An LED of a wearable sensor device can be driven less frequently while still obtaining an accurate biometric sample. By reducing how frequently the LED is driven, the power required to operate the wearable sensor device is likewise reduced. To allow the LED to be driven less frequently while still obtaining an accurate biometric sample, a known lighting profile of an LED can be employed with a matched filter to generate a biometric sample from a number of samples taken while the LED is lighting. In this way, the LED only needs to be lighted for a short period of time and a reduced amount of data is stored both of which minimize the power requirements of the wearable sensor device.
