sandeepsamant
New Member
To operate a 12v 200ohm relay, with audio signal of speaker of mobile phone. Any Idea??
please suggest,......
please suggest,......
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How do you want it to operate? Will the relay latch on once sound is detected? Or do you want it to chatter on and off in sympathy with the sound?
All you need to do is get a small relay that works at the same voltage as the vibrator motor and use that to trigger whatever larger devices from that.
Typical cell phones supply around 3 volts to the motor so just look for a relay that works at that voltage.
The other option would be to run the speakers input wires through a bridge rectifier and convert the sound signal to DC and use that to power the small 3 volt relay.
Does triggering the relay have to work multiple times or just once?
It's possible to use the audio from the speaker to operate the relay, but it would be simpler and cheaper (no amplifier needed) to use the vibrator motor activation as the relay operating control, as suggested above. Would you be happy with that?
I foresee problems. Any junk or mistaken call, not just one you make deliberately, will operate the vibrator motor. And to use the speaker signal instead of the motor signal would need someone at the receiving end to answer your call before the speaker could become active, thus making the relay etc superfluous.
I just need it for a project so i don't bother for junk call. but is circuit which will hold the relay. or similar, I want to the circuit remain unconnected when I disconnect the call.