Of all the body responses one could monitor, heart rate is one of the most important because it fluctuates greatly depending on our state of mind and physical condition. Heart rate during physical activity gives us a direct indication of our fitness level, and heart rate changes throughout the night can be clear indicators of when a dream cycle has begun. A heart rate monitor is also a very easy device to use for extended periods because it can
be placed on the body in such a way that is not uncomfortable or in the way of any normal activity.

The heart rate monitor project presented here uses a sensitive light-detecting resistor to detect small changes in the light beaming through your finger as your blood pumps through the tiny arteries in the finger. This device is not the same as the heart rate monitors typically used in hospitals because those use skin probes that detect changes in electrical activity as the heart beats. This heart rate monitor actually “sees” your pulse through the body, so it can be used on a finger, toe, or even your earlobe.

The heart rate monitor is a combination of analog and digital circuitry, as shown below.



The LM324 quad op amp (IC1) forms a sensitive amplifier and a low-pass filter that will “lock” onto tiny variations in voltage that fall within the typical heart rate frequencies. The varying voltage comes from the light-dependent resistor (LDR), which changes a very small amount each time blood pumps through the tiny arteries in between the visible red LED and the LDR surface.




Complete Design



Insert Your Fingure Here







if you feel any doubt or need further details feel free to use Forum.
Source: Evil Genius MPP Issue 2010
[Submitted by coolmirza143]
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Wed Aug 24 2016, 11:00 PM
Goodnews
pls i need a project writeup on LED scrolling message display using microcontroller
Mon Aug 01 2016, 03:25 PM
Manu Mishra
hi guys if u need c code for SD card interfacing with p89v51rd2 8051 controller system u can see the video of the project and the download the c code form blog http://embeddedinrajasthan.blogspot.in/?view=classic
Mon Aug 01 2016, 03:23 PM
Manu Mishra
hi guys if u need c code for finger print security system u can see the video of the project and the download the c code form blog http://embeddedinrajasthan.blogspot.in/?view=classic
ExperimenterUK
Tue Jul 19 2016, 05:59 PM
@mhammad 64 bits is 8 bytes.
Tue Jul 19 2016, 07:56 AM
mhammad kassem
hello! i want to know how to use UART in mikroc , I want to receive 64 bits from another microcontroller and i dont know how to start my code to receive the 64 bits...any help?
ExperimenterUK
Mon Jul 18 2016, 08:32 PM
@meena.. are you still having trouble ?
Sat Jul 16 2016, 10:19 AM
Meena
problem in loading email address while registering.Please help
Sun Jul 10 2016, 02:50 PM
shockwave
could you please provide a sample code that controling LED using bluetooth HC-05 interfacing pic16f877a thank you!
Sun Jul 10 2016, 02:49 PM
shockwave
Help!
ExperimenterUK
Sat Jul 09 2016, 05:25 PM
@Santhana krishnan post in forum to discuss your problem

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rajavarmanslr Avatar
Posted By rajavarmanslr
Thu Aug 18 2016, 01:40 PM
I have two 8051 that interfaces with nRF24l01. One...
rajavarmanslr Avatar
Posted By rajavarmanslr
Thu Aug 18 2016, 12:31 PM
I have two 8051 that interfaces with nRF24l01. One...
ExperimenterUK Avatar
Posted By ExperimenterUK
Mon Aug 01 2016, 05:26 AM
is working nowugoo5000Great, thanks for letting u...
ugoo5000 Avatar
Posted By ugoo5000
Sat Jul 30 2016, 07:31 AM
is working noworg 00hmov p1,#11111111bmov p3,#1111...
ugoo5000 Avatar
Posted By ugoo5000
Sat Jul 30 2016, 06:40 AM
when i press a button in p3.0,the counter will st...
ugoo5000 Avatar
Posted By ugoo5000
Sat Jul 30 2016, 06:30 AM
proteus file Attachment ...
ExperimenterUK Avatar
Posted By ExperimenterUK
Fri Jul 29 2016, 11:34 PM
Your code does not count at all, it produces a one...
ugoo5000 Avatar
Posted By ugoo5000
Fri Jul 29 2016, 07:49 PM
i want the the counter to be counting in secs with...
ExperimenterUK Avatar
Posted By ExperimenterUK
Fri Jul 29 2016, 07:31 PM
HiYour Proteus file did not upload, be sure to zip...
ugoo5000 Avatar
Posted By ugoo5000
Fri Jul 29 2016, 11:50 AM
below is the proteus file