Arduino Forum

Using Arduino => General Electronics => Topic started by: SymonCarpenter on Jun 02, 2015, 10:06 pm

Title: reading logarithmic values on linear potentiometer
Post by: SymonCarpenter on Jun 02, 2015, 10:06 pm
Hey!

I'm trying to read my new slide potentiometer

data sheet:
http://files.voelkner.de/675000-699999/675480-da-01-en-60MM_DUAL_SCHIEBEPOTI_PS60M_10K_20_.pdf

(without LED)

but unfortunately I'm getting logarithmic values.
I checked with the multimeter and it gives me 5k at center position as it should, but on the seriell monitor I get 16 at the same position where it should be around 500-512, shouldn't it? :o

thanks in advance for your help!
Title: Re: reading logarithmic values on linear potentiometer
Post by: DrAzzy on Jun 02, 2015, 10:17 pm
If you're getting 5k resistance at middle it's not a log pot; I suspect it's wired wrong.
Title: Re: reading logarithmic values on linear potentiometer
Post by: dlloyd on Jun 03, 2015, 02:57 am
I'm sure all could be explained knowing your pot's part#, how its connected and your code.
Title: Re: reading logarithmic values on linear potentiometer
Post by: Paul_KD7HB on Jun 03, 2015, 04:43 am
The data sheet you referenced tells you there are three different resistance tapers available and they are A, B, and C. Only B is linear taper. What model number do you have?

Paul
Title: Re: reading logarithmic values on linear potentiometer
Post by: Wawa on Jun 03, 2015, 05:00 am
I checked with the multimeter and it gives me 5k at center position as it should, but on the seriell monitor I get 16 at the same position where it should be around 500-512, shouldn't it? :o
Did you connect all three pins. +5volt, ground, and taper.

You could get low values if the 5volt connection is missing.
Leo..
Title: Re: reading logarithmic values on linear potentiometer
Post by: SymonCarpenter on Jun 03, 2015, 05:56 pm
thank you very much for your help!

Turns out I confused the taper and the ground pin.


feeling a little bit stupid now
Title: Re: reading logarithmic values on linear potentiometer
Post by: JohnLincoln on Jun 03, 2015, 09:26 pm
Don't feel stupid, we all make mistakes, and have to learn by them.
I'm glad you have got it sorted out.