I built specifically:<p>The browser-based IDE (editor, project handling, UI)<p>The circuit simulation layer that connects components to the emulator<p>The glue between the AVR8 emulator and the virtual peripherals (GPIO, UART, SPI, etc.)<p>The component interaction system (buttons, LEDs, displays, etc.)<p>The architecture that lets compiled Arduino sketches run and interact with the simulated hardware<p>Some parts like the AVR CPU emulation and the compiler toolchain obviously come from existing projects, but the goal of Velxio wasn't to re-implement an AVR core from scratch. It was to build a usable environment where all of these pieces work together in the browser.<p>I'm still having trouble connecting the cables and components properly. I'm looking for a better algorithm. I'm also trying to create a real-world electronics simulator in JavaScript using an engine like CircuitJS1.