How the Trackers Work

You don’t need to understand any of this to use the trackers. But if you’re the kind of person who likes to know what’s going on, this page is for you.

The short version

Each IBIS tracker is a tiny circuit board with a motion sensor (IMU) and a radio. The IMU measures how the tracker is rotating in space, many times per second. The radio sends that data over 2.4 GHz wireless to a USB receiver dongle plugged into your PC.

The SlimeVR Server running on your PC takes orientation data from every tracker, combines it with your body proportions, figures out where each of your limbs is, and feeds that into SteamVR (or VRChat OSC) as virtual full-body trackers.

That’s the whole stack:

[IBIS tracker IMU] → [2.4GHz radio] → [USB receiver] → [SlimeVR Server] → [SteamVR / OSC] → [game]

Why “nRF”?

IBIS trackers use a Nordic nRF52833 microcontroller with a built-in 2.4 GHz radio (the same family of chip you’ll find in many Bluetooth devices, but here it runs the SlimeVR “Smol Slime” firmware with a custom low-latency protocol). That’s the “nRF” in nRF-based SlimeVR designs.

IBIS trackers do not join Wi-Fi. They run on a dedicated 2.4 GHz radio link to the receiver, which means 30–70 hour battery life (50+ is typical), low latency, and no router configuration. The trade-off is range: nRF trackers transmit at much lower power than Wi-Fi trackers, so the receiver only covers your playspace (roughly 10 m), not your whole house.

What the trackers do not do

A tracker only measures rotation, not absolute position. SlimeVR figures out position by chaining rotations together using your body proportions (your hip is below the headset, the upper leg pivots from there, the lower leg pivots from the knee, and so on). This is why mounting calibration and body proportions matter so much — get those right and tracking is rock solid.

This is also why drift happens over time: small rotation errors accumulate. That’s what reset bindings are for — they tell the server “this is my new neutral pose, recalibrate.”

What the receiver does

The receiver is a small USB device with its own nRF52 radio (the VYRO VR Receiver uses an nRF52840). It listens for traffic from every paired tracker and forwards the packets to the SlimeVR Server over USB. There’s nothing for you to configure on it day to day; it’s plug-and-play. VYRO VR has shipped three receiver designs (HolyIOT, Styria, and the amplified VYRO VR Receiver) — they all work the same way, see Installing the Receiver.

Always use the extension cable

The extension cable is not optional. The receiver’s USB connector is small and fragile, and plugging it straight into your PC repeatedly can damage it. The cable also protects wireless range — 2.4 GHz is easily attenuated by your PC chassis. Extending the receiver up and out of the case can double or triple your effective range.

Where SlimeVR comes in

We didn’t invent the protocol. IBIS trackers are SlimeVR-compatible, meaning they run the SlimeVR nRF tracker firmware and work with the official SlimeVR Server software maintained by the SlimeVR project. Both are open-source. For deep-dive technical material (IMU calibration internals, sensor fusion math, AutoBone, the nRF firmware itself), the SlimeVR docs and their Smol Slimes section are the canonical reference.

Our docs cover the parts that matter for getting your IBIS trackers up and running. Anything below that layer, we’ll happily link out.