Adding more sensors: breathing detection

• SPO2 seemed doomed, so I looked into detecting breathing.

• Measuring airflow from the nose seemed like the obvious way to go.

• The wind sensor from modern devices is actually sensitive enough that it can be made to work.

• http://shop.moderndevice.com/products/wind-sensor

• I got some nose cannula online, and technically they are medical instruments with sale restrictions. At least it's not as bad as trying to find syringes to refill cartridges.

• While I'm not fond of nose cannula, I figured I had to try that first.

• The modern devices output could conveniently be tuned to output between 0 and Vcc, trivial to read on an arduino analog pin.