remote controlled speaker volume

Hi,

I have played with some PIC microcontrollers and wanted to do this small project. I have like 7 speakers and i wanted to make their volume to be controlled using IR. So the remote can have 3 buttons (Up, Down, mute).

The question is, how to actually control the volume of the speaker so that the quality of sound is not reduced. Any suggestions?

EDIT: Also how can i limit the range that when pointing remote to one speaker should only change volume for that particular speaker and not others near by

haxan said:

how can i limit the range that when pointing remote to one speaker should only change volume for that particular speaker and not others near by

Click to expand...

1. Your IR LED must have a very small angle of output. I think you will have problems talking to only one speaker.
2. Use address (speaker-4, up, up ,up, speaker-1, down)

yes i believe addressing is one of the solutions. I wanted to keep the system and remote simple. Thanks for the feedback though.

Any thoughts on how to actually control the volume of the speaker without quality reduction?

haxan said:

Any thoughts on how to actually control the volume of the speaker without quality reduction?

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You can use a digital potentiometer IC, or a programmable attenuator. Both can provide a similar function and I believe they shouldn't affect the quality too much; refer to datasheet to make sure.

haxan said:

yes i believe addressing is one of the solutions. I wanted to keep the system and remote simple. Thanks for the feedback though.

Any thoughts on how to actually control the volume of the speaker without quality reduction?

Click to expand...

You don't - you control the volume in the amplifier - but you need to be more specific about exactly what you're got, and exactly what you want to do.

Having an amplifier in each speaker, and all controlled by the same codes, isn't going to work.

Nigel Goodwin said:

You don't - you control the volume in the amplifier - but you need to be more specific about exactly what you're got, and exactly what you want to do.

Having an amplifier in each speaker, and all controlled by the same codes, isn't going to work.

Click to expand...

Well i have an amplifier hooked with all the speakers simultaneously. I just want to be able to control individual speaker's volume using one universal IR remote. It should work like this:

I point my remote to a speaker, reduce its volume (while keeping the others at same level)

Do i make any sense ?

haxan said:

Well i have an amplifier hooked with all the speakers simultaneously. I just want to be able to control individual speaker's volume using one universal IR remote. It should work like this:

Click to expand...

You need a separate amplifier for each speaker, volume is controlled at a low level inside the amplifier.

I point my remote to a speaker, reduce its volume (while keeping the others at same level)

Do i make any sense ?

Click to expand...

IR remotes aren't that precise - and would be pretty useless if they were. The signal is quite wide, and bounces round the room.

You need a separate amplifier for each speaker with electronic control of their volume. You then have an IR red receiver on each amplifier, and a PIC (or similar) to decode the IR signals and control the volume device (digital potentiometer or whatever).

You then have a remote control with seven different up/down buttons, with each pair controlling one specific amplifier (by sending different codes).

You can use an IC such as PGA2320 to control the volume with very little (if any) quality reduction if the circuit layout is designed correctly.

You will need 1 IC for each pair of channels. You will have to go:
Source -> Your volume control -> Amplifiers

IMO you are better off having one unit for the whole thing, and a seperate button on your remote for each speakers volume.

The problem with having so many amplifiers is that it will be hard if i want to control the master volume.

In my initial project design i thought i could control the master volume using a powerful amplifier and percent of that volume be used on the speaker.

For example:

If the amplifier volume is set to 50% output, and i have a speaker on 50%, the actual output will be 25%. (i hope you get the point)

So if i want to reduce the master volume, all speaker are affected.

Is their any other proposal to make this project work somehow?

Consider this, there are 7 speaker in seven different rooms of a house. I want to use one source for all of them and keep each speakers volume a percent of the amplifiers output. How would you do it?

I have done addressing system before using IR. I can create four addresses and then assign each speaker an alternate address if its close by to other speaker. The remote can have like 4 buttons (2 for volume up/down 2 for address selection up/down)

I have never played with sound systems before so thats why i am little uncertain of how the project can be done.

If nothing works then the final solution can be :

Source -> Amplifier -> Volume control system -> amplifier -> Speaker

But i want to keep the system simple if possible

Any suggestions?

haxan said:

How would you do it?

