I want to turn my speakers off using a remote to controll the voltage/current to them using an IR remote.
I've got the IR part set up and i can get it to switch a relay but i want it to be silent so i'm using an optocoupler.
the optocouplers transistor side can't take the high voltage of my speakers so i want to connect the transistor output to the input of the gate of an irf840, to turn on and off when i switch the LED side of the optocoupler.
how do i go about doin this?
thanks for the help
the optocouplers transistor side can't take the high voltage of my speakers so i want to connect the transistor output to the input of the gate of an irf840, to turn on and off when i switch the LED side of the optocoupler.
how do i go about doin this?
It's not going to be very easy. Speaker level sound is a AC voltage and most optoisolator/mosfet transistor circuits are set up to switch a DC voltage on and off. I think relay is a good simple solution all in all compared to what a solid state circuit would require to switch a higher level AC audio signal.
Lefty
You might try a standard power transistor like the ones at Radio Shack.
could i cut the live wire comin from the mains, attach one side to the drain and the other side to the source of the irf840 and have a voltage going to the gate of the mosfet to switch the connection to the two wires?
That's what i was thinking i could do, and the output of the transistor from the optocoupler would switch the gate voltage.
Im not sure how i'd connect a voltage to the transistor side of the optocoupler.
When you start mentioning mains power and the surmises mentioned, you give me the heebie-jeebies!
The best plan if you are switching mains power to the amplifier would be to get a Solid-State Relay (SSR) which is basically a high-power optocoupler that switches mains voltage on the load side from a 5-32v input that drives an LED optical switch. Your Arduino can drive it directly and it can be safely wired so you don't zap yourself to oblivion.
The way I would do it would be to control the audio input to the amplifier (much lower voltages involved). There are ICs made to do this like the http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=NJM2521D-ND. I actually did it way back with some jfet transistors, but if you weren't careful it could add distortion to your line signal going into the amp.
PS. This circuit is really darn close to what I was using with the JFET transistors mentioned above. It will switch line audio with a 5-15 volt input Audio Switch Notes