switch 3 references voltage for my servo position

Question

I have some positioning servo driver and servo with pot feedback. Now I try to build circuit to switch between 3 positions. For testing I just use 3 way switch and 3 pots as voltage reference, but in my destination project my switch will by 10 meters away from servo and driver so current circuit may be noisy. So can I build this without passing ref. voltage thru switch? Or using buttons?

Answer 1

Your servo remains in an undefined state if all three switches are open-circuit. A simpler arrangement using two switches leaves the servo at its mid-position in a fairly low-noise condition, because both remote switches are open-circuit.

R1 defines the default state, while R2 pulls up toward +5V, and R3 pulls down toward ground. The switch chip and variable resistors can lie close to the servo, while the logic control signals can be remote. Be aware that the switch chip requires a logic supply and ground connection (not shown).

^{simulate this circuit – Schematic created using CircuitLab}
If you really need the servo in an undefined state, a quad-switch like 74HC4066 can be used (one-of-four unused). As before, control signals can be remote, while analog servo voltages can be more closely associated with the servo:

^{simulate this circuit}