Miro v2 FBT: Documentation & Resources
Everything that makes Miro tick.
Miro v2 trackers are compact nRF-based SlimeVR full-body trackers built on a custom PCB. This page collects the technical details, setup steps, build documentation, and download links in one place.
01. Technical Overview
What Miro v2 trackers are
Miro v2 is a build of the Smol Slime (nRF) family of SlimeVR trackers, housed in custom 3D-printed cases. Where earlier builds stacked an IMU module on top of an off-the-shelf dev board, Miro v2 moves to a custom PCB: the nRF52840, IMU and supporting circuitry are laid out on one purpose-built board.
The IMU is the STMicroelectronics LSM6DSV, a low-noise, low-power 6-axis sensor (3-axis accelerometer + 3-axis gyroscope). Like all nRF trackers, Miro v2 communicates over a heavily modified Enhanced ShockBurst (ESB) protocol via a receiver dongle, which relays motion data to the SlimeVR Server running on your PC. The trade-off pays off in power: the trackers draw very little current and run for days per charge.
02. Specifications
Hardware at a glance
Typical configuration for a Miro v2 build.
- Board
- Custom Miro v2 PCB
- MCU
- Nordic nRF52840 (nRF528x series)
- IMU
- STMicroelectronics LSM6DSV (6-axis)
- Battery
- 3.7V LiPo, 401230 size, JST-ACH connector
- Link protocol
- Modified Enhanced ShockBurst (ESB)
- Receiver
- USB dongle, included with every set
- Weight
- ≈9 g per tracker
- Battery life
- 24h+ use from ~1h charge
03. Setup Guide
Getting set up
Everything you need to go from a fresh box to tracking in-game is in the dedicated setup guide.
Miro Setup Guide
The complete walkthrough for a new Miro set, from unboxing to your first session.
Trackers ship flashed and ready. If you ever need to update them, SlimeNRF Serial Control flashes both the trackers and the receiver over USB, with no extra tools needed.
04. Build Your Own
Build it yourself
The Miro cases are open hardware, released under CC BY-NC-SA 4.0. If you'd rather build your own, the documentation and STL files are public.
The build-it-yourself route covers the stacked tracker design: an nRF52840 dev board with an IMU module stacked on top, wired by hand. Miro v2 trackers use the custom PCB described in the overview. The custom PCB is not part of the DIY build path.
Assembly Overview
The stacked build places an IMU module on top of a SuperMini nRF52840 board, wired together and fitted into the printed Miro case. The soldering tutorial walks through board prep, the reset button, DFU mode, IMU preparation and stacking, battery wiring, and final assembly into the case.
Recommended Print Settings
- Layer height 0.2 mm
- Infill 15–20%
- Supports Manual recommended
- Material PLA / PETG
- Tip Test-fit before a full set
License Miro case files are released under CC BY-NC-SA 4.0: share and adapt for non-commercial use, with attribution, under the same license.
05. Quick Release Hooks
Quick release hooks
Miro cases use a quick-release hook system so a tracker can be taken off its strap, and put back, without unthreading anything.
What they are
The hook is a single-piece printed part that connects a tracker to its strap. The strap loops through the hook and fastens back to its own other end, holding the hook on the strap; the hook then attaches to the tracker case, so the tracker comes off as a unit.
Two sizes are available: one for 25 mm straps
and one for 38 mm straps. STL files for both
(hook 25mm and hook 38mm) are in the
miro-cases repository. The design is based on the original
quick-release hooks by Kurzaq, adapted for Miro.
Why it's useful
A quick-release system means you can:
- Take trackers off for charging without disturbing strap fit.
- Store or pack the trackers flat, straps left as they are.
- Swap a worn strap without rebuilding the whole tracker.
- Move a tracker between body positions quickly.
- Choose the hook that matches your strap: 25 mm or 38 mm.
- Feed the strap through the hook, then fasten it back to the strap's other end so the hook sits on the strap.
- Attach the hook to the tracker case. To remove the tracker, unhook it; the strap stays in place.
06. Downloads & Links
Downloads & links
Source files, documentation, and community channels.
Miro Cases repository ↗
STL files, documentation, and the build tutorial. Released under CC BY-NC-SA 4.0.
GitHub · GuideSoldering tutorial ↗
Step-by-step build for the stacked tracker design: board prep, IMU stacking, battery wiring, and case assembly.
FilesSTL files ↗
Printable case parts, plus the 25 mm and 38 mm quick-release hooks.
GitHub · AppSlimeNRF Serial Control ↗
Free desktop app for configuring, calibrating, and flashing trackers over USB. Windows, Linux, and macOS.
DocsSlimeVR Documentation ↗
Official SlimeVR setup, calibration, and troubleshooting documentation.
DocsSmol Slime Documentation ↗
Hardware, firmware, pairing, and calibration docs specific to nRF trackers.
CommunityMiro Discord ↗
The Spiro Discord for Miro owners and builders: direct help, updates, and community chat.
CommunitySlimeVR Discord ↗
The wider SlimeVR community for setup help, troubleshooting, and general FBT discussion.
Need a hand?
Questions about your trackers?
Reach out in the Miro Discord for direct help, or in the wider SlimeVR Discord for general FBT troubleshooting. The community is the fastest route to setup and troubleshooting help.