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Out of Body

October 12, 2010

I’ve been getting a little bogged down in trying to get accurate data and visualization of my heart rate, so I took a step back this weekend to get some perspective on my project as a whole. Sometimes doing something seemingly entirely unrelated can help achieve this better than simply facing it head on.

Sunday morning I got up at 4:00 am and went to help John Ninomiya prepare for his cluster balloon flight from Canaan, Connecticut, along with a small army of other volunteers.

Here’s John in the harness.  Those are water bags hanging at his waste, which he will have to discharge to rise.  To sink, he’ll have to cut some balloons loose.

Heading northeast into Massachusetts:

The warming sun is melting the frozen dew on the balloons, John is rising rapidly, and his altitude is getting harder to control.  The clearings northeast of here are very small, so John decides to come down in Three Mile Field:

Afterwards they let us all have a try in the harness and go up 30 feet or so:

And here I am:

So what’s this got to do with Rest of You?  The best way I’ve been able to describe ballooning is that it is like seeing the world in a dream.  We are not accustomed to seeing it unfold beneath us from that vantage point unless we are looking through a framed plate of glass.  In much the same way, we are not accustomed to seeing ourselves asleep.  We have an idea of what it looks like, a snapshot, but it is not a state with which we are as familiar as our waking day-to-day existence.  I have framed this investigation as an ongoing study of my sleep patterns, with special attention to sleep apnea.  I was diagnosed with a mild version of this on the basis of two nights in a sleep center, and I would like to see what it looks like on a continuous basis.  Being up in a balloon, though, makes me realize that my aim is a little more poetic though, that I really want to be outside my body, looking down on it.

And what’s this got to do with the category “Wear It”?  John has built up a remarkably complex tool for interacting physically with the environment out of a combination of very simple elements: a harness for attaching everything to his body, balloons, zip ties, nylon cord, water bags and assorted peripheral devices for communication and recording the experience.

His project has a clear aim, and the execution was well-planned.  In that light, I’ve given more thought to the entire project of my own Out of Body Experience.  There are three main components:

  1. What is being measured
  2. How is it being measured
  3. What is the story to be told with these measurements

What is being measured

  • Motion
  • Respiration
  • Heart rate
  • Noise

How is it being measured

  • Motion: I am setting up an Axis security camera above my bed with motion detection triggering an email with jpeg’s of my physical state at that moment.
  • Respiration: I have ordered stretch sensor material (, and will attach this to 2 or 3 straps around my torso and stomach.  The straps will have to be fairly inflexible, but have a slip joint bridged by elastic and the sensor.  As the sensor expands, the resistance goes up, and I will calibrate this to establish a respiration rate.
  • Heart rate: I’ve been working on this circuit, and am exploring a number of avenues. I’ll go into these in detail later:
    • Eric Rosenthal showed me another circuit than the one I described last week with a different Op Amp (LM358), but the output still needs to be smoothed with software.
    • Sean Montgomery’s analog circuit and the one with the Polar Wearlink+ as a backup in case I can’t get the first working in time (  I’ve ordered all the parts, and they should be here today.
    • Justin Down’s IR heart rate circuit detailed at ITP’s sensor wiki (
  • Noise: I started playing around with a couple of iPhone apps, and I’m getting something from one called “Owl”.  It’s got some problems, though, which I will go into later:

The major problem here is that it is impossible to set a baseline filter.  To improve on the accuracy of a sensor like this, I think I’ll have to build something with the Arduino.

What is the story

I expect the security camera to give me the quickest feedback on what I look like while I sleep and how much I thrash about.  I expect my rate of respiration to ultimately be the most enlightening, though, especially compared to my heart rate, as the issue with apnea is primarily the failure to breathe.  I intend to wear this during the day as well to see how much it varies, and if and how much I hold my breath then too.

Visualizing all of this, whether on the screen or physically, is critical in telling this story.  I have a number of half-baked ideas, and would like to come back to this topic shortly after they’ve had a little more time.


From → ITP, Rest of You

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