- Thumb sized heart rate monitor designed for Arduino microcontrollers
- Detects blood volume changing in the microvascular bed of tissues
- Can be worn on a wrist, a finger, a earlobe or any other areas in contact with skin
- Two holes to attach to the included belt
- Compatible with Raspberry Pi, Intel Edison, Joule and Curie
The Gravity Heart Rate Monitor Sensor for Arduino is a thumb-sized heart rate monitor designed for Arduino microcontrollers.

The Gravity Heart Rate Monitor Sensor for Arduino is a pulse sensor which is developed based on PPG (PhotoPlethysmoGraphy) techniques. This is a simple and low-cost optical technique that can be used to detect blood volume changing in the micro vascular bed of tissues. It is relatively easy to detect the pulsatile component of the cardiac cycle according to this theory.

The Gravity Heart Rate Monitor Sensor for Arduino has two holes that you can use to attach to your belt. You can wrap on your finger, wrist, earlobe or other areas where it has contact with skin.