Show HN: I made a game where you build a CPU from logic gates (select.supply)

102 points by laurentiurad ↗ HN
I built ChipBuilder to make computer architecture more approachable through interactive puzzles.

You start with basic logic gates like AND, OR, and NOT, then gradually combine them into adders, multiplexers, memory, an ALU, and eventually a complete CPU. Once you've built the hardware, you can write assembly programs that run on the processor you created.

The game is inspired by courses like Nand2Tetris, but everything runs directly in the browser with a visual circuit editor, simulations, and progressively harder challenges.

47 comments

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I like it, it's fun Why you decided to keep wire button on top ? can't we do something like clicking on the dot will trigger wireing
you maybe not select accidental but others do:

user-select: none;

I wasn't able to wire the inputs to the gate, so my career at ChipCorp ended at level 1.

Also it would ne nice to have a level zero where you create the gates from transistors.

Got stuck at the NAND gate level.
Would be nice to be able to skip the first levels, because learning an AND gate is not necessarily what everyone needs as first steps, regarding their skill level.
wasn't there recently another game that was starting with mosfet/pmos?
This is cool! I like it! Let's see if I can get past the NAND level!
I wonder how people go through building such a project without ever hearing about NANDGame or Turing Complete.
Or Silicon Zeroes, or MHRD, or a bunch of other games that do the same thing.
Doesn’t handle drag and drop on iPad.
Very nice. Tips: You don't need the different design states (select, wire, delete) just have one and make it work contextually. Also remove the play button. Just have it always playing.
Since I don't see it mentioned here, Turning Complete is also a game along the same lines and really fun. https://store.steampowered.com/app/1444480/Turing_Complete/

I have gotten my nephew into it with some success as well.

Turing Complete was super fun and is amazing. It felt like a years worth of computer engineering class packed into a week’s worth of well designed gameplay. IIRC someone built a working 32 bit RISC-V CPU with it. (Maybe this one? https://github.com/BenjaminSchaaf/turning-complete-riscv)

My child just informed me that Turing Complete has just released a major redesign and that the engine is even faster than before.

Cool idea, but having to switch between select and wire makes this incredibly tedious to use. Just use wire mode from dragging from a connection and let people draw "away" a wire from a connection and let go to delete it? Would be much more intuitive imo.
To the author of this; Are you able to make it save your progress so you can come back and continue playing?
I went through Turing Complete up to a working CPU and found it incredibly fun. I then went on to build my own RV32I (simplest RISC-V instruction set) core in Verilog - if you keep a simple single-cycle design, it doesn’t end up being super complicated and not a ton of code. I’d recommend the exercise for anyone wanting to learn about how CPUs work.

Also, for people interested in this type of thing, look up Ben Eater’s 6502 videos. Wiring up a 6502 (old microprocessor) to ROM and RAM on a breadboard; later he builds a “world’s worst video card” - more like a VGA display output card, still pretty cool.

+1 for Turing Complete, it's absolutely marvelous.
My 14 year old son went further in the Turing Complete, where the game shows you how to "invent" Assembly language, and he completed couple challenges after that (like writing Assembly program to make a robot controlled by the computer you built in the game solve a randomly generated maze).

FYI the author started publishing updates again; looks like he took 2 years to rebuild the game from the ground up and instead of launching it as "Turing Complete 2" he chose to simply publish it as breaking update, and is now continuing with updates to add features.

That's a cool idea for a game, but the UX feels quite unintuitive and unpolished to me which discouraged me from playing past the first couple of levels. A few suggestions, if I may:

- You should be able to drag/drop elements from the sidebar onto the canvas

- Wiring shouldn't be a separate tool, and you should be able to drag/drop wires instead of having to click on the two endpoints separately

- You should be able to delete the currently selected gate with the delete key, and the "delete" button in the toolbar should delete the currently selected gate instead of it being a separate tool

- There's not enough contrast between the grid pattern and the background of the canvas

- There seems to be some problems with moving overlapping components

- There's no way to move around the canvas

- The progress doesn't seem to save and there's no way to skip levels

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pretty interesting that such lazy slop vibecoded into existence by "a software engineer passionate about well-crafted products."
"well-crafted" does not imply anything about the feature set or the ease of use.
Thanks a lot for your time in providing the feedback! I think every point is valid so will try to implement them.
To add to this.

- allow drawing wires backwards from sink to source

- allow connecting inputs

Also there is a problem with the tests and the simulator that showed up in the SR latch level. Despite having the correct circuit, the tests failed until I swapped the two NOR gates. I can not reproduce it, but I would guess it has something to do with the component placement order, the update order of the simulator, and how the tests are executed. As the NOR feedback loop has no well-defined initial state, it probably settled in a placement order dependent way that made the tests fail. Maybe Q was already 1 and the test looks for a 0 to 1 transition when enabling S?

Slop. very janky UI
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Forgive me if I'm wrong, but I just can't look at "AI aesthetics" anymore.
Thanks for the feedback! I am curious what made you think it's AI? My experience with using LLMs is that they usually use dark mode + neon + gradient a lot, but nothing like the design you see on my website. I'd highly appreciate if you share what elements you thought as being vibecoded or made with AI.
I like this idea a lot! I think that there are a few small details that would improve the user experience if you're looking for feedback.

1. Please please please apply `user-select: none;` to everything within the circuit canvas. Almost more often than not I would end up dragging text that had been highlighted rather than any of the actual gates or inputs.

2. Having to switch between 'select', 'wire', and 'delete' modes is a bit cumbersome.

3. Absolutely no progress seems to be saved on navigation or page reload. I've completed the first level several times and if I go anywhere else or reload after completing it, the site shows zero levels completed and shows the tutorial again.

3 next clicks in missing a back button
> You start with basic logic gates like AND, OR, and NOT, then gradually combine them into adders, multiplexers, memory, an ALU, and eventually a complete CPU. Once you've built the hardware, you can write assembly programs that run on the processor you created.

No you don’t. Once you get to memory you no longer have any tests that do anything and it’s impossible to actually progress.

Wow, sounds identical to "Turing Complete".
Really cool. I'm enjoying this.

One bit of feedback: I'd love to be able to stare at the tests while I'm playing around with the logic gates; every time I switch to the tests tab then click around on the "board," the tabs switch back.