It’s always nice to simulate a project before soldering a board together. Tools like QUCS run locally and work quite well for analog circuits, but can fall short with programmable logic. Tools like Wokwi handle the programmable side quite well but may have license issues or require the cloud. The Velxio project by [David Montero Crespo] is quite an excellent example of an (online) circuit simulator with programmable logic and local execution!
It’s built largely around Wowki’s AVR8JS library for Arduino simulation. All CPU simulation occurs on the local computer, while sketch compilation happens on the backend using official Arduino tools. But this was certainly not the most impressive aspect of the project. Likewise, Velxio features RP2040 execution using the rp2040js library. It also features the execution of some ESP32 derivative boards built around the RISC-V architecture using the RiscVCore.ts library.
For more complex CPU architectures like the vanilla ESP32, Velexio implements a QEMU simulation on the backend. This methodology even enables the execution of Raspberry Pi Python code. Multiple boards can also be used in the same simulation, allowing one to test interactions between Raspberry Pis and other boards! It can also expand to handle multi-file code executions and it keeps everything in a backend database. Of course, everything is wrapped together in a neat modern UI, with a circuit diagram, parts selector, and full-blown IDE. You can try it at velxio.dev. Or, you could execute it on your home lab; it’s just one docker compose away!
If you enjoy embedded simulations, make sure to check out this ember simulation on an RP2040. Not to mention other Arduino/browser simulators we’ve seen in the past.
