MDS

Since the input to the ADC is 0 - 3.3V you will have to scale the voltage through a voltage devider. + 12V as max input | / \ / Resitor 1.1K Ohm \ |----------------ADC input / \ / Resitor 420 Ohm \ ---- GND -- This will give you a 10bit voltage resolution for 0 - 12V V = ADC-VAL * .0117

arduino and netduino take the same shields. If u get the sparkfun lib it has the shield in the lib.

Have you tryed the Pulse Width Modulator. Thats the type of thing the PWM is designed for.

The chip has a 12bit ADC on it @12 bit it reads in a resolution of .000805V thats 3.3V / 4096. So just take the number from the analog channel and multiply it by .000805 for the voltage. 150mV would be 186 form the analog channel.

You really need to scale the 5V down to 3.3V even if the pins can take 5V your readings wont be acurate. I would also say to you that you should put the input through a voltage follower before you go into the voltage devider. If the reading is critical you dont want a voltage spike frying the ADC channel. Its good practice to use voltage followers for all external sources. If your looking to make sure that the presure does not go above a known value you can also use a voltage comparitor with the output going to one of the digital pins. The comparitor is an opamp so it acts like a voltage follower to protect the processor.