[Austin Blake] sitting on line follower cart in garage

Honey, I Blew Up The Line Follower Robot

May 21, 2025 by Heidi Ulrich 6 Comments

Some readers may recall building a line-following robot during their school days. Involving some IR LEDs, perhaps a bit of LEGO, and plenty of trial-and-error, it was fun on a tiny scale. Now imagine that—but rideable. That’s exactly what [Austin Blake] did, scaling up a classroom robotics staple into a full-size vehicle you can actually sit on.

The robot uses a whopping 32 IR sensors to follow a black line across a concrete workshop floor, adjusting its path using a steering motor salvaged from a power wheelchair. An Arduino Mega Pro Mini handles the logic, sending PWM signals to a DIY servo. The chassis consists of a modified Crazy Cart, selected for its absurdly tight turning radius. With each prototype iteration, [Blake] improved sensor precision and motor control, turning a bumpy ride into a smooth glide.

The IR sensor array, which on the palm-sized vehicle consisted of just a handful of components, evolved into a PCB-backed bar nearly 0.5 meters wide. Potentiometer tuning was a fiddly affair, but worth it. Crashes? Sure. But the kind that makes you grin like your teenage self. If it looks like fun, you could either build one yourself, or upgrade a similar LEGO project.
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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 John Elliot V 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.

A high level pictorial schematic of the basement monitor.

Making Sure The Basement Stays Dry With An ESP8266

May 17, 2025 by John Elliot V 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.

Smart Terrarium Run By ESP32

May 15, 2025 by Lewin Day 8 Comments

A terrarium is a little piece of the living world captured in a small enclosure you can pop on your desk or coffee table at home. If you want to keep it as alive as possible, though, you might like to implement some controls. That’s precisely what [yotitote] did with their smart terrarium build.

At the heart of the build is an ESP32 microcontroller. It’s armed with temperature and humidity sensors to detect the state of the atmosphere within the terrarium itself. However, it’s not just a mere monitor. It’s able to influence conditions by activating an ultrasonic fogger to increase humidity (which slightly impacts temperature in turn). There are also LED strips, which the ESP32 controls in order to try and aid the growth of plants within, and a small OLED screen to keep an eye on the vital signs.

It’s a simple project, but one that serves as a basic starting point that could be readily expanded as needed. It wouldn’t take much to adapt this further, such as by adding heating elements for precise temperature control, or more advanced lighting systems. These could be particularly useful if you intend your terrarium to support, perhaps, reptiles, in addition to tropical plant life.

Indeed, we’ve seen similar work before, using a Raspberry Pi to create a positive environment to keep geckos alive! Meanwhile, if you’re cooking up your own advanced terrarium at home, don’t hesitate to let us know.

LED Layer Makes Plywood Glow

May 14, 2025 by Tyler August 4 Comments

Plywood is an interesting material: made up of many layers of thin wood plys, it can be built up into elegantly curved shapes. Do you need to limit it to just wood, though? [Zach of All Trades] has proved you do not, when he embedded a light guide, LEDs, microcontrollers and touch sensors into a quarter inch (about six millimeter) plywood layup in the video embedded below.

He’s using custom flexible PCBs, each hosting upto 3 LEDs and the low-cost PY32 microcontroller. The PY32 drives the RGB LEDs and handles capacitive touch sensing within the layup. In the video, he goes through his failed prototypes and what he learned: use epoxy, not wood glue, and while clear PET might be nice and bendy, acrylic is going to hold together better and cuts easier with a CO2 laser. Continue reading “LED Layer Makes Plywood Glow” →

A Brain Transplant For A Philips Smart Lamp

May 14, 2025 by Tyler August 25 Comments

As the saying goes, modern problems require modern solutions. When the modern problem is that your smart light is being hijacked by the neighbors, [Wejn]’s modern solution is to reverse engineer and replace the mainboard.

The light in question is a Phillips Hue Ambiance, and [Wejn]’s excellently-documented six part series takes us through the process of creating a replacement light driver. It’s a good read, including reverse-engineering the PWM functions to get the lights to dim exactly like stock, and a dive into the Zigbee protocol so his rebuild light could still talk to the Philips Hue hub. The firmware [Wejn] wrote for the ESP32C6 he chose to use for this project is on GitHub, with the PCB in a second repo.

We want to applaud [Wejn] for his excellent documentation and open-sourcing (the firmware and PCB are under GPL v3). Not only do we get enough information to replicate this project perfectly if we so choose, but by writing out his design process, [Wejn] gives everyone reading a good head start in doing something similar with other hardware. Even if you’re scratching your head wondering why a light switch isn’t good enough anjymore, you have to appreciate what [Wejn] is offering the community.

We’ve covered domestic brain transplants in the past — which is easier in this sort of light than the close confines of a smart bulb. If you’re still wondering why not just use a light switch, perhaps you’d rather hack the light to run doom instead.

Before you go, can we just take a moment to appreciate how bizarre the world has become that we have a DOOM-capable computer to run fancy light fixture? If you’re using what might have been a decent workstation in days of yore to perform a painfully mundane task, let us know on the tips line.

Exploring The RP2350’s UART-Bootloader

May 11, 2025 by Tyler August 12 Comments

The RP2350 has a few advantages over its predecessor, one of which is the ability to load firmware remotely via UART, as [Thomas Pfister] has documented on his blog and in the video below.

[Thomas] had a project that needed more PWM than the RP2350 could provide, and hit upon the idea of using a second RP2350 as a port expander. Now, one could hard-code this, but dealing with two sets of firmware on one board can be annoying. That’s where the UART bootloader comes in: it will allow [Thomas] to program the port-expander RP2350 using the main microcontroller. Thus he only has to worry about one firmware, speeding up development.

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