A Maker by the name of “Bajdi” recently created a heartbeat sensor using a 2.2” TFT display and an ATmega328 MCU.
Inspired by a previous open hardware project, the Maker connected the sensor to an ATmega328 running at 3.3V and loaded an example code, which allowed the heartbeat to be seen on the Arduino serial monitor. The Maker then connected a 2.2″ TFT display to the ATmega328 to display the sensor output.
Atmel | Bits & Pieces 