Microcontrollers
Full AVR simulation, plus ESP32 and Raspberry Pi Pico boards running real firmware, with more chips to come. Yes, it runs DOOM.
Circuit simulator for Windows, macOS and Linux
Coming soon
Build any circuit.
Make any part.
Share it all.
Analog into the megahertz, microcontrollers running real firmware, robots that move under real physics, guitar pedals you can play through, even a whole 8-bit computer: all simulated together, live. When your design works, flash the code to a real board.
Already own CRUMB? CRUMB Advanced is added to your Steam library free on launch day.
100,000+copies of CRUMB sold on Steam
3 platformsWindows, macOS and Linux
WorkshopCommunity parts on Steam
Free upgradefor every original CRUMB owner
Features
What can CRUMB do?
Everything on the breadboard is simulated, from the circuit solver up to the motors, screens and sound.
Instruments
Probe any node with the scope and multimeter while the circuit runs, and see a signal's spectrum with the FFT.
Physics
Motors, servos and joints are real bodies, moved by the current your circuit supplies.
Live audio
Play a guitar, a microphone or a WAV file through circuits you build, in real time: fuzz, gain, valve tone or anything you design.
Sensors and displays
Displays and sensors on SPI, I²C, UART, 1-Wire and more, with environment zones for temperature, humidity, light or any value you define.
Digital logic
Logic chips, EEPROMs and displays on breadboards: enough to build and run an 8-bit computer.
That's only what ships. Make any part you need, or get one from the Steam Workshop.
Learning campaign
Start with one LED. Finish with your own designs.
Ten tiers of guided challenges, from closing your first circuit to programming microcontrollers and building machines that sense and move. Every challenge is checked live, while the circuit runs.
- Tier 1First principlesClose the loop, light an LED and take your first reading
- Tier 2Ohm's lawBuild it and measure it: Ohm's law and DC networks
- Tier 3CapacitanceCapacitance, time and the oscilloscope
- Tier 4TransistorsDiodes, transistors and power
- Tier 5Op-ampsOp-amps and analog signal processing
- Tier 6Digital logicDigital logic, timing and displays
- Tier 7Fault findingFault finding, diagnosis and repair
- Tier 8MicrocontrollersMicrocontroller programming
- Tier 9MechatronicsMechatronics, sensing and control
- Tier 10CapstoneOpen design briefs and the capstone
Docs and component API
Build the parts you need
Every part in CRUMB is made with the same tools you get. Write its behaviour in the built-in editor, give it your own shaders, see each change live with hot reload, then share it on the Workshop.
Winding (circuit logic)Hot reload ●
public override void PreStep()
{
// Latch once per tick: back-EMF from the rotor speed.
double dt = Simulation.TimeStep;
double emf = Properties.Ke * UserData[0];
_geff = 1.0 / (Properties.R + Properties.L / dt);
_isrc = _geff * ((Properties.L / dt) * _iPrev - emf);
}
public override void Step()
{
int a = ConnectionNodes[Connections.Red];
int b = ConnectionNodes[Connections.Black];
Simulation.StampConductanceDynamic(a, b, _geff);
Simulation.StampCurrentSourceDynamic(a, b, _isrc);
}Roadmap and tracker
Built in the open
See what's being worked on, vote on the bugs and features that matter to you, and follow each one to the update that shipped it.
Roadmap
Full roadmap →Loading the roadmap…
Found a bug? Got an idea?
Sign in with the Steam account that owns CRUMB and post it on the tracker, where owners vote on what matters most. Only owners can post, which keeps it free of spam.
Bug reports open when CRUMB Advanced is released. Feature requests are open now.
Suggest a featureBug reports open when CRUMB Advanced is released
Every report shows its status
- New
- Confirmed
- In progress
- Fixed in 2.0.x
Original owners · Coming soon to Steam
Own CRUMB? Advanced is yours, free.
Everyone who owns the original CRUMB on launch day gets CRUMB Advanced added to their Steam library automatically. Pick up CRUMB now and you're covered.