Collin Cunningham of MAKE builds an infrared heart monitor

I love the electronics videos Collin Cunningham produces for Make: Online. Not only does he describe his projects in an entertaining way, he also scores the trippy music for them.

After checking out a few projects involving IR heart monitors, I decided to have a go at the interface myself. Seen above are the results of my first experimentation with pulse oximetry. Getting the setup up and running satisfactorily required a bit more time and tinkering than I'd expected - especially after reversing a premature mod to my emitter/detector pair. The next version I try will either use a higher output emitter (see Charles Martin's version) or some amplification hardware (as used in Meng Li's sensor).

Collin's Lab: Infrared heart sensor


  1. This technology has been around a while. My BME/EE majoring girlfriend in college made one freshman year 1981

  2. Use it to monitor your heart rate while you sleep. Then after a couple of days of data you will be able to figure your REM sleep pattern. Once you have this you can write a program to send a signal that you are dreaming (light flash etc) and you can be come a lucid dreamer. There was a commercial device that did just this feature, but it bounced the IR off the eyelid to determine the Rapid Eye Movement.

  3. This is really interesting to me. I’m an obsessive cyclist, and race nearly every weekend. I’ve been training with a heart monitor daily for the last 4 years. What’s strange to me is I spent a nice chunk of change on a Polar HRM/Cycling computer (189 USD). For it to interface with my Mac, and download the data, I had a to buy a piece of 3rd party software (iSmartTrain – great program), but the monitor sends the data by sound, sort of like an old school modem. It fails about 50% of the time, so I often have to keep trying to get the data on to my Mac. This great article makes me think Polar is holding out on us, and ripping us off. Thanks for the perspective.

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