Speed Ethernet Switch” →

We can see the internal pads from an integrated circuit where the epoxy has been ground away.

When Repairs Go Inside Integrated Circuits

May 20, 2025 by 36 Comments

What can you do if your circuit repair diagnosis indicates an open circuit within an integrated circuit (IC)? Your IC got too hot and internal wiring has come loose. You could replace the IC, sure. But what if the IC contains encryption secrets? Then you would be forced to grind back the epoxy and fix those open circuits yourself. That is, if you’re skilled enough!

In this video our hacker [YCS] fixes a Mercedes-Benz encryption chip from an electronic car key. First, the black epoxy surface is polished off, all the way back to the PCB with a very fine gradient. As the gold threads begin to be visible we need to slow down and be very careful.

The repair job is to reconnect the PCB points with the silicon body inside the chip. The PCB joints aren’t as delicate and precious as the silicon body points, those are the riskiest part. If you make a mistake with those then repair will be impossible. Then you tin the pads using solder for the PCB points and pure tin and hot air for the silicon body points.

Once that’s done you can use fine silver wire to join the points. If testing indicates success then you can complete the job with glue to hold the new wiring in place. Everything is easy when you know how!

Does repair work get more dangerous and fiddly than this? Well, sometimes.

Continue reading “When Repairs Go Inside Integrated Circuits” →

The five picos on two breadboards and the results of image convolution.

PentaPico: A Pi Pico Cluster For Image Convolution

May 20, 2025 by 22 Comments

Here’s something fun. Our hacker [Willow Cunningham] has sent us a copy of their homework. This is their final project for the “ECE 574: Cluster Computing” course at the University of Maine, Orono.

It was enjoyable going through the process of having a good look at everything in this project. The project is a “cluster” of 5x Raspberry Pi Pico microcontrollers — with one head node as the leader and four compute nodes that work on tasks. The software for both types of node is written in C. The head node is connected to a workstation via USB 1.1 allowing the system to be controlled with a Python script.

The cluster is configured to process an embarrassingly parallel image convolution. The input image is copied into the head node via USB which then divvies it up and distributes it to n compute nodes via I2C, one node at a time. Results are given for n = {1,2,4} compute nodes.

It turns out that the work of distributing the data dwarfs the compute by three orders of magnitude. The result is that the whole system gets slower the more nodes we add. But we’re not going to hold that against anyone. This was a fascinating investigation and we were impressed by [Willow]’s technical chops. This was a complicated project with diverse hardware and software challenges and they’ve done a great job making it all work and in the best scientific tradition.

It was fun reading their journal in which they chronicled their progress and frustrations during the project. Their final report in IEEE format was created using LaTeX and Overleaf, at only six pages it is an easy and interesting read.

For anyone interested in cluster tech be sure to check out the 256-core RISC-V megacluster and a RISC-V supercluster for very low cost.

In Memory Of Ed Smylie, Whose Famous Hack Saved The Apollo 13 Crew

May 18, 2025 by 30 Comments

Some hacks are so great that when you die you receive the rare honor of both an obituary in the New York Times and an in memoriam article at Hackaday.

The recently deceased, [Ed Smylie], was a NASA engineer leading the effort to save the crew of Apollo 13 with a makeshift gas conduit made from plastic bags and duct tape back in the year 1970. [Ed] died recently, on April 21, in Crossville, Tennessee, at the age of 95.

This particular hack, another in the long and storied history of duct tape, literally required putting a square peg in a round hole. After an explosion crippled the command module the astronauts needed to escape on the lunar excursion module. But the lunar module was only designed to support two people, not three.

The problem was that there was only enough lithium hydroxide onboard the lunar module to filter the air for two people. The astronauts could salvage lithium hydroxide canisters from the command module, but those canisters were square, whereas the canisters for the lunar module were round.

[Ed] and his team famously designed the required adapter from a small inventory of materials available on the space craft. This celebrated story has been told many times, including in the 1995 film, Apollo 13.

Thank you, [Ed], for one of the greatest hacks of all time. May you rest in peace.

Header: Gas conduit adapter designed by [Ed Smylie], NASA, Public domain.