For basic prototyping, the go-to tool to piece together a functioning circuit is the breadboard. It’s a great way to prove a concept works before spending money and time on a PCB. For more complex tasks we can make use of simulation software such as SPICE. But there hasn’t really been a tool to blend these two concepts together. That’s what CRUMB is hoping to solve as a tool that allows simulating breadboard circuits.

Currently, most basic circuit functions are working for version 1.0. This includes passive components like resistors, capacitors, switches, some LEDs, and potentiometers, as well as some active components like transistors and diodes. There are some logic chips available such as 74XX series chips and 555 timers, which opens up a vast array of circuit building. There’s even an oscilloscope feature, plus audio output to incorporate buzzers into the circuit simulation. Currently in development is an LCD display module and improvements to the oscilloscope.

Besides prototyping, this could be useful for anyone, students included, who is learning about circuits without the need to purchase any hardware. The major downside to this project is that it there doesn’t seem to have a free or trial version, the source is not available, and it’s only for sale on Steam, Apple Store, and Google Play. That being said, there is a forum available for users to discuss problems and needs for future versions, so it’s possible that a community could build up around it. We’ve seen previously non-free versions of circuit simulation software become more open after some time, so it’s not out of the realm of possibility.

Thanks to [Thomas] for the tip!