Blood Volume Pulse (BVP)
It is a well known fact, that the heartbeat of a person is linked to their emotional state and feelings. When excited or in love, our hearts will beat faster, and when we are calm or bored, it will beat slower in comparison. Heartbeat is perhaps the most well known way of measuring a person emotions and emotional state.
Plethysmogram is a measurement of changing volume in the body. This can measure instances such as blood circulation in the fingers, which with great certainty can be used to discover a persons Heart Rate (HR) and Heart Rate Variability (HRV). Photoplethysmogram is a plethysmogram optically obtained. We use a LED diode, and a light sensor, shining light through the finger measuring the light transmitted through the finger. This data can then be translated into information about the users Heart Rate (HR).