And by this I mean using one with a small LCD board for UI and then drives audio selector and a volume system.
My interest is in building something that turns my amp system on when the data projector powers up (it has a serial output that reports on what it's doing). That developed into something to control the whole custom amp system.
Switching mains power I can figure as I have access to expertise to help design that safely (I'll almost certainly use a relay). Switching audio I was thinking of a 4052. I already have a pre-amp module that uses a VCA so a simple analog level from the Arduino should work just fine.
Do you want to control your amplifier or just control the signal level entering it, (aside from turning it on)
Working with mains is always a bit dangerous, someone posted about using remote control mains sockets the other day. I have used these with a cheap 433mhz transmitter module $1 and that worked for me, to turn some devices on and off.
Re: VCA
There is a device called a digital potentiometer, its a chip where you can control its resistance. You use one of those to control you existing VCA
so overall this is very do-able, but you need to spec it out in a bit more detail for anyone to be able to give a detailed response
rogerClark:
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so overall this is very do-able, but you need to spec it out in a bit more detail for anyone to be able to give a detailed response
I was only after a general response (many thanks!).
The VCA chip I already have in use is part of a pre-amp module I built years ago as a kit (it's actually a Dolby Surround decoder). So I have a circuit diagram for how it's used. But a digital pot is a good idea. I hadn't thought of that!
The amp I was intending to use I also built from a kit, and was far from the first, so I've worked with mains-level circuits before. But I would only need to turn the amp modules themselves just on or off. All other controls would be on or before the pre-amp.
My project is used in the car, but it does most of what you're talking about.
I'm using an Arduino Nano to control everything, but the volume control is handled by a PGA2311 attenuator chip. It's very easy to control with the Arduino via SPI.
Audio switching is done using very high quality Omron G6K 5v relays (driven by a ULN2803). I'm using the latching versions so once switched, you don't need to power the coils. You just give a reverse polarity pulse to fire them back the other way when required.