Trying out a fun project for the spooky season. I have the radio listed below that I would like to modify. This has been done before by someone else but I cant get in touch with them to help. From what I understand an arduino nano would be programmed to output sweeping voltage to the tuner dial. It basically tricks the radio into thinking you are turning the dial back and forth. Below is the radio and a video of one someone did make
Amazon.com: PRUNUS R-818 Retro FM Radio Bluetooth Mini Portable Wooden Old Vintage Radio Speaker, Rechargeable Battery Operated, Strong Bass Enhancement, Loud Volume, Support AUX in (Cherry) : Electronics
No. External circuitry is needed. Either a low pas filter or a DAC.
Sorry. Watching videos takes time that most helpers are not willing to spend.
I find this curious, because FM radios are typically muted when they’re off-channel between stations.
I suspect the radio ‘tuning’’ effect you’re looking for is only possible with an AM receiver.
In reality, as a prop, you might get better results with a pre-recorded MP3 soundtrack in an SD card
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Hi,
You are trying to make a ghost box, made "infamous" on paranormal ghost hunting shows on pay TV.
The guy wants to sell you one.
Can you please tell us your electronics, programming, arduino, hardware experience?
Do you know anything about FM receivers?
Do you have a DMM?
Thanks.. Tom.. 
Yep. Tuning is via a vericap diode... likely added to the existing tuning capacitor, but tuning could be completely by vericap; my guess is one is just added across the existing variable tuning cap: thus, lowering the capacitance and the tune-to frequency.
A simple RC circuit can be utilized to take the Arduino pulse-width signal and convert that to a DC potential to bias the vericap. Change the pulse width and change the vericap bias and thus the frequency.
Thread moved as requested.
Have you got the radio's schematic( I couldn't find one on Amazon) or have you looked at its internals yet? We are interested in it's tuner specifics, we can look up datasheet and see how we can mod the control signal.
But working with aux input might the more tenable solution.
Let me know what you think.
If it's a variable capacitor for tuning there is an old thread with the do's and (mainly) don't of such a modification
https://forum.arduino.cc/t/control-fm-am-radio-frequency-with-arduino/271961
They make DCO (Digitally Controlled Oscillator) chips that would communicate with your Arduino. Of course you could get an analog version and with a few chips make a triangle waveform to drive it. The easiest way would be to inject the signal.
it would appear the knob in charge of tuning has a max voltage of 1.074 and min down to 0. I believe if I were to randomize the voltage from the max-min it would mimic tuning the dial. If I add in doing this at a certain rate of speed everything should work as intended. As ive stated in the original post. That is basically what the other person did with theirs
Instead of randomising, you could just scale up from 0-1.074 . It would simulate an actual tuning ..
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