The team at Interactive Matter were tasked with building a circuit to measure the human pulse, however their client had certain requirements which caused the development to be a little different than expected. The plan was to use a popular Arduino-based solution which seemed like a good idea at the start, however it was not to be.
However through a process of trial and error, the designers used a mixture of op-amps and filters to solve their problem and produce a working solution. Their article is an interesting journey of mixing analog electronics and as well as digital potentiometers and other systems to create what is an educational description of combining analog electronics with an Arduino.
When building such projects using a solderless breadboard, you can minimise space and still keep full Arduino-compatibility by using our Freetronics LeoStick - one of the smallest Arduino-compatible boards on the market:
But for more information on how to build your own pulse-rate monitor, head over to the Interactive Matter website.