Slide Potentiometer

The Vex Potentiometers are great for easy absolute angle sensing, but there have been a few cases where it would have been more convenient to have a slide potentiometer for measuring linear movement.

I’d love to see a Vex slide potentiometer with a 2" to 4" slide length. Working out the attachment method for the traveler might be a bit tricky, but the folks at IFI are plenty clever to figure something out :wink:


  • Dean

For those that don’t know what a slide potentiometer looks like, here is a 100mm one (complements of DigiKey):

I bet you’ve already thought of this but you get the same use out of one of the current pots by gearing it to whatever is sliding. You would likely have to reduce the ratio but it would be very similar functionally.

True, but then you could not do something like this Pressure sensor fully assembled.

Right - In fact I’ve made a pressure sensor using this approach, but I never got the friction and slop down to a level I was happy with.

For mechanisms driven by a Vex motor, you can use a shaft encoder or rotary potentiometer easily enough, since the power is coming from a rotary source. In my case, I was making a force gauge, so the movement I was measuring was not otherwise available as a rotary motion.

Instead of a slide potentiometer, perhaps a pressure-sensitive version of the bumper switch would be of more general interest. That would have covered the case I needed, and it would be good for gripper fingers.


  • Dean

That’s an excellent Idea. Even though it would be possible to build one on your own, it would be much more convenient, not to mention more compatible with Vex, to have one designed by IFI. I’d buy it.

I’ll add it to the list of potential new products. I think there are a few things ahead of it in line, but who knows. :wink:

I guess you guys are a bit busy at the moment, but it never hurts to ask.

But, I just wanted to reiterate that perhaps a pressure sensitive bumper switch might be more generally useful and enabling than a slide potentiometer. Something that looks like a bumper switch but has one of these as the guts.


  • Dean

I would prefer the slide. You could potentially use it as pressure sensitive bumper as well.

I like the Force Sensing Resistor, the ideal thing to put inside the fingers of a gripper. From past experience they are sensitive to light loads, so they would be able to sense a foam block being held.