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Hi All,
I am doing a GSM project for my third year, and I am clueless where to begin. Please advice me. The requirements are:
A microcontroller receives a signal from a door sensor. Whenever the signal is received (i.e. door opened), the microcontroller must send a command to the GSM modem, and the GSM modem must initiate a call to some pre-defined number. When the called party answers the call, the GSM modem must play-back a voice that says something like "Door opened". So there must be an audio file stored somewhere and played-back whenever a call is answered.
So my main problem is, how do I use a GSM modem or microcontroller to play-back an audio file? Where do I store this file and retrieve it? Your advice will be highly appreciated.
"none of the GSM modems that I came across from the many different vendors have AT commands to read an audio file and play it back"
Read my post again: you would have to generate an analogue audio signal, and feed it to the modem's analogue audio input; the AT commands would just be for dialling the call...
"a chip that can store wave files"
Stop thinking about "wave files"; just think about data - digital samples of an analogue signal. There are lots of chips that can store data...
Or you could interface an SD Card or similar to your microcontroller - and read WAV files from it...