SoftPot Membrane Potentiometer - 500mm

These are very thin variable potentiometers. By pressing down on various parts of the strip, the resistance linearly changes from 100Ohms to 10,000Ohms allowing the user to very accurately calculate the relative position on the strip. Can be used as an accurate positional indicator for CNC head positioning, variable user input (volume level input for example), straight user input (multiple button areas translate to given resistance levels), and many other applications.

Unit comes with adhesive backing. Connector is 0.1" spaced and bread board friendly.

Note: These potentiometers work great with a finger, or stylus.

SoftPot Membrane Potentiometer - 500mm Product Help and Resources

SoftPot Hookup Guide

May 5, 2016

Equip your Arduino project with a sliding soft potentiometer to monitor position or adding linear control to your project.

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

1 Electrical Prototyping

Skill Level: Noob - You don't need to reference a datasheet, but you will need to know basic power requirements.
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Looking for answers to technical questions?

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  • Member #679210 / about 8 years ago / 2

    How will the potentiometer respond to a user pressing multiple points along its length?

    • Member #1505378 / about 5 years ago / 1

      If you connect it as a simple pot, there can only be one touch, but, if you connect one voltage divider on each side, you can have two touches. The problem with the two touches aproach is that the response is not linear, because one of the resistors of the divider would be fixed, though it's easy to linearize it with software. Also, I'd recommend to use a higher resolution adc, to compensate for the fact that voltage changes a lot quicker on the longer distance. A 12bit adc seems to be enough for me. There is an example of the circuit here:

  • Member #1505378 / about 5 years ago / 1

    Hello. I want to use some of this softpots on wood, actuated with fingers. My problem is that their 20mm width is a little too much for me; I need them to be 3 mm less. Does some one know, if I cut 1.5mm on each side, will it still work? What do you think? :) Thanks.

  • chipaudette / about 8 years ago / 1

    Note that these long 500mm soft pots have a resistance of ~20 kOhm, not 10 kOhm as stated in the product description. It's the shorter soft pots that have the 10 kOhm resistance.

    And for the record, my 500 mm soft pot has a resistance of about 17.5 kOhm.

  • Tony A / about 9 years ago / 1

    What is the width on these? (In inches?)

    Thanks very much, Tony

  • Member #376871 / about 12 years ago / 2

    Can anyone link me a good connector for this? I've been told soldering the connections will melt the nearby plastic.

    • xopianoi / about 11 years ago / 1

      Just spoke with SpectraSymbol, they said there is no specific mate for these, they come with solder tabs which are meant to be soldered. They do however make SoftPots with Nicomatic crimpflex housings also.

      • WitchMaster / about 11 years ago / 1

        I have been using half of a 6-pin (or 8-pin) ic socket with success, it fits snugly. Be sure not to use the ones with round holes but the cheaper ones like this:

    • exaltron / about 12 years ago / 1

      I had the same issue. I ended up doing some research and concluding that something like this would work. Don't remember why I concluded that because once I got them I realized the prongs of the softpot were spaced correctly but they aren't thick enough to be held in the female connectors. After futzing around for a while it seemed that they might slide in over the top of the connector (hard to describe without a diagram), or perhaps you're meant to use that opening to close the crimps? In any case I ended up accidentally breaking the housing apart on one of them and exposing the individual wires with the metal crimp ends. I realized I could just slide the crimps over the prongs on the softpot and close them down with pliers. Not elegant but it works.

      Oh and since I accidentally snapped off one of the softpot's prongs in the process of all this (yeah I'm that guy), I discovered that it is possible to solder directly to the softpot very carefully and quickly without killing it. YMMV..

  • Member #136878 / about 10 years ago / 1

    Would this sensor be usable for measuring water level in a tank (presumably a tank less than 500mm deep)?

  • Member #510084 / about 11 years ago / 1

    I was wondering if it's possible to trim down the sides of the ribbon to make it a bit thinner? I need to mount two of these side-by-side in a tray about 35mm wide. This means trimming the sides of the pots down. Would that just destroy them?

    • Member #604881 / about 10 years ago / 2

      Ten months late, but I can say for anyone else interested, yes. You can trip down the sides. It won't split open.

  • billblack / about 13 years ago / 1

    Has anyone used one of these? I am looking for a linear position readout for building CNC machines. The data sheet is somewhat vague about accuracy. Any idea about the accuracy/repeatability of these linear pots? Thanks for any replies.

  • esmphoto / about 13 years ago / 1

    500mm is a smidge under 20" for people like me who are to lazy to do the math.
    I believe it would be around 19.64

Customer Reviews

5 out of 5

Based on 6 ratings:

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1 of 1 found this helpful:

Works without any problems.

It is what it says, it does what it says, and the only problems that can happen are user-caused. Just be careful with it, this isn't the thing you want to break. Make sure all your connections are secure and that your strip isn't bent. Internal shorts are possible if you connect it wrong, and with high enough current you could damage the layers inside. Other than that, this has no issues.


It's exactly what we needed as an input to a modular synthesizer. We made a "modulin".

Absolutely beautiful! We love to see how our products are being used "in the wild". Thanks for sharing, and keep up the amazing work!

Great product

Worked best for me with a mega ohm resistor

Taha al ajami - amazing product

well received with protected package i would like if you can add a proper connection with the product so can be used for testing purpose or universal terminals best regards Taha

Works well

I used it as a MIDI ribbon. It has good resolution, and is sensitive. I easily get 12bits. I'd really like to get a longer one say 750mm, so that a finger touch can get a bit more resolution.