Hi Dave,

Fianlly have usable numbers to work with, had some issues using a 3.3v reference as the sensor only works to 3V so I bought a LM317 adjustable reg and got it set to 3.00V, now it is working as per you calculations, :-) only thing im need to change a bit is the air density constant based on the altitude, temp and humidity.

the reveal, :-) basically what I am doing with this sesnor and program is setting it up in my RC plane to drop the flaps in relation to the airspeed, so as the airspeed decreases the flaps increase, and then as airspeed increases the flaps decrease. was driving in the car with the GPS, PIC and 2 servos connected and they seem to be reacting as I want them.

Will post a clip when I get a second hand to hold the cammera while I drive, :-)

Kind regards
Rob