When the sensor senses light it becomes more resistant causing the voltage reading in the serial monitor to go down.
Finger heartbeat detection sensor module.
This heart beat detection module uses bright infrared led and a photo transistor to detect the pulse of the finger red led flashes with each pulse.
Pulse monitor works as follows.
The led is the light side of the finger and phototransistor on the other side of the finger phototransistor used to obtain the flux emitted when the blood pressure pulse by the finger when the resistance of the phototransistor will be slight changed.
The led is turned on on one side of the finger and photo transistor is on the other side of the finger.
Pulse monitor works as follows.
The infrared sensor on the other side can then pick up slight changes in the light transmittance through your finger when blood is pumped in.
Ky 039 is a low cost heart beat sensing module.
This ky 039 finger detection heartbeat measuring sensor module uses bright infrared ir led and a phototransistor to detect the pulse of the finger a red led flashes with each pulse.
The sensor is made to shine an infrared led through your finger.