Audio decoder from mobile phone (TRS)

Y

Yasserbn

New Member
I want to build a circuit that takes the audio output of the mobile phone (coming from TRS cable) as an input to control 3 or 4 relays depending on the sound frequency played on the phone.

In other words, if I played 16Khz mp3 file on the mobile phone, the circuit should switch relay #1
If I played 18Khz mp3 file on the mobile phone, the circuit should switch relay #2, and so on.

What is the recommended IC for this circuit?
I know that the output of the audio is AC 250mv Peak to Peak.

Any help?
 
i think you should use 4 filters according to the frequency u require, and then add transister as a switch at the output off your circuit,,,, but make sure your filters are of small and accurate bandwidth

HERE IS THE BASIC IDEA FOR IT
View attachment 67250
 
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Post deleted
 
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Yep DTMF was designed for reliable operating of multiple things from an audio (phone or RF) signal.

There are a few kits that have a PCB and a few relays, designed for DTMF 'phone controlled home automation stuff (like turning lights on and sprinkers on etc), so a google search would be a good idea.

Otherwise if using mobile 'phones most home automation people now use SMS type decoders, there are kits for those too but they are a bit more high tech and use microcontrollers.
 
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