Saturday, February 5, 2011

Heart rate measurement from fingertip

This projects describes an optical method to measure heart rate through fingertip. The volume of blood inside the finger artery varies with heartbeat. When an infrared light is passed through the fingertip, the amount of light absorbed is directly related to the blood volume. A photodiode senses this change in absorption and the signal is amplified further with a two stage filter/amplifier. The microcontroller reads the output from the amplifier and display the heart rate on a 3-digit seven segment LEDs.