Everlight presents an ambient light sensor for wearable devices

Posted 24 February 2017

Everlight Electronics introduces the ALS-PD50-42C, an ambient light sensor for wearable devices. Suitable for applications like heart rate signal detection in wearable electronics for the health and fitness industry, this device operates at a 550nm and has a very low signal calculation failure rate and a high current efficiency.

Based on the principle of PPG (photoplethysmogram), the heart rate signal is calculated according to the current changes in transmission and reflection between the green light LED and the sensor to detect the systolic and diastolic blood vessels.

A current signal output of 0.8 μA at a light current of 100 Lux from a white LED (Vr = 5V) improves detection on capillaries resulting in overall accurate signal strength. The device’s coating design effectively reduces the interference from UV light below 400nm and infrared light above 650nm, thereby decreasing the effect of strong sunlight from outdoor exercise to ensure accurate measurements.

The new ambient light sensor has a detection area of 8.1mm2 and can be operated within a supply voltage range from 0 to 5V in a temperature range from -25°C up to +85°C.