I heart Processing

Investigating hooking up a heartbeat monitor to Processing

Ingredients

• A heart rate sensor – I used this PulseSensor one
• An Arduino – I used a Diecimilia
• A laptop running a Processing sketch that listen to the USB port (where I’ve plugged in my Arduino) and sucks in any data that arrives (see the helpful sparkfun tutorial).

Method

1. Connect your PulseSensor to the Arduino. The physical set up looks like this (using the helpful PulseSensor getting started guide):
   
2. Connect your Arduino to your computer. Run some listening code in Processing on your computer – download the code and paste it into a sketch. Essentially, we use the serial package to set up a Serial object, which triggers serial events every time there’s enough data for us to do something with. The data coming from the PulseSensor is a bit of text (a String) which either stars with an S, B or Q followed by a number, so here’s how we grab that number out of it:

   /* a special function which captures "serial events" - i.e. data sent from the serial port */
   void serialEvent(Serial port)
   { 
      String inData = port.readStringUntil('\n');
      inData = trim(inData);   // cut off white space 
      
      println(inData); // debug! see what you've got
      
      if (inData.charAt(0) == 'S') //leading "S" for sensor data
      {          
        inData = inData.substring(1); // cut off the leading 'S' 
        Sensor = int(inData);         // convert the string to usable int
      }
      if (inData.charAt(0) == 'B') // leading "B" for BPM data
      {          
        inData = inData.substring(1); // cut off the leading 'B'
        BPM = int(inData);            // convert the string to usable int
        // set beat flag to advance heart rate graph
        beat = true;
      }
    if (inData.charAt(0) == 'Q') // leading "Q" for IBI data
    {            
        inData = inData.substring(1); // cut off the leading 'Q'
        IBI = int(inData);            // convert the string to usable int
    }
   }

• Look at the code’s

  keyPressed()

  method – you can switch between the two modes defined in

  draw()

  by pressing either 1 or 2!

• Screenshots from the code (not very exciting so please do experiment with your own patterns!

Examples of doing things with heart rates:

• Visualising heart rate
• Mapping heart rate against a Game of Thrones episode: