My Circuit Design

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I am using Proteus 7.7b to design and simulate the circuit diagram for my fyp project. This is the analog part of my circuit. How it works?

1. The circuit is supplied with 5 volt power supply.
2.  IR led and Green led will turn on because current will go through C1 due that ldr is made of high resistance semiconductor.
3. Put fingertips near the optical sensor, it will cause the Green Led to blink indicating our rate of heart beat.

Theories and explanation?

Heart rate is measured by sensing the change in blood volume in a finger artery  while the heart is pumping the blood. The changing blood volume with heartbeats results in a train of pulses at the output of ldr. We can simply say that if the rate of heart beat is high then the Green led will blink faster.