Like SimulIDE, but a browser course from transistors to a CPU
SimulIDE is a free, open-source (AGPLv3) real-time electronic circuit simulator for hobbyists and students, covering analog and digital components and microcontrollers such as PIC, AVR and Arduino, with a built-in code editor and debugger. It is a free desktop download (donations welcome): SimulIDE 1 is the most stable version and now only gets bug fixes, and SimulIDE 2 is the latest, still in development but stable enough for daily use. If that is what brought you here, digiwleea is a free, in-browser alternative with a different angle: you build a computer from the transistor up.
What SimulIDE is good at
SimulIDE is simple and real-time: you wire up components and watch the circuit run as you change it, with an oscilloscope, a logic analyzer and a serial monitor built in. Its real strength is microcontrollers: its editor and debugger (breakpoints, watched registers and variables) run Arduino, PIC or AVR code against the simulated circuit. (digiwleea is an independent project, not affiliated with SimulIDE.)
How digiwleea is different
digiwleea does not simulate microcontrollers; it shows what is inside one. You build gates from CMOS transistors in the browser with nothing to install, then compose adders, latches, registers, RAM and control logic into a working 8-bit CPU that you program in its own small assembly language, following a guided 40+ level course with theory lessons and an AI tutor (Wleea). SimulIDE is the better pick for testing microcontroller firmware and mixed analog circuits; digiwleea is the better pick for understanding how a processor works from the transistor up.
| SimulIDE | digiwleea | |
|---|---|---|
| Focus | Analog, digital and microcontrollers | Digital logic, transistor to CPU |
| Runs as | A desktop app you download | A web app, nothing to install |
| Microcontroller code | Editor and debugger: Arduino, PIC, AVR | No (you build the CPU instead) |
| Guided course to a CPU | No (a simulator) | Yes, 40+ levels |
| Price / license | Free, open source (AGPLv3) | Free lab and Act I; Premium for the full course |
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
Is digiwleea a good SimulIDE alternative?
Yes, if you want to understand digital logic from the ground up. digiwleea is a free, in-browser simulator with a guided 40+ level course where you build every gate from CMOS transistors and work up to a real 8-bit CPU, with an AI tutor to help.
Is digiwleea free?
The sandbox lab and the first act of the course are free and need no sign-up. An optional account adds the AI tutor and cross-device sync; the full course and expanded AI tutoring are included in the monthly or annual Premium subscription.
Do I need to install anything?
No. digiwleea runs entirely in your browser, on desktop or mobile, and works offline once loaded.