Is there such thing as potentiometers that have a low resistance when centered and increasing resistances if you turn either left or right?
Edit: When i say centered, i mean that the pot is at zero resistance normally, when rotated clockwise, it will increase resistance. When rotated counter clockwise from the zero resistance position, it will also increase in resistance. Kind of like two pots put together in opposite directions.
Edit2: Well, specifically, I'm looking to modify a motor controller to give a nice smooth forward and reverse with a roll of the handle (think motorcycle throttle, except if you twist the other way, it reverses smoothly). I know the motor controller accepts a switch as forward/reverse and a pot as velocity control. Anyone ever encountered something like this?
Best Answer
I'll suggest something wacky, in case you don't want to or can't modify your pots. How about connecting two standard potentiometers together with a mechanism, such that twisting a knob moves one pot, and twisting the knob in the other direction moves the other pot?
One possible way to do this is to have two linear pots with their grounded connections next to each other and electrically connected. Imagine a piece that goes between the two pots and it connected to both pot inputs via an elastomer (i.e. just wrap a rubber band around the pieces). When you move to the right, one linear pot will move freely, while the other is stuck against the hard stop. But because its connection to the input you're moving is elastic, the connection just stretches and doesn't risk breaking the pot. When you slide back in the other direction, the pot that was originally able to move will bottom out against its hard stop, while the one that was previously bottomed out will now move freely.
It's a little corny but I thought I'd throw it out there anyway. I can post a sketch if you like. :)