Lubricants and Linear Potentiometers

[scott_alexsk]

Hello,

I have a potentiometer which I am using to measure the length change of a wire. The friction of the pot has been a real headache to me, and I am trying to figure out a way to decrease the friction( in both directions, I have already tried using counterbalances, and it just takes too long to shift them around w/ the number of cycles I am doing). I have already destroyed one pot by using wd40, so does anyone have any cheap ideas to decrease the friction of this thing(I know about LVDTs but there are pretty pricey to my knowledge). If you want to see an image of it, google "Phidget slider 60", and you will see one.

Thanks,
-Scott

 

[FredGarvin]

Have you tried a simple string pot? Without knowing the degree of inaccuracy you are willing to tolerate, it's tough to make suggestions.

http://www.dataq.com/applicat/articles/stringpot.htm

http://www.me-us.com/draw-wire/

 

[scott_alexsk]

Well, the resolution I need is at a minimum 5/1000 of an inch (which is what I currently have). The problem with using the string pots is that the actuating force on those is relatively large for what I am doing (I have essentially built a little tensile machine). Currently the actuating force of my linear pot is about 0.5 Newtons, and that is too much. The string pots, b/c of the spring appear to not get close to that let alone lower.

-scott