Notes · Other Peoples' Talks · FOSDEM 2026 · SlimeVR Full Body Tracking
https://fosdem.org/2026/schedule/event/TBFSCP-slimevr/
- Take a bunch of small trackers with IMUs, put them on your body, connect them to a device, and then determine pose
- How it happened:
- "fuck around and find out"
- Wanted a way to track body in 2020, but lighthouse tracking is absurdly expensive
- Android app that could be run on your phone, and then putting your phone on your hip
- Limited, but can get more immersion because you can twist your hip and bend down
- Joined the Discord server and asked if it would be possible to combine an ESP32 + IMU to substitute for the phone
- Went ahead with it
- Ended up assembling a bunch more kits and hacking something together
- First version of the server using Java and Swing
- Very awful UX
- How it's going
- Open-source, so people started rebuilding it
- TypeScript / React / Tauri (Rust) / Kotlin / Proper UX
- Stack is low-key insane: 6 different languages (C, C++, Java, Kotlin, Rust, TypeScript)
- The server is still Java/Kotlin
- Java is being removed in the future
- Very open-source from the start: Apache 2/MIT
- Including the hardware
- Other people were able to produce the hardware before Slime could, which essentially acted as free bug-testing for them before doing mass-production
- People built their own variations with better IMUs and this fed back into the mass-production
- 186 contributors on GitHub
- Half of them are probably translators, but a lot of people contribute in general
- Very big DIY community
- If you have a microcontroller and an IMU, you can put something together yourself
- Be careful with lithium batteries...
- Can be found on website, Discord, Bluesky, YouTube
- Can buy from Crowd Supply; butterflies are at https://slimevr.dev/smol
- Question: Do you have a quickstart guide?
- Yes, for both DIY + official
- Question: What is the hardware?
- Previous generation: Espressif chips over Wi-Fi. Built on Arduino framework, but using PlatformIO.
- Question: Can it be used with VRChat?
- Main user; what it was literally built for.
- Demo was for more experimental mocap.
- Question: Why not copyleft?
- Really hate GPL + copyleft
- Didn't want to take contributions at gunpoint
- Wanted it to be simple and easy, and encourage a community spirit of contributing back
- Lots of the maintainers think similarly
- Question: Mobile support for motion capture?
- Can actually already do that; server already runs on Android. iOS is planned, but very complicated
- Can also run on Raspberry Pi and on standalone headsets
- Server also supports recording BVH motion capture, but still experimental
- If more people use it, there will be more development