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Comment by dmonterocrespo | Hacker News Reader

Velxio 2.0 is live.

A free, open-source emulator for 19 embedded boards: Arduino, ESP32, Raspberry Pi, RISC-V , running real compiled code in your browser.

The best part: it's fully local.

No cloud dependency. No student accounts. No data leaving your network. Self-hostable with a single Docker container.

Universities and bootcamps can deploy it on their own servers and give every student access to a complete embedded development environment, for free.

I've been working on this for over a year, and just shipped v2.0 with ESP32 emulation (via QEMU), a custom RISC-V core, and Raspberry Pi 3 support that runs real Python

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Emulating the CPU is nice, but the trouble has always been emulating the peripherals

Does your editor do this? I tried the example but didn't see e.g. LEDs blinking

You can add peripherals There’s a “+” button on the right side of the circuit editor where you can add components like LEDs

Yes,peripherals are fully emulated, not just the CPU. LEDs blink, buttons respond to clicks, Serial Monitor works, servos rotate, displays render (ILI9341 TFT), and we have 48 o more components from the wokwi-elements library. The Blink example should show the built-in LED toggling on pin 13. If it didn't blink for you, it might be a compilation issue

try the example Traffic Light : Simulate a traffic light with red, yellow, and green LEDs

does this handle the timing differences between browser execution and real time hardware? or is it focused on logic verification?

Both, with a nuance. The AVR simulator syncs to wall-clock time and each frame calculates cycles from real elapsed deltaMs, so delay(1000) takes 1 real second and timer-dependent code (PWM, millis()) runs at correct real time rates. The RP2040 and ESP32-C3 simulators use a fixed cycles-per-frame budget (125MHz/60 and 160MHz/60 respectively), which targets real time but doesn't compensate for frame drops . if the browser stutters, emulated time stretches slightly. All three are cycle-accurate at the instruction level though, so the logic and peripheral behavior is faithful to real hardware regardless of frame timing

just curious - if it runs from a docker container, what is the advantage of running the browser as opposed to just ssh'ing in ?

The main advantage is accessibility and ease of use: with the browser, no setup is required on the user’s side, no toolchains need to be installed, and there’s no need to be familiar with SSH or terminal workflows

It also provides a more visual and interactive environment (editor, peripherals, simulation controls), which is especially useful for teaching and for beginners.

The Docker image is there so you can easily install it on your own machine if you want to run it locally or work on development

The visual component editor does look pretty nice :-) I guess I always just associated sbc's with a more 'hands on' style...

Anyway, seems like a pretty cool project - congrats!

Thanks! The visual editor is actually a big part of the project

I used a little AI to create the graphical interface since I focused heavily on emulation, testing, and refining and optimizing the circuit editor. But now I have plans to improve the UI and make it faster and more intuitive

Still a lot to improve there, but glad it’s useful already

Is it easy to feed an elf or bin and run that (esp32c3)? I see compilation available, but I'm playing with asm and have my toolchain figured out already and would just like to emulate the firmware.

Another +1 for this one as this is what turns this tool from a toy environment with basic sketches into something that's actually useful for larger projects with a full toolchain, libraries, and so forth.

That’s exactly the direction I’m aiming for

A lot of simulators stop at simple sketches, but the goal with Velxio is to support more realistic workflows , multiple boards interacting, real toolchains, and more complex setups

Still early, but definitely moving in that direction

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