Hardware
The Wellex bracelet hardware spec for engineers.
Last updated: 2026-04-07
SoC
Custom low-power Cortex-M55 with a Helium ML extension. 256 KB SRAM, 1 MB flash. Runs the on-device feature extraction and the small ML kernel.
Sensors
See Bracelet: Sensors for the user-facing list. Engineering details:
| Sensor | Part | Sample rate |
|---|---|---|
| PPG green | OSRAM SFH 7050 | 100 Hz active, 25 Hz idle |
| PPG red+IR | OSRAM SFH 7072 | 25 Hz |
| IMU | Bosch BMI270 | 50 Hz |
| Skin temp | TI TMP117 | 1 Hz |
| GSR | Custom analog front-end | 4 Hz |
| Bioimpedance | Maxim MAX30009 | 1 Hz |
| Ambient light | Vishay VEML7700 | 1 Hz |
| Barometer | Bosch BMP384 | 1 Hz |
Battery
110 mAh Li-Po. Up to 14 days, ~10 days typical. USB-C magnetic dock charges in ~90 minutes.
Radio
BLE 5.3, no Wi-Fi, no cellular, no UWB.
Mechanicals
32 g, 7.4 mm thick, hand-woven outer. 5 ATM water resistance.
OTA updates
Firmware updates ship over BLE through the phone app. ~2 minutes typical update time. No reboot loop on failure — the band rolls back to the last known good build.