Digital UV Index Sensors Track Sun Exposure, Biometrics

A new facet in activity tracking for smartphones and wearable computing devices comes by way of Silicon Labs with its digital ultraviolet (UV) index sensor ICs. The single-chip Si1132 and Si114x sensors are designed to track UV sun exposure, heart/pulse rate, and blood oximetry, as well as provide proximity/gesture control for wrist and arm bands, smart watches, and smartphone handsets. They also provide ambient light and infrared (IR) proximity sensing capabilities, as well as UV index sensing, for health and fitness applications. The Si1132 uses a standard I2C interface to read digital UV index values, while the Si1145/46/37 offer a choice of one, two, or three integrated LED drivers with 15 selectable drive levels for gesture detection. Those LED drivers also enable implementation of reflective heart-rate and blood-oximetry measurement capabilities. When combining any of the sensors with an accelerometer, developers can implement sleep tracking in wearable applications. The 2- by 2-mm sensors’ ultra-low-power architecture allows for thinner wearable designs with smaller batteries, and extends battery life using as little as 1.2-µA average current for once-per-second UV measurements.

SILICON LABS