The infrared detectors of the DiY cardiac sensor. Screenshot. © DR
Sporty, curious, worried? And what if you made your cardiac sensor yourself?
The wave of the quantified self (or the analysis of one’s own data) is not sparing the DiY movement. The cardiac sensor is a good example. It offers solutions that are more or less easy to make yourself to analyse your beat. Collin Cunningham from Makezine.com developed a technique to build a cardiac sensor with the help of an Arduino, an infrared LED and an infrared sensor. For each heartbeat, new oxygen-saturated blood leaves the heart to circulate through the body. Fluctuations in blood oxygenation modify the quantity of infrared light going from the LED to the sensor. A principle called pulse oximetry, DiY version.
By placing the infrared emitter and detector in front of your finger, you can pick up the regular variations of the oxygen saturation of the blood. The Arduino analyses these fluctuations to graphically transpose heartbeats (for a graphic display of the data picked up by the Arduino, you need to go through a display of the curve system via Processing or MaxMSP, see over here for a tutorial).
Patients suffering from arrhythmia, top-level sportsmen needing to monitor their performances or even obese people could resort to this kind of inexpensive apparatus. Beware nevertheless of questionable interpretations (one hardly learns how to read the results of an ECG in school)…
However this type of apparatus could also be used by video games designers or developers for any interactive device.
Tutorial to make your cardiac sensor:
Heartbeat sensor in bracelet mode, for confirmed makers
DiY cardiac sensor, “clothes peg” version