Counting Heartbeat with Arduino: Help with Code?

I got a premade heartbeat sensor which uses an IR led and an IR receiver to sense heartbeat. It gives out an analog signal, which i have connected to my Arduino's A0 pin, and uploaded the analogRead sketch to it(sends values to serial port too).

Then to visualize the heartbeat i used a processing graph program that took the values from the serial port. When i place my finger on the sensor,  i get this graph shown below:  

Yes its very clear, but can anyone help me with the code? it just needs to measure the beats per minute, and store it in a variable. 

** The spike in the grph showing the pulse varies in height sometimes. So the code should calbrate and all. Also there is a 1-2 second delay before the clean pulse comes...

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DIYkaboss1 year ago
RD52 years ago

Hi, I'm working on a very similar project and I would like to know if you found a solution..

How can we measure the BPM??

Please help :)

You could clean the signal up with a comparator and use the freqmeas library for the arduino.

DangerousTim (author)  steveastrouk3 years ago

it already usues 2 opamps... i would love it if someone showed how to clean the signal in the software itself

work out the mean of the signal, if level > mean result=1 if level <= mean result=0