Trying to design a system that provides 0v-4v voltage on one wire, and invers 4-0v on another.

[WeldedRing]

Hey guys,

First post, thanks for your help.

A friend came to me with an interesting project he is working on. It is a cruise control for an off-road motorcycle. The throttle is controlled by two pots. One pot gives variable voltage of 0v-4v the other gives a inverse voltage of 4v-0v (At full throttle it is 4v/0v, at idle it is 0v/4v). This feeds right into the ECU. I've mostly got it figured out with an Arduino and a couple of digipots, but I know there has to be a simpler way.

input: 0-4v
output: 4-0v

I'm wondering if it is possible to create a circuit that will recreate this without microcontrollers, and what I would search for to find out more about building one. I am VERY comfortable with circuit building and soldering. I just have NO IDEA what to search for to find out about such a circuit.

Thanks in advance!

 

[Bluejets]

Seems you already have it with a dual gang pot.
Wire the 4V to one side of one pot (say terminal 1) and the opposite side of the other pot.(say terminal 3)
Ground the same only to terminal 3 on the first and terminal 1 on the other.
Two signals (one from each pot terminal 2)will then be opposite as the common shaft is rotated.

At least, that's the way I read your query.......

Edit:- the above I was referring to linear pots as opposed to log pots.

 

[Alec_t]

I agree with Bluejets. It just remains to choose the pot value. 5k perhaps?