Audio Switching?

[MAHABA]

Hi everybody,,

How could I activate (switch) a relay by an audio signal received from a source like cd-player??

The relay should switch on, when audio (music) turned on.

thank you

 

[Harald Kapp]

Amplify the signal, rectify it (diode), add a low pass filter to smooth the signal, add a schmitt-trigger circuit and set the threshold of the schmitt-trigger such that it will trigger at the signal level you want. From the output of the schmitt trigger control the relay.

Harald

 

[MAHABA]

Hi Harald Kapp,,
You significantly prove that your are a Senior Member..
thanx a lot..

Could someone provide a schematic diagram (with resistor values) of how the circuit will look like?

 

[Harald Kapp]

I found this:
http://www.google.de/imgres?q=voice...&ndsp=22&ved=1t:429,r:0,s:0,i:66&tx=83&ty=127

Replace the microphone by a line input by adding large series resistor to attenuate the signal.
Or Google "voice activated switch".

Harald

 

[MAHABA]

Hi Harald,,
thanx agin for your help ^_^

I am waiting for ideas from other members,,,

 

[gorgon]

You don't tell if the relay should switch OFF when the signal disappear, or stay on?

TOK

 

[(*steve*)]

I am waiting for ideas from other members,,,

Unless you have a problem with the information Harald gave you, or until you give us more information describing why his answer is inappropriate, you are unlikely to get further answers.

 

[MAHABA]

You don't tell if the relay should switch OFF when the signal disappear, or stay on?

TOK

gorgon,, the relay should stay on,,
thank you for your nice observation..

 

[MAHABA]

Unless you have a problem with the information Harald gave you, or until you give us more information describing why his answer is inappropriate, you are unlikely to get further answers.

What I need is a schematic diagram of what Harald said>>

He said "Amplify the signal, rectify it (diode), add a low pass filter to smooth the signal, add a schmitt-trigger circuit and set the threshold of the schmitt-trigger such that it will trigger at the signal level you want. From the output of the schmitt trigger control the relay."

Also, new idea of simpler circuit is appreciated with circuit diagram..

thanx guys

 

[CocaCola]

Also, new idea of simpler circuit is appreciated with circuit diagram..

Have you tried a Google search?

Click It ~ LMGTFY

 

[(*steve*)]

Click It ~ LMGTFY

Add the word "schematic", and click on images after you do the search.

 

[Harald Kapp]

This, http://www.google.de/imgres?q=voice...&ndsp=22&ved=1t:429,r:0,s:0,i:66&tx=83&ty=127 is a very simple circuit, as i have posted .

Harald