The Breath sensor:

Finally I installed the breath sensor with thanks to Freescale for sending

me the right sensors. It is hard to see in the picture, but there is a dual

pressure sensor on the second mouthpiece, that will be replaced by a

plastic version in the future.

Measuring my own breath I found that I could generate about 10 kPa

overpressure. It is not nice though to just give pressure and not to blow.

There is a small rubber cork in the throat of the mouthpiece. In this

cork are 4 holes (ø 3mm). 1 for the pressure sensor and 3 to give the air

room to flow. It is much harder to build up pressure now so I changed

from the MPXV7007DP to the MPXV7002DP.

You can not only blow in the sensor but you can also draw (which I

sometimes do on the real trumpet as well). I see this as two separate

controller parameters. Output values bigger than 2.5V mean blowing and

output values smaller mean drawing.

The first results are promising.