KY-039 Finger Heartbeat Detection Sensor

KY-039 Finger Heartbeat Detection Sensor
The KY-039 Finger Heartbeat Detection Sensor is a sensor that can detect a person’s pulse or heartbeat. It is a small, portable sensor that easily connects to an Arduino or other microcontroller to read and analyse heart rate. The sensor is made up of a finger clip that attaches to the finger and an infrared sensor that detects blood flow through the finger. The sensor sends information to the microcontroller, which computes the heart rate. The sensor generates an analogue output signal that the microcontroller can read.
The LED is on the light side of the finger, and the phototransistor is on the other side of the finger, the phototransistor is used to obtain the flux emitted when the blood pressure pulse 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 a desirable phototransistor sensitive enough. 
The most important is to keep the shield stray light into the phototransistor. For home lighting that is particularly important because the lights at home are mostly based on 50HZ or 60HZ fluctuating, so a faint heartbeat will add considerable noise.
Applications:
DIY Heart Rate Sensor
Heart Rate Monitor Using IoT
MAX 30102 Heart Rate Monitor on 16×2 LCD
Package Includes:
1 x KY-03T Finger Detection Heartbeat Measuring Sensor Module
Specifications
Model 
KY-039
Sensor Type 
Finger Detection Heartbeat Measuring Sensor
Dimensions 
2  x 1.4cms 
Weight 
5 grams