I'm not sure how to phrase this. I'm looking for a potentiometer (10K) which can be pushed down like a button. As it is pushed down, the resistance changes. When released, it should move back up by itself, changing the resistance back to the resting value. Does such a pot exist?
EDIT - Also it would preferably be panel mount but I don't care.
EDIT - I don't care if the resistance gets higher or lower when it's pressed.
SPDT or DPDT push-pull potentiometer exist but they don't bounce back when they are release.
You can add resistor to the DPDT or SPDT pin to modulate the potentiometer response curve (linear / log) and change the resistance. This is common practice for electric guitar.
Maybe a bounce back switch wired before, after or in parallel of your pot could do what you want?
Here. Spring-loaded linear potentiometers. Shortest travel I see is about 0.8"
That said, from your description all you want is two resistance values, so that's easy enough to produce with two resistors and a pushbutton. And it'll cost less than $40.
[edit]
Here's a less expensive one but I don't think it is spring loaded.
Such things existed in the dim past, but they were always broken in some way and replaced by correctly working pots.
In my (limited) experience, pots used for position sensing usually fail because they are not mounted properly and allowed to travel past the proper limits.
If I wanted a resistance switching thingy I would've asked for a resistance switching thingy. Though sorry if my post wasn't concise.
I've seen it done mechanically with a rack and pinion arrangement.
And with a pulley wheel cord and spring.
Also many modern vehicles have this sort off arrangement for the accelerator pedal - but it aint cheap (£250 when my Merc throttle pedal failed)
If you dont need precision would a force sensitive resistor work?
Hi, @anon77129126
Can you tell us the application you are wanting to use such a potentiometer.
Thanks.. Tom... 
If you are playing with Microcontrollers, why do not go for a encoder that has already the built in push button? Can it be an option?
@johnerrington Could you recommend a good pot to do rack and pinion with. I do need precision.
@TomGeorge Electric go kart. Not sure if I'm going to build it but I'm researching. I want to mount the throttle as a paddle that the user can pull mounted behind the steering wheel (same with the brakes, which I will explain in my project status thread).
@juannavarro No. See my reply to cedarlakeinstruments.
Seems to me you need to work out the mechanical linkage. How will you control the throttle while you are steering? That doesnt lend itself to precision.
You could use a lever attached to the pot - you dont need to use the whole 270 degrees (or 10 turns!)
The system would be similar to bicycle braking.
EDIT - Or trigger shifting for that matter. Pull a lever, thing happens. The steering wheel wouldn't have that much rotation so it wouldn't be too awkward.
Hi.
Steering wheel paddles are usually just switches, as the action while your hands are on the wheel are limited and hard to be precise.
Put the paddle in the shaft of a potentiometer, moving the paddle turns the pot shaft, you will not have much range of movement from a standard pot (270 degrees from max to minimum) but you can scale/offset that in software.
A pot on the paddle shaft would take up less space.
A rotary encoder could also be used, but you would need to have suitable resolution to get the response your would be looking for and an a associated switch to detect zero throttle.
Can you please tell us your electronics, programming, arduino, hardware experience?
Thanks.. Tom...
You want a resume of my making ability? Sure.
I'm 14. I'm capable of reading and applying datasheets, designing PCBs in KiCAD, using OnShape (online CAD), soldering, 3D printing, and using semi-complex tools. I have little experience with programming outside of Arduino and even at that I'd say I'm not too good at it. I am more of a hardware guy, and my best abilities are mostly troubleshooting and generally (I think) being somewhat okay at the design process/coming up with project ideas. My weaknesses are coding (as I mentioned), mechanical engineering, and keeping the magic smoke in my ICs. I'm also not great at raw electrical engineering. I mostly rely on modules.
My biggest strength by far is the ability to capitalize letters at the beginning of sentences and use full words instead of acronyms, even at this age. 
I have owned a go kart in the past and quite enjoyed it, but I liked the idea of a pull paddle better for this new (custom framed) design. The idea came from a sci-fi fiction book I am writing as a side project, when I had to find a way to control a starship in three dimensions quickly and ergonomically.
EDIT - To comment on the actual content of your post, what would I do for a spring return? Do spring return pots exist? Or would I have to build something in with like a pen spring?
EDIT - I have a rotary encoder on hand but the resolution for this would be like 15.
EDIT - Also despite the fact that I said I have limited software experience, it really should be easy for this project.
Hi,
Thanks for the info.
On the paddle all you need is for it to press against a coil spring as you advance the paddle/speed. The spring will push the paddle and the pot shaft beck to initial position.
I can see you needing to make a benchtop prototype to research the actual mechanics.
There are encoders with greater resolution, including magnetic touchless types.
This one has 4096 steps per 360 degrees.
I'm not sure how much angle movement you require.
Tom..
As you are trying to convert a movement of a lever to a voltage you dont need to restricty yourself to using a pot. Have you considered using a ratiometric hall effect sensor and magnet?
eg ss49E - as used for electric bike throttle control
Look into using an encoder for this purpose: Encoder - Arduino Reference
The knobs on automobile radios and other electronics use these sorts of encoders to adjust volume and select menus. They feel like potentiometers with a pushbutton and could be coded to vary an output variable as you describe.
@TomGeorge Really not much movement needed. 20 degrees maybe?
@johnerrington I've got a 49E that I've tested. I don't like them because they aren't very sensitive.
@DaveX the KY-040 module isn't going to provide enough resolution.
So now the question becomes how to do the spring return.
You can use two at right angles or in opposition to increase sensitivity, and you can add a simple op amp circuit to increase it further; and use strong magnets in close proximity to the sensors.
Magnetic sensors are generally preferred for automotive use over resistive or optical sensors because they are robust and not affected by dirty environments.
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