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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Tue Aug 19 2014, 04:51 PM
allen ndumu
please i will like to know if the problem of speed control of dc motor using keypad and l298 was if yes can i have the complete project send it to the address i really need to see it
Tue Aug 19 2014, 10:47 AM
Amit Bisht
sir i want to have some trending projects on which i could work related to ATmega 16 microcontroller
ExperimenterUK
Sat Aug 16 2014, 04:16 PM
@diligent . create a thread
Sat Aug 16 2014, 03:17 PM
diligent
in assembly langauage programming..
Sat Aug 16 2014, 03:14 PM
diligent
will anyone help me?
Thu Aug 14 2014, 10:24 PM
Amirudin Tone
i help, i need liberary IC 4047 in the proteus. thanks
ExperimenterUK
Thu Aug 14 2014, 03:59 PM
@NARAYANA are you getting an error ?
Tue Aug 12 2014, 11:47 PM
NARAYANA
i am not able to get reg please provide me registration link
Tue Aug 12 2014, 10:32 AM
saloni
sir I was needing literature survey of''ANDROID CONTROLLED SPY ROBOT USING MICROCONTROLLER"
ajay_bhargav
Mon Aug 11 2014, 12:30 PM
@nisargpatel and @NARAYANA please post questions in forum.

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samchovatiya
Thu Aug 21 2014, 02:30 PM
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gaurav7577 Avatar
Posted By gaurav7577
Fri Aug 22 2014, 01:30 AM
thnks for rply..i hav attached error pic here...pl...
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Posted By ajay_bhargav
Fri Aug 22 2014, 12:46 AM
It is clearly mention with segment name on the pin...
ajay_bhargav Avatar
Posted By ajay_bhargav
Fri Aug 22 2014, 12:42 AM
What is the error that you're getting?
samchovatiya Avatar
Posted By samchovatiya
Thu Aug 21 2014, 02:57 PM
I want to know that in my project of Simple Digita...
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Posted By gaurav7577
Thu Aug 21 2014, 05:47 AM
Hi..I hav lpc 2148 dev board from nex Robotics. I ...
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Posted By hasmukhjain
Thu Aug 21 2014, 01:50 AM
for that try to add a variable wch can save your p...
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Posted By jayachandra
Wed Aug 20 2014, 08:11 AM
thanq for reply @hasmukhjain,actually my applicati...
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Posted By hasmukhjain
Wed Aug 20 2014, 06:40 AM
Hi Mr jayachandra,I feel ur if statement for switc...
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Posted By nisargpatel
Wed Aug 20 2014, 01:29 AM
see we are measuring electrical parameters by CT, ...
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Posted By jayachandra
Tue Aug 19 2014, 08:22 AM
HELLOim facing problem with eeprom, i wrote a prog...