Go Down

Topic: please help with linear potentiometer.. (Read 984 times) previous topic - next topic

twirap

i really needed a linear potentiometer so i went out, bought a toy n took it apart....got the toy cheap for 3$ but it has 6 linear pots....i looked all over the internet the only info i found were how to hook rotatory pots to arduino for servos but i couldnt find anything on linear pot's hook up....no info on google about the different terminals either....can someone please help I am confused....

retrolefty

The best way to check out the terminals on any pot is to use the ohm-meter function of your DMM. If you don't own a meter that should be your very next purchase before any other electronic item, it's essential for working with an arduino project.

Anyway with a meter if you test with a meter, two of the terminals will read a constant ohm value between them no matter where you move the slider. The third terminal will read a variable resistance between itself and either of the other two terminals. Usage is normally to wire one of the 'end' terminals to arduino ground, the other 'end' terminal to +5vdc and then the wiper terminal to a analog input pin.

Here is a picture of a linear slide pot. Note the two 'end' terminals and one next to the left end terminal. In this example the end terminal on the left would be grounded, the far end terminal to +5vdc and the 'wiper' terminal is the analog output voltage to be wired to a arduino analog input pin.
http://www.allelectronics.com/make-a-store/item/SLP-50KS/50K-LINEAR-SLIDE-POT-CENTER-DETENT/1.html

Is that helpful? If not if you could post a picture or a link to the datasheet we can try some more to help you figure it out.

Lefty

twirap

oh this one is kind of different......the linear pot I took out of the toy has 2 end terminals on one side, 2 terminals on the other side, and 2 terminals in the center 1 inch spaced...

retrolefty


oh this one is kind of different......the linear pot I took out of the toy has 2 end terminals on one side, 2 terminals on the other side, and 2 terminals in the center 1 inch spaced...


Some time they add extra terminals just for added mechanical strength when mounted to a board. The 'extra' pins may be not connected electrically to anything, or they might be duplicates of the basic three terminals required for a pot.
Need a picture or better yet a link to a datasheet.

Lefty


twirap

ahhh im not sure what to do :S i can provide you pictures in a sec, cant get u data sheet as i took these out of a toy so they have no name or any rating or anything on them....

retrolefty


ahhh im not sure what to do :S i can provide you pictures in a sec, cant get u data sheet as i took these out of a toy so they have no name or any rating or anything on them....


Well in my first post I talked about using a ohm meter to figure out the terminal connections. Do you have access to a meter?

Lefty

Magician

What kind of toy?
And what pot's suppose to regulate in the toy?

twirap

i have my dad's meter, dont know how to use it its brown has different stuff in it ill figure it out.....it was some toy dont know what it is but the point is that the POT was on a PCB right beside another POT, both linear pots and they were touching each other so side by side...both pot's did volume control but different volumes....This toy is some kind of dj music maker so it has those 2 discs and control panel....anyhow thats that...I am guessing that they have those extra pins because these 2 pots were connected to each other on the PCB..

Magician

My guess this pot "stereo" - double version or ton-compensated, it would explain additional taps.
You can try to search yourself, may be some images could get you idea.
http://www.allelectronics.com/make-a-store/search/pot/results/2.html

Why not to try, basic function is the same for different kind of pots, take along one side two ends pin and one in the middle. Two ends will go to +5 and ground.

mem


...both pot's did volume control but different volumes....This toy is some kind of dj music maker so it has those 2 discs and control panel...


Most pots used for controlling audio volume are not linear.  If you have the meter working you can check this by centering the pot and checking that the resistance from the wiper pin to each of the end pins is around the same value.


Go Up