control car AC/heater(mechanical) knobs with servos/stepper motor??

Projects General Guidance
1

hello forum. so my situation is this :

i want to be able to control my car ac/heating system, via an arduino board.
this system consists of the following:
AC switch ( i can directly control it via a relay)
Motor blower knob. ( i can completly remove the knob, and produce the electrical signals, with signals produced by the arduino)

hotter-colder knob. the one which controls the "heat" of the air...
airflow direction knob. the knob that controls, which vents the air comes through...
so the catch is this: the two last knobs, are completly mechanical.... meaning, they completly push-pull wires, that go inside the heating assembly...... i really dont want to touch any of the heating assembly, so i was thinking this : just attach to the knobs a servo/stepper, to turn the knobs, "As would my hand do".

( i have plenty of space to hide all that, so dont worry about visual)

so how do you guys think i could do this?? i really havent worked again with either servos, nor stepper motors... the
both knobs, have to move about 270 degrees....
( http://i15.tinypic.com/2w4e792.jpg)
i know that most servos can go only abotu 180:/

also, would the stepper/servos, by able to produce enough torque to turn those knobs??

2

it seems that the best option would be to have a servo that goes 360degrees... any way to convert one??

3

settra:
it seems that the best option would be to have a servo that goes 360degrees... any way to convert one??

Yes, just search for "continuous rotation servo" (continuous rotation servo - Google Search)

4

cooool! you where right. in my place i can easily get my hands on that:
https://www.sparkfun.com/datasheets/Robotics/servo-360_e.pdf (The sm4303R version)..

so i control them the same way as the normal servos?? 1ms pulse, for -180degres and 2ms for +180???

the only problem is its 4.8kg.cm, and i do not really have any idea if this is enough or not.... :confused: any ideas how i could check that?