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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shshistiem
Wed Sep 12 2018, 10:58 PM
hii!! some1 please let me know how i ll get rfid code to 8051 by WEIGAND mode
DrNossberg
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is there anyone here?
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bun
Hello everyone!
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By using a 555 timer how can I expand the range of the mobile phone jammer? Please reply me asap
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how to write and execute a program that read the keypad button and display the number on 7 segment on intel8051 at89s52 in assembly language?
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sir iwant to ask about controller of three phase supply by using back to back thyristor instead of triac....will u give me some guideline?
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kaiserslautern
Hello everyone, using software uart is a very good idea for a second serial port. Thank you so much. I would kindly like to know how to connect this port to the PC?
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PCBindex
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ExperimenterUK Avatar
Posted By ExperimenterUK
Thu Sep 13 2018, 08:39 PM
First of all, by reading your reply, I abandoned m...
DrNossberg Avatar
Posted By DrNossberg
Thu Sep 13 2018, 03:49 PM
Hi, thanks you for your reply ^^ First of all, by ...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Sep 12 2018, 12:12 AM
HiThere are several issues here.The original 8051 ...
DrNossberg Avatar
Posted By DrNossberg
Tue Sep 11 2018, 08:08 PM
Hello everybody!First of all let me explain some s...
ExperimenterUK Avatar
Posted By ExperimenterUK
Fri Sep 07 2018, 05:08 AM
The compiler thinks the micro doesn't have enough...
Sudhansudeep Avatar
Posted By Sudhansudeep
Fri Sep 07 2018, 02:59 AM
this is the build output message
Sudhansudeep Avatar
Posted By Sudhansudeep
Fri Sep 07 2018, 01:38 AM
Change the mobile number as [number removed] in t...
ExperimenterUK Avatar
Posted By ExperimenterUK
Thu Sep 06 2018, 08:56 PM
I don't know what the problem is, I get no errors....
Sudhansudeep Avatar
Posted By Sudhansudeep
Thu Sep 06 2018, 01:12 PM
the code is Attachment ...
Sudhansudeep Avatar
Posted By Sudhansudeep
Thu Sep 06 2018, 12:48 PM
the code is same as u sent me for 16 chars