Everlight introduces ambient light sensor for wearables
LED and optoelectronics firm Everlight has introduced the 550nm ALS-PD50-42C ambient light sensor for heart rate signal detection in wearable electronics for the health and fitness industry.
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.
With a larger than usual detection area of 8.1mm2, the device is said to improve the capabilities in instances when there are signal interferences caused by people's skin color, tattoos and hair on the skin. This feature allows for accurate and reliable detection for the wearable heart rate technology. Ideally, this technology is a benefit for runners who rely on accurate wearable devices.
Everlight's ALS-PD50-42C series is said to feature a very efficient current transmission. A current signal output of 0.8µA 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 ALS can be operated within a supply voltage range from 0 to 5V in a temperature range from -25degC up to +85degC. This device is rated to be RoHS compliant, Pb-free and halogen-free.
