Group 106-11

This is our custom built heart beat monitor. It uses a Infra-Red(IR) emitter and detector to detect heart beat. The concept is to detect a change in Infra Red detected by the IR detector with each pulse. You can see the two led at the left corner of the circuit board. The darker one is the emitter and the transparent one is the detector. Both placed in a foam to minimize the ambient infra red detection.
The electrical signal needs to be amplified so we are using Op-Amp 741 and then its output is filtered using three stage filters to minimize the noise. This signal is then fed into a single analog input in the Arduino.

The Arduino board is programmed to read the analog data and perform a serial output every 15ms. A Processing code is written on a PC to receive this data. The Prrocessing code contains a serial listener which get the data sent by the Arduino through the serial port. This data is then plotted on to the screen. For plotting a black screen is drawn and a line is made connecting adjacent data point as they come to give a running graph.