HACKER Q&A
📣 aristofun

DIY computer from scratch for Kids


Is there any DIY kit that guides you from zero to building your first CPU out of basic logical units?

Ideally something that would accompany "Code" book by Petzold?

All DIY kits I see on the market are already on top of a built computer (raspberry pi or whatever).

I see much more educational value in building CPU from scratch than just plugging peripherals in and out. I hope I missed something.

  👤 smoldesu Accepted Answer ✓
It sounds kinda like you're looking for breadboards. You could build a CPU on one of those, but it's unlikely to do anything interesting and super unlikely to hold the attention of a younger audience.

The happy medium is probably using both, together. Raspberry Pis and Arduino boards all have documented GPIO you can use to leverage the power/simplicity of a modern CPU with the tactility and practicality of a physical circuit. If you're purely interested in educational value, building a CPU from scratch might not be a good idea for a young audience.

👤 evilduck
Refine the age of "kid", or at least where their abilities already are because this would be a big endeavor for most elementary school age kids.

Understanding a working electronic CPU builds on many, many abstract concepts that need foundational knowledge established first. If they're not already doing pre-algebra, they're simply not equipped mathematically to understand the value or purpose of the exercise and you'll just need to make it fun instead. For any kid under the age of 10 I would just get them https://spintronics.com/ where they can eventually build a 1-bit half adder mechanically: https://community.spintronics.com/t/1-bit-half-adder/310. Spintronics lets kids (or adults...) build intuitive understanding of electrical concepts with a set of puzzles or free play.

Beyond that, electricity might as well be magic to even huge portions of the adult population. Putting it to work to do computation even more so. If you have an especially interested and capable kid, start with basic electric circuits and build their skills up to using diodes. Then work your way up to using transistors to build an XOR gate. Then combine XOR gates to build other logical operations. Then you can build the most rudimentary of processors.

In terms of DIY kits, something like https://www.qsoshack.com/make-a-new-zx-spectrum-from-a-kit/ is about the most basic form I think you might find that results in what is recognizably "a computer" by common understanding of the term, but the leap from an XOR gate to a circuit board filled with chips is still a big one.