Optical heart rate monitor

Thread Starter


Joined Sep 28, 2011
I'm going to try and make this for a project. From what i understand you have to program the microcontroller? I wouldn't have a clue how to do this. Is there a site somewhere where I can learn how to do this? Thanks


Joined Sep 9, 2010
Are you hoping to show an oscilloscope-like trace like you see on TV, or just show the beating and perhaps show the rate numerically, like a pulse meter you'd use in the gym?


Joined Feb 1, 2010
If you Google 'UCSD Heart Rate Monitor' you can find a powerpoint with a similiar circuit to the one you posted there. IMO the phototransistor in the UCSD circuit works better than the photodiode.

They give you the PIC code, in C, in that link you posted. If you need to learn how to program a PIC microcontroller, then Googling that is a good start. There's lot of info on that out there.

Thread Starter


Joined Sep 28, 2011
Those ar every nice looking. The reason I'm going to do teh other is the guy who built it has a blog and email so you can ask questions if need be, althouhg is seems to take some time to get an answer.
Can someone tell me what 4.0M means under the microcontroller? thanks.


Joined Dec 20, 2007
The symbol shown as a Quartz Crystal is a 4.0MHz Quartz Crystal.
It is shown on almost every schematic on the datasheet for the PIC microcontroller.