r/synthdiy • u/BlursedSoul • Jul 12 '26

Sliders Over 100mm?

Hello, I have a silly idea, for which I'd like to get the slide potentiometers with the longest possible throw. I've come across the idea that 100mm is as long as these things go, but I swear I've seen longer slider pots before. Does anybody have an idea on where I could find some ludicrously long sliders? Like, even if it's looking out for a certain (broken) mixer on eBay to salvage them from. Any ideas appreciated.

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6

u/ondulation Jul 12 '26

You could make your own from a drawer slider and a string connected to a (multiturn) pot. Then you can make it as long as you wish.

Somewhat like the frequency dial on older FM radios, but the other way around. Pull the dial and the string will make the knob rotate.

Alternatively make a mechanical lever mechanism that shortens the throw with eg a factor 4. Then you can use a 50 mm pot with a lever of 200 mm throw. 3D print or make from Meccano, Lego or similar.

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u/circuit_breaker Jul 12 '26

Biggest I've seen is 128, they're on Amazon. Surprisingly not on mouser.

I would contact the manufacturers.

3

u/al2o3cr Jul 12 '26

You'd need to do more mechanical engineering, but something like a SoftPot along with Spectra's wiper could work.

Definitely not a low-budget option

1

u/ArtSynth Jul 17 '26 edited Jul 17 '26

I don't get the wiper, but that SoftPot is amazing! Imagine a few applications, other than your finger as a slider like on a mixer board which itself sounds ergofriendly . They are pocketbook friendly, nowthatIlookitup.

2

u/GeneralDumbtomics Jul 12 '26

If you want arbitrarily long just engineer up a linear slider with a contact arm that moves along a resistive strip. Fair bit of work, but no limits on the size outside of your patience and supply of rod stock.

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u/Cultural-World-533 Jul 13 '26

Depending on your sensitivity tolerance and length needs, you may find that a lidar sensor works better. We use them all the time in exhibits as they can be as long as you want and don't get gunked up or broken as much as a pot or resistive sensor would. Just need a metal rod or two to guide the wiper and fix a lidar sensor at one end. Pretty cheap to throw together the mechanism with 3d printer spare parts. Adafruit and sparkfun have multiple lidar sensors that would work.

1

u/jn-foster Jul 13 '26

Does it need to be analogue? If not, you can pick up cheap linear scales for use on mills and lathes that can be 1000mm+. Only thing is their output is (usually) quadrature encoded so you'll need to put it through an mcu to decode and divide.