Show HN: BBRouter – Ben Eater's 8-bit computer, simulated on 3D breadboards (bbrouter.com)

53 points by creack •

Hi HN,

I kept wiring Ben Eater's 8-bit computer wrong, so I built a realistic virtual breadboard editor.

Some of the nice features are side-by-side diff, scope, schematics auto-sync, auto-router (BBRouter stands for breadboard router), and my favorites: upload from the real Arduino IDE and connect to your AI with MCP, let Claude & co build it or help you troubleshoot.

The link is the SAP-1 running. You can orbit it, probe a hole with the scope, slow the clock down, play with the virtual displays for debugging, then you can actually build it following the step-by-step instructions.

A side-goal is to create a community, there are quite a lot of simulators out there but mostly offline / too abstract to realistically use it for a real build. I also never found one that had a decent UI/UX and worked well on mobile or with a trackpad.

Happy to answer anything, and tell me what breaks.

p.s. Maker plan is $7/month; code HACKERNEWS makes the first month free and then $5/month for as long as you keep it.

How can I hide or move the ram program window? It's blocking the breadboard.

Sorry about that, last minute bug, pushing a fix now to hide it on small screens.

In the meantime you can tap the layer icon on the bottom left and disable “displays”. In a few minutes, I’ll have the fix deployed to avoid blocking the screen

Fix deployed.

This looks amazing. Congratulations on the launch.

I was hoping to find Ben's Digital breadboard clock [1] in there, I'm currently building it!

[1]: https://eater.net/clock

Thank you! Unfortunately, not yet supported but soon! it's the next example I want to add: the 74HC counters are already in, what's missing is the 60 Hz mains-derived time base.

Congrats on the launch. Have fond memories of early 2k where everything starting with bb was amazing

Hehe, indeed, thank you. It stands for breadboard here, but I had to include a bulletin board too ;)

This is cool, but seriously I don't understand why you wouldn't just use Verilog (or VHDL) along with the wide number of associated tools available for it. It's trivially simple to create modules for TTL chips. Also you could design the schematic in KiCad and then export the netlist to Verilog for simulation. Verilog has VPI- a method to connect the simulation to external programs (C/C++), from which you could make a GUI for LEDs and switches. Once your design is in Verilog, you could compile it into C++ [Verilator], an FPGA or even an ASIC.

It's like choosing to use LabView for a large programming project (or IMHO, even a small project) instead of something like Python.

As I often prototype on breadboard, I wanted to tool that could realistically model what I work on, especially when it comes to wire size, length, bends, etc.

I used KiCad a lot and I took direct inspiration from it for the schematics view, and when designing a PCB it is great, but when it comes to play with breadboards, there is a void.

The goal is to experiment and mirror reality, but I would agree that if you want to do a serious project that is not just a one-off, BBRouter is probably not the tool for you. If you want to have fun, follow along tutorials like Ben Eater's, experiment various changes in branches without spending money, time and frustration on components/wires, then it fits quite well :)

Incidentally I was just thinking about Ben Eater's breadboard setup when I rebuilt a super simple audio circuit (ESP32, MAX98357 ....) from breadboard to a soldered contraption because there was so much noise due to the connectors. Do digital circuits on breadboards not have this problem?

The current simulation is mostly only digital, I am working on a more accurate analog one that may be able to reproduce this. ESP32 is also slightly more difficult to simulate, I currently have only Arduino (Nano, Uno, Mega), but ESP32/8266 are on the roadmap.

In the past, I had quite some luck working around real breadboard noise by adding decoupling capacitors and makeing sure everything has a pull-up/pull-down resitor so when you look at the board it doesn't randomly jump state.

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