A cloud-free Home Assistant integration for cheap Lefun-protocol BLE smart rings — plus the room-presence lighting system built on top of it.
This started as "can I talk to this $10 ring without the ad-ware vendor app?" and turned into a whole-home, identity-aware follow-me lighting system. Everything runs locally — no cloud, no vendor app, no phone required.
Ti-Vision Smart Fitness Ring — ~$9.99, listed as "titanium" (it is, in fact, cheerfully plastic), pairs with the Lefun Health / Life app. Advertised as "Health Monitoring with Sleep Tracking, Blood Pressure, Heart Rate." Spoiler: sleep tracking needs an accelerometer, and there isn't one — but heart rate, SpO₂ and a blood-pressure estimate are all real, and that's plenty to build presence lighting on.
| Component | What it does |
|---|---|
lefun_ring.py |
Standalone Python CLI + library for the ring's native BLE GATT protocol (HR / SpO₂ / BP / battery / device info). Zero HA required. |
custom_components/lefun_ring/ |
Full Home Assistant integration — routes through HA's Bluetooth stack (local adapter or ESPHome BLE proxies), exposes sensors + services + real-time room tracking. |
ha-packages/lefun_ring.yaml |
The presence lighting engine: fused occupancy + follow-me automation + per-room toggles + helper scripts. |
dashboard/ |
Lovelace dashboards — the ring, and the BLE-proxy fleet. |
The vendor app advertises steps, sleep, and "shake for camera/find-phone" gestures.
None of them work — because this ring has no functional accelerometer. After exhaustive
testing (steps stuck at 0 through every protocol path, zero shake events across minutes of
violent shaking with the camera gesture armed, and a find-phone opcode that streams on a
fixed timer regardless of motion), the verdict is clear:
Every optical feature works (heart rate, SpO₂, blood-pressure estimate). Every motion feature is dead. The firmware is generic Lefun code flashed onto hardware that only carries the PPG die — so it advertises the step/sleep/gesture opcodes but has nothing to feed them.
That single fact reshaped the project: with no shake-button to catch, there was no reason to hold a persistent BLE connection — so the ring is left free to advertise, which is exactly what makes room tracking possible.
The room you walk into turns its lights on; the room you leave turns off.
Occupancy for each room is fused from up to three independent estimators, whichever fires first:
ring advert ─▶ nearest-proxy tracker (custom, recency-weighted) ┐
ring advert ─▶ Bermuda BLE trilateration ├─▶ room occupancy ─▶ that HA
mmWave ─▶ ESPHome radar presence (instant, identity-blind) ┘ (OR-fused) area's
button_lights
- BLE (ring): knows who (identity), covers every room, but is slow — a cheap ring advertises sparsely (~once/minute when idle) and can't wake on motion. Two independent BLE estimators (a custom nearest-proxy tracker and Bermuda) run in parallel; first to resolve the room wins.
- mmWave radar (optional): instant and holds while you sit still, but identity-blind. Plug one into a room and that room upgrades to sub-second response automatically — no config change. (The reference deployment currently runs on the ring's adverts alone; the radar inputs are wired and waiting.)
- Self-healing: each room manages itself (no cross-room reconcile), lights fire only on the occupancy rising edge, so a manually-darkened room stays dark, and a room left lit by a missed transition is cleaned up on the next event. Optional "only when dark" gate.
The result degrades gracefully at every layer: radar down → BLE carries it; one BLE tracker glitches → the other covers; ring out of range → the room simply clears.
Hardware requirement: room tracking needs Bluetooth proxies
— one per room you want tracked. This is well-trodden Home Assistant territory: any ESPHome
node with bluetooth_proxy: enabled works, and the proxies can do double duty (this house
runs a fleet of ESP32-C3 devkits that simultaneously proxy adverts, hold iTag button
connections, and bridge BLE battery monitors).
- SoC: Nordic nRF-class — exposes the genuine Nordic Secure DFU service
0xFE59. Likely a PhyPlus nRF-clone, the family Gadgetbridge's Lefun driver targets. - Data protocol: Gadgetbridge Lefun — service
0x18D0, write0x2D01, notify0x2D00, request preamble0xAB, response0x5A, bit-wise CRC8, big-endian payloads. - Optical (works): heart rate, SpO₂, single-value blood-pressure estimate (PPG
0x0F→0x10). - Motion (dead): steps
0x12/0x13, sleep0x15, shake gestures0x0A/0x0E— no IMU. - Quirks: DIS strings gated (
NotPermitted— get identity via cmd0x00); power-saves hard; a connected ring stops advertising (the tracking-vs-connection tradeoff).
python3 -m venv .venv
.venv/bin/pip install -r requirements.txt
# one-time bond
bluetoothctl --timeout 15 scan on
bluetoothctl pair <RING_MAC> && bluetoothctl trust <RING_MAC>
# read live data
.venv/bin/python lefun_ring.py --address <RING_MAC> hr
.venv/bin/python lefun_ring.py --address <RING_MAC> poll
Or manually: HACS → ⋮ → Custom repositories → add https://github.com/jphein/smartring
(type: Integration) → install Lefun Smart Ring → restart HA.
- Copy
custom_components/lefun_ring/into your HAconfig/custom_components/. - Restart HA → Settings → Devices & Services → Add Integration → "Lefun Ring" (auto-discovers via any Bluetooth adapter or ESPHome proxy).
- For follow-me lighting: drop
ha-packages/lefun_ring.yamlin yourpackages/, label the lights in each room with thebutton_lightslabel, and toggle rooms on from the dashboard. - Import a dashboard from
dashboard/(storage-mode Lovelace YAML).
See custom_components/lefun_ring/README.md for
integration details.
- Protocol ported from the Gadgetbridge Lefun driver. Room trilateration by Bermuda.
- Because the protocol code derives from Gadgetbridge (AGPL-3.0), this project is licensed AGPL-3.0.
Not affiliated with Lefun. "Lefun" is used only to identify the protocol these rings speak.