YouTuber bitluni has built is one of the most fascinating DIY computing projects we’ve seen in a while: a custom “GPU” made from 8,192 tiny RISC-V microcontrollers.
The project uses the ultra low-cost WCH CH570 chips, with each processor connected to its own RGB LED. The original idea was to give every pixel on a low-resolution display its own processor, creating a system where thousands of small chips all work simultaneously.
The tiny RISC-V microcontrollers are nothing like the powerful cores found inside modern graphics cards. Each one has very little memory and lacks features like floating-point and vector processing. But when you connect thousands of them together, things start to get interesting.
Of course, assembling 8,192 processors is not as simple as making a really large circuit board. Bitluni had to design custom six-layer PCB modules that plug into a central backplane. Early versions also suffered from timing and signal problems, which forced him to redesign parts of the system and give each processor its own crystal oscillator. An incredible feat In its own right.
Programming all those chips created another problem. Instead of flashing them one at a time by hand, bitluni turned a Bambu Lab 3D printer into an automated programming machine. A custom pogo-pin tool moves across the boards and uploads firmware to each chip.
The combined system also needs a large amount of power. It uses a 3,000-watt Corsair power supply, custom voltage converters and large cooling fans to keep everything running.
This homemade GPU is an experiment in parallel computing and a great example of how quickly a simple idea can grow into a massive engineering challenge.
Bitluni eventually hopes to expand the project to around 32,000 processors. His original 320×200 display idea would require roughly 64,000 chips, so this already enormous machine may only be the beginning.