Recording of heartbeat through measure of the transparancy of the thumb.

The scale on top is in seconds.

This is my own heartbeat, and my own recording, using open source program Audacity.
I took a 6V, 3W light bulb (used in bicycles) on the top side of my thumb (on my nail), and a infrared sensordiode on the other side of my thumb. The infrared diode was connected to the microphone input of a mp3-stick. The microphone input supplied the voltage (as if it was a elektret microphone). The recording was read into Audacity, and the signal was enlarged en filtered with a low-pass filter at 3Hz (twice).

Public domain.

Ich, der Urheberrechtsinhaber dieses Werkes, veröffentliche es als gemeinfrei. Dies gilt weltweit. In manchen Staaten könnte dies rechtlich nicht möglich sein. Sofern dies der Fall ist: Ich gewähre jedem das bedingungslose Recht, dieses Werk für jedweden Zweck zu nutzen, es sei denn, Bedingungen sind gesetzlich erforderlich.