Interface 8/8/8 and FS2Phidget 4315

Hello ALL, I am trying to interface my analog Altimeter gauge to FSX. I would like to drive the gauge with my small motor and gearbox. Can anyone look at the below, very crude idea and help me to use FS2Phidget FSVariable to achieve something like this? This portion only illustrates a Positive climb, forward motor movement. Need to also provide a reverse motor movement, AM = AM - 1.

FSXO= FSX Offset for altitude, a number between 0 and 10,000.
AM= a counter for the Altitude Motor controlling logic.

50 AM = 0
10 if AM=FSXO then goto 100
20 AM=AM + 1
30 turn on motor
40 goto 10

100 turn motor off
110 goto 10

Thinking:

If FSX aircraft is at sea level then FSXO ~20
the above circuit (10) checks if AM counter matches, if not then goes to (20) makes AM=1, (30) turns on the motor, (40) goes back to (10) and continues until (10) is TRUE, AM=20, then goes to (100) and turns the motor OFF.

I just do not know how to ask FS2Phidget to do this.

What do you think?

Gary