After getting my little photo sensor ([1] one of theses) attached to my PIC I started playing with it using a torch and my little finger i can sometimes pick up a pulse but it is very sensitive to movement and the pulse only shows up in the 2 LSBs. This problem may be alleviated somewhat when measuring form inside someone. Anyhoo that is a problem to be sorted when I have a willing subject to test on.

But that aside, the electromyograph idea still needed a bit of thinking before anything could be built and I had no Idea if the output from it could be useful. Then I found [2] this. Looks like we may be onto something here. All I need now is the person and the electrodes. Oh and the amplifier hardware. Oh and a data logging device. Hmmm… This is turning into a bit of a big project.