Hi,
can someone explain me or point me to some online doc on how does the tuning button on a simple fm radio works.
Is it a variable resistor so that it could be replace by an analog out from the arduino ?
ok after some more research i've found that it's a variable capacitor
Yes on older radios it's a variable capacitor. I believe that on newer radios it's some kind of digital stuff.
I took apartt a couple of those very small and cheap "auto tuning" radios, where you just push a small button to have it search for the next station, and i did not find a variable capacitor in them.
This may help you ekko..
You may also want to look at the TDA7000 which is an FM receiver on a chip. I don't have one, but it looks easy to use. I'm just learning about radios and would like to build a couple simple ones soon. I'm sure you could use the Arduino for frequency display.