Description

The KY-039 Heartbeat Detector uses 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. 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 mostly based 50HZ or 60HZ fluctuate, so faint heartbeat will add considerable noise.

Required Hardware Devices

• Arduino controller × 1
• USB data cable × 1
• KY-039 Heartbeat Detector

Connecting

• Sensor pin S connect to Arduino pin Analoog 0 / A0
• Sensor pin + (middle pin) connect to Arduino pin 5+
• Sensor pin – connect to Arduino pin GND

Code

// Pulse Monitor Test Scriptint sensorPin =0;double alpha =0.75;int period =100;double change =0.0;double minval =0.0;void setup (){ Serial.begin(9600);}void loop (){staticdouble oldValue =0;staticdouble oldChange =0;int rawValue = analogRead (sensorPin);double value = alpha * oldValue +(1- alpha)* rawValue;   Serial.print(rawValue); Serial.print(","); Serial.println(value); oldValue = value;   delay (period);}