“Heart Beat Sensor” sounds very complicated to be made.But its not the reality, it is the most simplest medical device to make at home using very few components.
Components required to make a Heart Beat Sensor are:-
- Proximity Sensor
- LM 358 IC
- 4.7uF and 100nF Capacitors
- 47k,6.8k,680k, and 1k resistors.
- Some LEDs.
- First we need to connect the proximity sensor with transmitter in forward bias and receiver in reverse biased.
- After that fed the signal of from the receiver to High Pass Filter.
- Than amplify this signal by feeding the signal into Non Inverting Amplifier.
- Output of the amplifier will be pulses proportional to heart beat.
- If we want to fed the signal into controller, than we will require an additional buffer amplifier.
Now, discussing some theory of this circuit. Logic behind this is that when our heart beats, the blood circulates in our body. Due to this, their is minute volume change of blood on our index finger. Hence when we place our finger on the proximity sensor, that sensor senses that volume change and gives signal accordingly.