Build your own pulsemeter
Close to Your Heart
© Lead Image © Nelli Valova, 123RF.com
A pulsemeter built with a Raspberry Pi, a digital-to-analog converter, and an optical sensor monitors your heart rate just as well as many far more expensive medical devices.
Monitoring your pulse helps you determine the health of your vascular system. If you are interested in fitness, it is one of the vital metrics in sports monitoring. Whether you are taking measurements out of scientific interest, as a metric to gauge the intensity of your workout, as a measure of fitness, or as a cautionary measure against excessive stress, a DIY pulsemeter provides quick and easy feedback.
The module used in the example here is based on an optical method that measures light absorption of the red blood cells in your veins to determine the rhythm of your heartbeat. Typically, you will want to deploy sensors like this at the wrist, the arch of the foot, temple, or neck, where the veins are just under the skin.
The sensor has an operating voltage of 3-5V, and the output voltage varies depending on how well you position the sensor. Occasionally, it will not output a value at all (e.g., if you press it against the skin so hard that it blocks the blood flow).
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia