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Rotary input for a cellphone Answered

I have an idea to do a total conversion on a cellphone, including things like a steam-driven charger, etc. The issue I am running into here is if I could, I'd want to make it rotary. I saw Randofo's PIC method for making it a USB input here but I have no clue in terms of how a cellphone works, or any of the chips involved. Sadly, my knowledge is mechanical, not circuitry. Any sort of ideas are welcome... please help me progress on what I hope to be my magnum opus of steampunkerie.


. I don't think the cell system accepts pulse dialing (but not 100% sure). You could use a faux dialer that outputs tones, just don't ask me how to make it. :)

I don't think that a pulse-to-dtmf converter would work on a cellphone. The GSM system uses OOB (Out Of Band) signaling for the dialing of the number. That means that the number is sent as a packet on the signaling data channel and not in-band in the speech channel as you press the buttons. The sparkfun project is actually using a microcontroller connected to the serial port of the cell phone and is using the old Hayes ATDT -commands to dial the number as the cell phone where a modem.


10 years ago

The folks at sparkfun have an in-depth tutorial on how to hackup a rotary cellphone: