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Topic: audio input and volume (Read 1 time) previous topic - next topic


Hey Guys,

Im absolutely new to hardware, and want to get started on some projects to pass the time and make life more fun!!
In my house at the moment ive got 2 dstv decoders, a radio and cd player in my "server cabinet" and I can connect any ONE of them to the speakers in the house (50-80w car 6inch speakers) ive got like 2 in every room.
So what I want to do is give every room a arduino,remote (IR) and make every room able to choose the input and volumeā€¦..
Ive read up on audio and I am completely confused, I have no clue what preamps ect does? For the inputs can I use 4 relays? Open current selected input and just close desired input relay? how can I reduce and increase volume?
Sorry for the stupid questions but I really need some guidance :)



It sounds like you already have a distributed audio system, so maybe a wi-fi type connection and control would be better than infrared.  If your receiver/amplifier doesn't have any type of remote control capability, there is no way sans modifying the receiver to control the volume remotely short of using a stepper motor to physically turn the control itself.


Apr 09, 2014, 08:51 pm Last Edit: Apr 09, 2014, 08:59 pm by DVDdoug Reason: 1
What's powering the speakers? Typically you'd already have a receiver (or preamp or integrated amp) with an input-selection switch.*   And, hopefully you have an amp for each room, or a 70.7V constant-voltage system?   (Connecting a bunch of speakers in parallel lowers the impedance and that can damage your amplifier, and you need separate amps if each room can select different audio sources..)

For the inputs can I use 4 relays?
Yes.  A double-pole double throw relay for each input.  Or, you could also use a digitally controlled Analog Switches.    (If you are going to build this thing, I'd add a couple extra inputs for unknown future requirements. ;) )

how can I reduce and increase volume?
A Digital Pots, assuming you are controlling line-level signals (not the speaker outputs).  A digital pot won't "increase" the volume, but you shouldn't an additional gain stage.

Im absolutely new to hardware, and want to get started
I suggest you tackle one part at a time.   I have a feeling the IR remote is the most difficult part and I'd start by turning on & off an LED (and then maybe dimming the LED).

You can also build & test the relay switching separately, and the digital-pot volume control separately.   There are at least 3 different kinds of digital pot.   I've never used a digital pot, but I believe there is a type that you simply feed-in an up-down pulse and that seems like the simplest to interface & "program".

* It's OK to connect more than one input together.. So for example, you can use Y-Adapters (splitters) to connect the CD player output into 4 amplifiers/receivers.   However, it's NOT OK to connect multiple outputs together, so you can't connect the CD-player output to the radio output.    For that you need relays to select one output at a time, or a mixer to mix the audio signals.

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