Can anyone explain how to (or where to find instructions) build an
accurate linear slide potentiometer of 100k, 150k or 1M ohm? I am
looking to make one with a physical length would be from 2" to 10". I
have seen little exercises where you can draw a pencil line on paper
and connect electrodes to it, and it acts as a resistor, so I am
thinking that building a slide pot might be possible with the right
materials. Any info appreciated...
how about a ~ 3 " cross diameter shelve mounted on a shaft of a pot?
the shelve would have a mine steel or strong fishing line wrapped out
it that connects on both ends of the linear rode movement so that it
will turn the pot..
You're asking for an 8 inch travel , 8 / Pi = ~2.5 inch in width..
add a little for the fact that the pot does not do 360 degree's unless
you get a rotary pot
then there's the option of connecting a multiturn pot on the end of
the drive mechanics that is doing the traversing, Acme lead screw or
ball nut screw for example.
of course, You can do what I did once, it wasn't a linear track slide
but it could apply to you..
I got some large carpenter pencils and took the lead out or should I
say, more like carbon .. I suppose you can buy the stuff also..
I took an old screw driver handle and stuck it in a baby food jar with
turpentine and a rag wrapped around the entry point so that it wouldn't
evaporate.
After some time the old handle dissolve away from the screw driver
making a nice pliable plastic putty more or less..
Then I mixed the ground carbon power that I made into it, using a
popsicle stick as the mixer..
when you get ready to apply it in a linear track in your case for
example, poor it on and lay wax paper on top where the wiper will be.
The wax should allow it to peal away leaving a rather smooth surface
that is conductive..
p.s.
Make sure you have your end connections in the track before poring
this and the mix on the carbon has to be strong verses the potted
material you decide to use.
Btw, the dissolving of existing plastics is an old trick body shop
guys use if they are repairing a small damaged area of the plastic
interior of your car. They cut off small pieces of the same plastic so
that the color and mix will match and then use the rest of the other
tools they have for matcning up the textures and so on. I don't remember
the chemicals they used for this. I know it wasn't turpentine but
something that does the same job
