Audio decoder from mobile phone (TRS)

[Yasserbn]

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?

 

[japanjot]

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

 

[alec_t]

Post deleted

 

[alec_t]

Perhaps a DTMF decoder IC as the basis?
Or this kit?
https://www.google.co.uk/url?sa=t&r...yYDoBw&usg=AFQjCNGNuUn8pfkhNOb0Ij3wABJYaHsK7A

 

[Mr RB]

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.