KY 039 Heart Rate Heart Beat Detector Sensor Module

This KY-039 Finger Detection Heartbeat Measuring Sensor Module uses bright infrared (IR) LED and a phototransistor to detect the pulse of the finger, a red LED flashes with each pulse.

The LED is on the light side of the finger, and the phototransistor is on the other side of the finger, phototransistor is used to obtain the flux emitted when the blood pressure is pulsed by the finger when the resistance of the phototransistor will be slightly changed.

We chose a very high resistance resistor R1 because most of the light through the finger is absorbed, it is desirable that the phototransistor is sensitive enough. Resistance can be selected by experiment to get the best results. The most important is to keep the shield of stray light in the phototransistor.