I'm not best with electronics, so need to keep things in laments terms to start.
I have a single pitch tone coming out of the headphone socket on an MP3 player. I need to change the note it produces using a dial. Is it possible to use a potentiometer (or anything else that's small and works in a circular motion) to control it's frequency? I don't need it to find individual musical notes, I just need the pitch to be variable.
It has to be simple and fit in a really small space.

Any help would be most appreciated.
Thank you.

 

Welcome to AAC. Pitch shifting is possible, but is not a simple thing to do . One way would be to use digital signal processing. Another way would be to generate a beat frequency using a tunable oscillator then filter the result to extract the sum or difference frequency. Or why not just generate a new tone independently of the headphone output?

 

whats the tone used for, can you get at the oscillator?

 

Your MP3 player is not producing a frequency which can be easily changed. It is playing back a recording that is READ ONLY data. Unless you change the data which is recorded the MP3 player will continue to reproduce the read only data that was originally recorded.

There are simple circuits which you could build that would allow you to produce a tone and control its frequency with a single pot.

 

Thanks for your replies, I'm trying to adjust the note of a looped sample played on an MP3 player, so it's not just a basic generated tone. I've been playing with ideas all morning and am starting to think that it might be best to explore software solutions rather than electronics, I'm not making a great deal of progress in that direction, but I am looking.

Thanks for your help.

 

Software is the way to go. Your MP3 player might not be able to run apps, but any smartphone makes a great tone generator. There are a bunch of free apps for this.

 

Audacity is a free audio editing software and can make some variable tones, DTMF tones, white noise and some other effects.