I’ve made some progress with the breathing_time hardware. Together with
Richard (I was his ‘lovely assistant’) we soldered all the parts on a
compact board. It will be much easier and more wearable to work with.
I’ve managed to program the first representation of breathing-time. This is
a sequence of the way the drop changes when I’m actually breathing while
wearing the stretch sensor. The dept of the breath determines the diameter
and alpha value of the ‘drop’. The breath rate determines the blurring and
horizontal position of the drop. Slow but deep breathing results in a soft
and blurry spot. I’ll post an example of fast breathing later.
For my breathing_time project I’m currently developing a script that’ll
represent breathing-time. It’s my first attempt at object oriented
programming (OOP) in Processing and it went rather smoothly. The pictures
are the first results using static data. Now I’m working on the ‘drops’
being affected by the data from the breath belt. Size, blurring and
transparency differ with very drop and will change with every new breath
detected. Parameters are depth of breath and breath rate.
I’ve upgraded my code for the stretch sensor graph in Processing. The sensor
outputs numbers. When I breath in or out the number gets lower. Detecting
breathing activity isn’t as easy as looking for a numbers below 200 for
example. Because over the time of wearing the sensor the whole range of
numbers starts to shift going either up or down. What remains is the sharp
decrease when breathing in. So now I’m comparing two averages of 5 rounds of
serial port activity each. When their difference is over 107% I know I’m
I’ve upgraded the first circuit with the potentiometers and the results look
promising. I used the Processing sketch that comes with the Arduino to make
a graphic of my breathing activity. I’ve tagged the different regions in the
graph so it’s easy to follow the movement of the breath. Btw the circuit is
constructed in such a way that the resistance decreases when the sensor is
stretched (breathing in.)
For this experiment I put the belt with the sensor rather tight around my
waist and I wasn’t talking. Talking makes the ‘not breathing’ part more
ragged but you can still clearly see when I’m breathing in and out.
During the TIK launch event I was fortunate to meet Christian Pointer. He’s an electronic engineer, programmer and hacker from Graz, Austria. He was very kind to help me with improving the stretch sensor. With the few parts I had with me he managed to increase the output range from the sensor to the Arduino dramaticly. Making it much easier for me to work the data and use it in different applications. The only thing I have to do is replace the two pot meters with ones’ of more suitable value and replace the simple opamp with a rail2rail one (TLV274 for example).
I shot a video at the normal framerate (view previous post.) I imported it into Flash and set the framerates using ActionScript. This way mocking breathing in and out and speeding up the frame rate. Not breathing slows down the framerate.