Kyto Optical Heartbeat sensor - Ear clip - HRM-2511B

With this optical sensor from Kyto you can measure your heart rate. The heart rate sensor is intended to be used as an ear clip.

For more information on the specifications see the following page's:
Ear clip infrared heart rate pulse sensor - KYTO2511B   (product page. For more information, it is possible to contact Kyto on this page)
Heart Rate Monitor Instructables   (explanation with separate IR transmitter and receiver, but applicable to this product)