Author: John Elliot V

24 Articles

Various hardware components laid out on a workbench.

Working On Open-Source High-Speed Ethernet Switch

May 20, 2025 by 16 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.

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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 35 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.

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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 29 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.

A high level pictorial schematic of the basement monitor.

Making Sure The Basement Stays Dry With An ESP8266

May 17, 2025 by 38 Comments

The hack we have for you today is among our most favorite types of hack: a good, honest, simple, and well documented implementation that meets a real need. Our hacker [Solo Pilot] has sent in a link to their basement monitor.

The documentation is quite good. It’s terse but comprehensive with links to related information. It covers the background, requirements, hardware design, sensors, email and SMS alerts, software details, and even has some credits at the end.

Implementing this project would be a good activity for someone who has already made an LED flash and wants to take their skills to the next level by sourcing and assembling the hardware and then configuring, compiling, deploying, and testing the software for this real-world project.

To make this project work you will need to know your way around the Arduino IDE in order to build the software from the src.zip file included with the documentation (hint: extract the files from src.zip into a directory called AHT20_BMP280 before opening AHT20_BMP280.ino and make sure you add necessary boards and libraries).

One feature of the basement monitor that we would like to see is a periodic “everything’s okay” signal from the device, just so we can confirm that the reason we’re not getting an alarm about flooding in the basement is because there is no flood, and not because the battery ran dead or the WiFi went offline.

If you’ve recently started on your journey into where electronics meets software a project such as this one is a really great place to go next. And of course once you are proficient with the ESP8266 there are a thousand such projects here at Hackaday that you can cut your teeth on. Such as this clock and this fault injection device.

New Bismuth Transistor Runs 40% Faster And Uses 10% Less Power

May 16, 2025 by 37 Comments

Recently in material science news from China we hear that [Hailin Peng] and his team at Peking University just made the world’s fastest transistor and it’s not made of silicon. Before we tell you about this transistor made from bismuth here’s a whirlwind tour of the history of the transistor.

The Bipolar Junction Transistor (BJT, such as NPN and PNP) was developed soon after the point-contact transistor which was developed at Bell Labs in 1947. Then after Resistor-Transistor Logic (RTL) came Transistor-Transistor Logic (TTL) made with BJTs. The problem with TTL was too much power consumption.

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Internals of ding-dong doorbell.

Wireless Doorbell Extension Features Home-Wound Coil

May 16, 2025 by 12 Comments

Today in the it’s-surprising-that-it-works department we have a ding dong doorbell extension from [Ajoy Raman].

What [Ajoy] wanted to do was to extend the range of his existing doorbell so that he could hear it in his workshop. His plan of attack was to buy a new wireless doorbell and then interface its transmitter with his existing doorbell. But his approach is something others might not have considered if they had have been tasked with this job, and it’s surprising to learn that it works!

What he’s done is wrap a new coil around the ding dong doorbell’s solenoid. When the solenoid activates, a small voltage is induced into the coil. This then gets run into the wireless doorbell transmitter power supply (instead of its battery) via a rectifier diode and a filter capacitor. The wireless doorbell transmitter — having also had its push-button shorted out — operates for long enough from this induced electrical pulse to transmit the signal to the receiver. To be clear: the wireless transmitter is fully powered by the pulse from the coil around the solenoid. Brilliant! Nice hack!

We weren’t sure how reliable the transmitter would be when taken out of the lab and installed in the house so we checked in with [Ajoy] to find out. It’s in production now and operating well at a distance of around 50 feet!

Of course we’ve published heaps of doorbell hacks here on Hackaday before, such as this Bluetooth Low Energy (BLE) doorbell and this light-flashing doorbell. Have you hacked your own doorbell? Let us know on the tips line!

Continue reading “Wireless Doorbell Extension Features Home-Wound Coil” →