What is this called? Or does it exist? A linear encoder as a slider button - Page 1
Forum section: electronics / beginners

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: December 01, 2019, 12:16:13 pm
content: Hi,I am looking for something like a linear potentiometer like they are used in DJ mixing desks. However, as a linear encoder. I know linear encoders exist for rail systems but does it exist for manual input?Is there a name for it? Or does it exist at all?

author: Rerouter
author_rank: Super Contributor
timestamp: December 01, 2019, 12:19:44 pm
content: I would assume something very similar to electronic verniers, using capacitor sensor arrays to determine the absolute position.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 01, 2019, 12:21:26 pm
content: A digital caliper would be a good candidate for a very precise linear encoder, and it has manual input.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: December 01, 2019, 12:30:14 pm
content: Yes, that is true. But I am looking for something in a ready to use package. Similar to this:I don't really want to bodge something together from an old Caliper.

author: Rerouter
author_rank: Super Contributor
timestamp: December 01, 2019, 12:40:50 pm
content: you don't have to use an old vernier, they sell them as kits that are expected to bolt on to CNC axis's, just struggling to find the correct search term right now.

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2019, 12:45:54 pm
content: You don't say what resolution you need, or whether it's got to be relative or absolute (that would rule out most calipers anyway).For absolute, the easiest way would be to use the existing resistive track and an ADC or bunch of comparators. Actually, the method used for a lot of multiple button applications is a stair-stepping DAC output and a comparator that flips when the appropriate resistance ratio is reached.

author: IDEngineer
author_rank: Super Contributor
timestamp: December 01, 2019, 05:02:33 pm
content: Not sure what you're asking for... linear position sensing is available using almost any discipline imaginable. Obviously linear pots do it resistively, LVDT's do it with inductance (and there are other inductive means too), there are linear position sensor based on capacitance, etc.By "linear encoder" do you mean something with an inherentlydigitaloutput, as opposed to analog? If that's what you meant, as noted by others you can derive that by A/Ding one of the aforementioned linear sensors. That would give you total control over number of bits, dynamic range, scaling, curve shaping, etc.As you noted, there are industrial linear encoders but they're not "something in a ready to use package" for direct human input.No matter what output data format you're seeking, your best and easiest solution for human input is likely going to be using something designed for human input in a "ready to use package" - which means a linear pot driving an A/D input through a buffer. Seriously, that's about as simple as it's going to get, both mechanically and electronically.Hope this helps!

author: ebclr
author_rank: Super Contributor
timestamp: December 01, 2019, 05:07:36 pm
content: https://www.asm-sensor.com/en/posichron-magnetostriktive-sensoren.html

author: ebclr
author_rank: Super Contributor
timestamp: December 01, 2019, 05:08:57 pm
content: You can also do on the capacitive like thishttps://www.waveshare.com/capacitive-touch-keypad.htmAlso, the thing you talked about is a slider potentiometerhttps://www.ebay.com/i/221804983826?chn=ps&dispctrl=1

author: IDEngineer
author_rank: Super Contributor
timestamp: December 01, 2019, 05:27:57 pm
content: Yes, lots of DIY options but the OP specifically said he didn't want to "bodge together" something, he wanted an off the shelf solution. AND one that accommodated direct human input. With those two requirements, a linear pot into an A/D made sense to me.

author: tooki
author_rank: Super Contributor
timestamp: December 01, 2019, 06:51:48 pm
content: Quote from: Blitzschnitzel on December 01, 2019, 12:16:13 pmI mean... what’s the application exactly? Within the scope of human interface devices, it’s unlikely you need digital caliper-level precision (which is what industrial linear encoders exist for). Rotary encoders exist to enable relative movement detection (i.e. endless rotation), which is impossible with a linear encoder. Otherwise, you just use a potentiometer.And so absent additional information, I completely agree with the suggestion to use a linear potentiometer whose value you read with an ADC.