Hi I’m thinking of using a string on my guitar as a rheostat and using a steel slide connected to an analog pin to adjust voltage values. I’ve tried using it in a potential divider circuit but I don’t seem to be getting anywhere. I think the steel string isn’t resistive enough? If I changed the string for a length of constantan wire would that work? Or is the idea flawed from the start. Any help would be appreciated.
I dont have an answer for you but I do know 1 thing
- the resistance over that length of wire is going to be very tiny
you can make a rheostat using some paper and a heavy marking of pencil graphite, but I doubt that would stand up long with guitar strings, maybe something else to think of is connecting the frets to increasing sized resistors.
(and another idea, but totally made up out of thin air, if its an electric guitar maybe use the pickups and a half wave rectifier, to turn the ac output into a 50% pulse train and time using pulse in, again totally made up, no idea if that is even possible)
A quick check on EBAY shows this: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310090965642&rvr_id=&crlp=1_263602_263622&UA=WXF%3F&GUID=3f47bf031240a0437386b2e6ffe84c3c&itemid=310090965642&ff4=263602_263622
Blech… Ugly URL sorry
Anyway, it’s 30 FT of NICHROME restistance wire for like… $3.00.
That would do what you want, no?
Yes your problem is that the resistance change you are trying to measure is very small in comparison to the resistance in the connecting wires. Measuring small currents in small resistance is very difficult.
You could consider wiring up the frets and using the contact with the wire to detect what you want.