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.

Self-Hosting A Cluster On Old Phones

April 9, 2025 by 35 Comments

The phones most of us carry around in our pockets every day hold a surprising amount of computing power. It’s somewhat taken for granted now that we can get broadband in our hands in most places; so much so that when one of these devices has reached the end of its life it’s often just tossed in a junk drawer even though its capabilities would have been miraculous only 20 years ago. But those old phones can still be put to good use though, and [Denys] puts a few of them back to work running a computing cluster.

Perhaps the most significant flaw of smartphones, though, is that most of them are locked down so much by their manufacturers that it’s impossible to load new operating systems on them. For this project you’ll need to be lucky enough (or informed enough) to have a phone with an unlockable bootloader so that a smartphone-oriented Linux distribution called postmarketOS can be installed. With this nearly full-fledged Linux distribution to work from, the phones can be accessed by ssh and then used to run Kubernetes for the computing cluster. [Denys] has three phones in his cluster that run a few self-hosted services for him.

[Denys] also points out in his guide that having a phone that can run postmarketOS might save some money when compared to buying a Raspberry Pi to run the same service, and the phones themselves can often be more powerful as well. This is actually something that a few others have noted in the past as well. He’s gone into a considerable amount of detail on how to set this up, so if you have a few old smartphones gathering dust, or even those with broken screens or other physical problems where the underlying computing resources are still usable, it’s a great way to put these machines back to work.

Thanks to [mastro Gippo] for the tip!

Hackaday Podcast Episode 270: A Cluster Of Microcontrollers, A Rocket Engine From Scratch, And A Look Inside Voyager

May 10, 2024 by No comments

Join Hackaday Editors Elliot Williams and Tom Nardi as they get excited over the pocket-sized possibilities of the recently announced 2024 Business Card Challenge, and once again discuss their picks for the most interesting stories and hacks from the last week. There’s cheap microcontrollers in highly parallel applications, a library that can easily unlock the world of Bluetooth input devices in your next project, some gorgeous custom flight simulator buttons that would class up any front panel, and an incredible behind the scenes look at how a New Space company designs a rocket engine from the ground up.

Stick around to hear about the latest 3D printed gadget that all the cool kids are fidgeting around with, a brain-computer interface development board for the Arduino, and a WWII-era lesson on how NOT to use hand tools. Finally, learn how veteran Hackaday writer Dan Maloney might have inadvertently kicked off a community effort to digitize rare documentation for NASA’s Voyager spacecraft.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download your very own copy of the podcast right about here.

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256-Core RISC-V Megacluster

May 7, 2024 by 16 Comments

Supercomputers are always an impressive sight to behold, but also completely unobtainable for the ordinary person. But what if that wasn’t the case? [bitluni] shows us how it’s done with his 256-core RISC-V megacluster.

While the CH32V family of microcontrollers it’s based on aren’t nearly as powerful as what you’d traditionally find in a supercomputer, [bitluni] does use them to demonstrate a property of supercomputers: many, many cores doing the same task in parallel.

To recap our previous coverage, a single “supercluster” is made from 16 CH32V003 microcontrollers connected to each other with an 8-bit bus, with an LED on each and the remaining pins to an I/O expander. The megacluster is in turn made from 16 of these superclusters, which are put in pairs on 8 “blades” with a CH32V203 per square as a bridge between the supercluster and the main 8-bit bus of the megacluster, controlled by one last CH32V203.

[bitluni] goes into detail about designing PCBs that break KiCad, managing an overcrowded bus with 16 participants, culminating in a mesmerizing showcase of blinking LEDs showing that RC oscillators aren’t all that accurate.

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A RISC-V Supercluster For Very Low Cost

April 19, 2023 by 22 Comments

As ARM continues to make inroads in the personal computing space thanks to its more modern and streamlined instruction set architecture (ISA) and its reduced power demands especially compared to x86 machines, the main reason it continues to become more widespread is how easy it is to get a license to make chips using this ISA. It’s still not a fully open source instruction set, though, so if you want something even more easily accessible than ARM you’ll need to find something like these chips running the fully open-source RISC-V ISA and possibly put them to work in a custom supercluster.

[bitluni] recently acquired a large number of CH32V003 microcontrollers and managed to configure them all to work together in a cluster. The entire array is only $2 (not including all of the other components attached to the board) so a cluster of arbitrary size is potentially possible. [bitluni] built a four-layer PCB for this project with an 8-bit bus so the microcontrollers can communicate with each other. Each chip has its own ADC and I/O that are wired to a set of GPIO pins on the sides of the board. The build is rounded out with a USB interface for programming and power.

There were a few quirks to get this supercluster up and running, including some issues with the way the reset and debug pins work on these specific microcontrollers. With some bugs like this out of the way, the entire cluster is up and running, and [bitluni] hints that his design could be easily interfaced with even larger RISC-V superclusters. As for a use for this build, sometimes clusters like these are built just to build them, but since the I/O and ADCs are accessible in theory this cluster could do anything a larger microcontroller might be able to do, only at a much lower price.

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PicoCray - Raspberry Pi Pico Cluster

Parallel Computing On The PicoCray RP2040 Cluster

April 9, 2023 by 28 Comments

[ExtremeElectronics] cleverly demonstrates that if one Raspberry Pi Pico is good, then nine must be awesome.  The PicoCray project connects multiple Raspberry Pi Pico microcontroller modules into a parallel architecture leveraging an I2C bus to communicate between nodes.

The same PicoCray code runs on all nodes, but a grounded pin on one of the Pico modules indicates that it is to operate as the controller node.  All of the remaining nodes operate as processor nodes.  Each processor node implements a random back-off technique to request an address from the controller on the shared bus. After waiting a random amount of time, a processor will check if the bus is being used.  If the bus is in use, the processor will go back to waiting.  If the bus is not in use, the processor can request an address from the controller.

Once a processor node has an address, it can be sent tasks from the controller node.  In the example application, these tasks involve computing elements of the Mandelbrot Set. The particular elements to be computed in a given task are allocated by the controller node which then later collects the results from each processor node and aggregates the results for display.

The name for this project is inspired by Seymore Cray. Our Father of the Supercomputer biography tells his story including why the Cray-1 Supercomputer was referred to as “the world’s most expensive loveseat.” For even more Cray-1 inspiration, check out this Raspberry Pi Zero Cluster.

Turing Pi 2: The Low Power Cluster

June 16, 2022 by 39 Comments

We’re not in the habit of recommending Kickstarter projects here at Hackaday, but when prototype hardware shows up on our desk, we just can’t help but play with it and write it up for the readers. And that is exactly where we find ourselves with the Turing Pi 2. You may be familiar with the original Turing Pi, the carrier board that runs seven Raspberry Pi Compute boards at once. That one supports the Compute versions 1 and 3, but a new design was clearly needed for the Compute Module 4. Not content with just supporting the CM4, the developers at Turing Machines have designed a 4-slot carrier board based on the NVIDIA Jetson pinout. The entire line of Jetson devices are supported, and a simple adapter makes the CM4 work. There’s even a brand new module planned around the RK3588, which should be quite impressive.

One of the design decisions of the TP2 is to use the mini-ITX form-factor and 24-pin ATX power connection, giving us the option to install the TP2 in a small computer case. There’s even a custom rack-mountable case being planned by the folks over at My Electronics. So if you want 4 or 8 Raspberry Pis in a rack mount, this one’s for you.
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