Stepper/servo motor control....

[Michael D. Porter]

A good long while ago, I mentioned that I was going to pick up a Lucas
mechanical fuel injection unit, and wanted to add barometric
compensation, and because of my location, I need to add this capacity.
The fuel injection system has a manual adjustment for mixture richness,
which I can use for adjusting for altitude.

I have determined that I can do what I need with a circuit to control a
stepper or servo motor from a variable resistance. What I need is a
motor/circuit combination which will provide an absolute position for a
given resistance. For reasons of cost, the cheapest means of input for
altitude is a barometric sensor for an L-Jetronic digital fuel injection
system--essentially, the input device is a sealed bellows with a strain
gauge inside. 

Is there an existing circuit available which does not require constant
microprocessor input and output? I simply need something to resolve a
given
resistance to a fixed position.

Any ideas on this? I'd like to avoid having to provide position feedback
through an encoder. 

Cheers.