Lab
Hardware·
What is inside the SR116 / JY-Y3 ring: HR3918 sensor, Dialog radio, battery, charger, LEDs, and the 4-tap gesture.
In 10 seconds
HR3918 optical sensor (HR · SpO₂ · skin temp), a microphone and flash for memos, a Dialog DA14xxx BLE radio, a vibration motor, no screen. Two finishes, one firmware (V152). Sensor window on the palm side; four quick taps start a memo; the cradle produces fake vitals. Battery runtime is still unmeasured.
The box says · we measured — sensor, storage, battery, radio, firmware
| box | measured | |
|---|---|---|
| sensor | HR3918 | PPG, green + red LEDs and a photodiode in one window inside the band — HR, SpO₂, skin temperature |
| storage | 128 KB ROM + 96 KB RAM | that is the MCU; memos live in a separate flash — one 6-minute memo came off as ≈ 730 KB of Opus |
| battery | polymer, capacity not stated | runtime not measured. Level via cmd 6 — the BLE Battery Service reads 100 % regardless |
| charging | magnetic cradle | charging = 1 in cmd 6; the ring keeps sensing in the cradle (HR 80–103, 31 °C — the cradle, not you) |
| compatibility | Android 5+, iOS 10+, LoraFit | any BLE central — no pairing, no key |
| radio | — | Dialog / Renesas DA14xxx (SUOTA FEF5), MTU 512, advertises HID 0x1812 + vendor id 0x594A |
| firmware · names | V152 | 0x0098; SR116-088D / JY-Y3-011A = model + last 4 hex of the MAC, per unit |
Gestures and feedback·
| you do | the ring | on the wire |
|---|---|---|
| tap 4× quickly | vibrates once, starts a voice memo to flash | state 0x10 in cmd 0x2F; file count +1 when done |
| tap 4× again | vibrates, stops | 0x3D count; 0x36 <n> after a pull |
| single press (button) | — | cmd 40 event 01; release 02 → 00 |
ring-cli find |
vibrates | cmd 4 echo 01 |
| set on the cradle | charging | cmd 6 charging = 1, pushed every ~30 s |
The optical window lights during a measurement (green for HR, red/IR for SpO₂) — the only visible indicator. Wear it
with the window on the palm side, snug; no ticks in 30 s of ring-cli hr means the sensor does not see skin.
Not there: screen, speaker · time zones (Time) · authentication — anyone in range can do everything on this site (Security) · an FCC filing for the "2BSR6-SR116" id some listings quote (the chip came from the GATT table).
