For a small summer project I obtained a rotary switch at a car scrap-yard. Or so I thought.
The thing was originally for adjusting the height of the beam from the drivers seat and has 11 distinct positions. There where only four terminals on the back so I figured that it was some kind of rheostat, pot-as-voltage-divider or something like that.
I tried to measure with the DVM on the different terminals, but everything was rock steady.
So I opened it up, and it turns out that two of the terminals are for a small bulb to light up symbols on the panel.
The two other go to a coil. Inside this coil is what looks like a permanent magnet or a ferrite cylinder. When Turning the knob on the thing this cylinder it moved in or out of the coil.
How does this work? (I suppose it was used to read out the L of it in some kind of way, but how?)
Is there any realistic chance of hooking this up to
an AVR to read the positions (through eg the ADC)?
I always tell you that I am primarily a software person, and this is outside of what I can manage electrically.
Background: The Old Volvo has an interval wiper with only one setting, and it is driving me mad. You either have too much water on the winshield, or you have the screeeeching of wipers on a too dry shield. Only alternative is to "tap" the wiper lever by hand, which also sucks.
I thought I'd arrange something a bit more adjustable with an AVR and some surrounding stuff. I got the thing out of another old Volvo, so it fits perfectly in a free place on the dash-board, both spatially and aestethically. I'd love to be able to use it with as little modification as possible.