10.3 Pulse Monitor

Hardware Wiring

Pulse Monitor

Sketch

The code can be found at Examples_Arduino - sensor-kit-for-arduino - _035_PulseMonitor - _035_PulseMonitor.ino.

int ledPin=13;
int sensorPin=0;

double alpha=0.75;
int period=20;
double change=0.0;

void setup()
{
  pinMode(ledPin,OUTPUT);
}

void loop()
{
  static double oldValue=0;
  static double oldChange=0;
  int rawValue=analogRead(sensorPin);
  double value=alpha*oldValue+(1-alpha)*rawValue;
  change=value-oldValue;

  digitalWrite(ledPin,(change<0.0&&oldChange>0.0));

  oldValue=value;
  oldChange=change;
  delay(period);
}