For my final I wanted to pick up on the control report that I did for the class' library (pressure transducer). My intent was to make a control out of water, but I soon discovered that fabricating said control would need a lot of precise trial an error in order to control: the flux of water, its containment and its proper messure, not to mention be sure that non of the liquid escaped into the electronics.
So in order to conduct a more controlable experiment I decided to use air. And since I had to messure pressure diference in order to get readings I was attaching to one end of my pressure reader a seringe and to the other an inflated ballon (mostly inspired by my professor Tom Igoe who had repeatedly suggested using ballons or air pumps to create a weee-woo efect in light). So that by mantaining a constant pressure on the seringe end I could map the change of pressure in the ballon and use this difference to trigger a HIGH in a digital pin.
The example circuit and sketch I initially used were adapted from a project meant to measure the amount of water poured into a water container. This project intended to send the information through a wifi shield into a server, but since I was not using that I removed everything else in the sketch and just monitored the readings.
After getting the proper readings I went ahead and attachend the ballon to one end of the pressure transducer and a seringe on the other. So in order to manage this readings I directly used the free hand calibration example from Arduino, I stuck to this sketch and focused more on the fabrication, trying to understand how to get to a more or less controllable stage, and most importantly: getting an LED inside a ballon.