Pulse Rate Measurement System

I had a project kit for the above project and it used a pulse rate sensor that was clipped to the ear lobe for sensing. I think the sensor had some IR reflection type sensor, its damaged now. I want to try making a sensor myself, but dont have much idea about this, can anyone help me with some start off information.

http://www.ingenstech.com/projects/puls … nt-system/

https://www.sparkfun.com/products/11574

Look at the schematic and comments.

http://dlnmh9ip6v2uc.cloudfront.net/dat … ematic.pdf

Also read the design blogs …

http://flipthatbit.net/2011/04/simple-pulsoximeter/

http://pulsesensor.myshopify.com/pages/open-hardware