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You might start, like many of us do, with a little research. I would suggest searching for "chip amp" or "gainclone amp" or check out the DIY-Audio forums.

I suspect an LM3780 (60w stereo or 120w mono) chip amp, a PGA2310 or PGA2320 stereo preamp (plus microcontroller) for each speaker might work pretty well...

Regards, Mike

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haxan said:

The problem with having so many amplifiers is that it will be hard if i want to control the master volume.

In my initial project design i thought i could control the master volume using a powerful amplifier and percent of that volume be used on the speaker.

For example:

If the amplifier volume is set to 50% output, and i have a speaker on 50%, the actual output will be 25%. (i hope you get the point)

Click to expand...

It is trivial for a microcontroller to do this. It is basic maths. Microcontrollers are pretty good at maths.

haxan said:

If the amplifier volume is set to 50% output, and i have a speaker on 50%, the actual output will be 25%. (i hope you get the point)
So if i want to reduce the master volume, all speaker are affected.
Is their any other proposal to make this project work somehow?

Click to expand...

So the main audio source is fed through the master volume control; the resulting output is fed into the input of each speaker amplifier, each having its own dedicated volume control.

dougy83 said:

So the main audio source is fed through the master volume control; the resulting output is fed into the input of each speaker amplifier, each having its own dedicated volume control.

Click to expand...

That's how I understand what he wants - but he needs an amplifier and remote control circuit per speaker - and only a preamp at the master control.

Nigel Goodwin said:

That's how I understand what he wants - but he needs an amplifier and remote control circuit per speaker - and only a preamp at the master control.

Click to expand...

Any suggestion on how to make a very simple amplifier with very few parts? (i have heard that playing with components for audio conversions is very tricky as any small glitch can translate into the audio signal) I have found this circuit but it seems full of components (https://www.instructables.com/id/Make-a-Simple-Audio-Amplifier/

Is there a single IC that can be used for amplification but with not a complex network of components?

Search for "Gadget Freak Case #192: The Ultimate Wireless Volume Control"

ronsimpson said:

Search for "Gadget Freak Case #192: The Ultimate Wireless Volume Control"

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Thanks ronsimpson. Thats almost exactly what i want to make. There is just one problem, i dont have the dallas digital pots available in my local market
Also the guy uses RF remote where as i want to use IR but i guess i will work on that.

You might consider using one of those universal TV remote controls as the source of the IR signals. If you decide that keys 1 and 4 (assuming a phone keyboard layout) are up and down for speaker A and 2 and 5 are up and down for speaker B etc then all you have to do is figure out what code it sends for each key and program your PIC to respond appropriately.

I did something similar years ago - but only for one amplifier in addition to the normal TV amp. Unfortunately I have not kept any of the details. I remember getting the remote control to think that my device was a TV that had a simple IR coding, but I can't remember how I chose the TV. I may have set up my PC to pick up and store the code sequence so I could look at it on the screen - fairly trivial in the days of the PC parallel port

Thanks Robin2. You have a good idea. I actually don't have any problem with remotes. I made my own remote for a project recently using sony's SIRC protocol. I can assign a different code of my own to any number of keys i want to use. But for testing, i might use your method. Once the testing will be complete, i can make my own remote controller with only 5 buttons [Up , Down, Address Selection Up, Address Selection Down, Mute ]

Address selection can embed a small bit to either start or end of the SIRC signal sequence. I can then decode it according to the address of the PIC.

I haven't done any parallel port programming but have played with serial port a few times. Too bad we don't see them in any new computers now.

I cannot seem to find any good analogue amplifier circuit with digital volume control (digital pot). All i can find are complete products from china which can only be ordered in bulks.

Can anyone point me in the right direction please ?

I want a small amplifier circuit which can amplify a normal house hold computer speaker. The circuit mentioned by ronsimpson is not loading up.

You do not need amps for every speaker. You CAN use a speaker attenuator. It is also known as a "L" pad. Its a high power potentiometer.
You can switch high power resistors in series with your speakers with a remote to attenuate your speaker volume.
google "speaker attenuator" to get started.
Andy