This project by the undergraduate students of Cornell University allows you to measure your heart rate along with blood pressure through the use of optical based sensors. Their intention is to gather data for large-scale analysis for the automatic prediction of heart disease. The heart of the project is the ATMEGA 1284p, which is used to control the infrared LEDs that will transmit light which is reflected back to the light to frequency sensors.
The microcontroller takes in the signals that reflect pulsatile measurements, and will digitally process these signals into pulse measurements, and send the data through either USB or bluetooth to a PC. The PC will have a GUI that graphically shows the two pulses and the blood pressure and pulse. The mouse unit contains the mouse controller, a mega1284P microcontroller, an ultrasonic sound transmitter, three ultrasonic sound receivers and an XBEE wireless transceiver. The base station contains a mega32 microcontroller and an XBEE wireless transceiver. A GUI has also been created to observe the data without any use of additional tools. The complete mathematics along with the schematics of the project can be found on the project website.