Active In SP
Joined: Sep 2010
12-01-2011, 04:10 PM
The Heart Beat Sensor provides a simple way to study the heart's function.
This sensor monitors the flow of blood through ear lobe. As the heart forces
blood through the blood vessels in the ear lobe, the amount of blood in the
ear changes with time. The sensor shines a light lobe (small incandescent
lamp) through the ear and measures the light that is transmitted. The clip can
also be used on a fingertip or on the web of skin between the thumb and
index finger. The signal is amplified, inverted and filtered, in the box.
By graphing this signal, the heart rate can be determined, and some details of
the pumping action of the heart can be seen on the graph.
Joined: Apr 2012
25-07-2012, 09:52 AM
Heart Beat Sensor
working 1.pdf (Size: 560.25 KB / Downloads: 106)
digital output of heat beat when a finger is
placed on it. When the heart beat detector
is working, the beat LED flashes in unison
with each heart beat. This digital output
can be connected to microcontroller
directly to measure the Beats Per Minute
(BPM) rate. It works on the principle of
light modulation by blood flow through
finger at each pulse.
Using the Sensor
· Connect regulated DC power supply of 5 Volts. Black wire is Ground, Next middle wire is
Brown which is output and Red wire is positive supply. These wires are also marked on PCB.
· To test sensor you only need power the sensor by connect two wires +5V and GND. You can
leave the output wire as it is. When Beat LED is off the output is at 0V.
· Put finger on the marked position, and you can view the beat LED blinking on each heart
· The output is active high for each beat and can be given directly to microcontroller for
The sensor consists of a super bright red LED
and light detector. The LED needs to be super
bright as the maximum light must pass spread in
finger and detected by detector. Now, when the
heart pumps a pulse of blood through the blood
vessels, the finger becomes slightly more opaque
and so less light reached the detector. With each
heart pulse the detector signal varies. This
variation is converted to electrical pulse. This
signal is amplified and triggered through an
amplifier which outputs +5V logic level signal.
The output signal is also indicated by a LED
which blinks on each heart beat.