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Heart Beat Counter [on LCD] - msp430g2553

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This is a heart beat counter, which displays the result on an LCD, it amplifies the signal by a dual op amp IC, and passes it to msp, as an interupt to count the number of pulse for 15 secs, it uses internal clock, so its not so accurate, but it will give you a good precised result...

i have given all the neccassary information, including the schematic, the video link, and the code, with the header file..

here is its video...



see the instructions to build it at














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the ir pair should be 1 led and 1 ir sensor (photo diode? still a diode?)


the vishay tcrt5000 is convenient to use as it comes in a single package and aligned already. it can be have in ebay for a few dollars (multiple units).


i used that for proximity detection but it could also be used here for pulse sensing with op-amps.




did u try just use the 3.6v from launchpad? the lm324/358 should work w/ 3v. any reason u need 5v?

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thanks to all of you friends...





the pair consists of an IR led and a PHOTODIODE, because ir can penetrate through human body more easily [i think] and the pulse generated by the heart affects the reception, which is then amplified and filtered by 2 op amp amplification stages, and then given to the msp430....





it was necessary to give 5 volts, as the LCD works on 5 volts, and decreasing the voltage in the sensor section means decreasing the voltage for the IR, which effects the sensitivity... i have given nearly 4 volts to msp, [using 3 diodes in series]



what is HR? 

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