Run, Christina, Run!
A couple of weekends ago we set up in a studio space on the east side of Austin, TX to see what it sounds like when you combine a girl, a treadmill, a heart rate monitor, and a fun little puredata patch. The video is still being processed but here’s a picture of two of the four elements involved; the rest is forthcoming.
So, you just bought a polar heart rate monitor interface (HRMI) from Sparkfun.com? Awesome, so did I. What’s that? You want to know how to use Pure Data (PD) to grab the data off of the USB connection so you can use it for cool stuff later on? Perfect – I have just the patch for you. First, you’ll need the latest version of PD-extended. Got it? Okay, next you’ll need the PdMtl Abstractions Library. PdMtl is great because it’s going to take the serial ASCII data that we get from the USB connection and convert it into standard PD lists that can be easily manipulated. So, now that you have those two bits installed, here’s the HRMI Patch that pulls it all together.
A Screenshot of the HRMI patch
Strap your Polar heart rate monitor on, plug in the HRMI via USB, adjust the comport if need be (it should point to the USB port the HRMI is plugged into) and hit the toggle at the top of the patch. The metro object should start polling the HRMI once every second with the results displayed in the numbers at the bottom of the patch. The first number is the status byte, the second is the count, and the third is the solid gold we’re looking for – our heart rate in beats per minute as averaged by the magic of the HRMI. There you have it; as for application, that’ll come later but in the mean time play around with it and see what fun stuff you can control using only your squishy ticker.