Have a look in this unlikely titled thread
https://forum.allaboutcircuits.com/threads/looking-for-circuit-designer-to-do-business-with.179315/
and my circuit in post #14.
There will probably be some other useful points in there too.

Hello @Ian0 …I have no idea about how this ‘Forum' thing works… I’ve tried to DM you , but I’ll try to contact you this way… I like your attitude and I think you might be able to assist me in a quite unique thing I’m making… It’s a guitar amp that I’ve built into a Kids Wooden Stove , he he…
I'm going to send a picture here…
What I want to achieve is putting Blue LED's around each of the hobs, and having them barely on when the Amp is powered up… and for them to brighten up ( if possible to glow more intensely when as the Audio Level increses ) the Amp has a spare 240V socket already inside…Elegance is more important than cost or circuit complexity
Thanks for looking
Dalton Napier.

 

What you are describing is similar to a color organ of years gone by. In a color organ different color incandescent lamps responded to sound frequency and amplitude. Today LEDs intensity is best controlled using what is called PWM (Pulse Width Modulation). There are a few ways to do this using a discreet components building a circuit or using a simple uC (micro-controller) circuit. What we are doing is converting the amplitude of an audio signal to a PWM output signal to drive your LEDs be they blue or whatever color you choose. The process is simple. Analog in and PWM out. Personally I would do this using a uC but it can also be done using discrete components. Any number of uC can be used but using a uC requires some minor programming. The PWM out drives a single MOSFET (Transistor Switch) which in turn drives your blue LEDs. This just being a simple overview of where you are and where you want to be.

Ron

 

Thanks for getting back to me Ron… I’m pretty good at constructing electronic things… but I’m pretty much pure trial and error when it comes to figuring out / designing unfortunately
Any help will be really appreciated
I was thinking I could get the Audio In from either the Amp Out or a little mic and somehow use that to get a bunch of LED's to intensify with the Output of the Amp?
as I said any help will be great
Thanks
Dalton Napier

 

This kit (which seems a bit dear in the UK, unfortunately) is the sort of thing. It is deigned with three channels: treble, mids, and bass. It is only designed for 4 LEDs per channel but a MOSFET could be used to make it switch a larger load.

You could take advantage of the three channels and make the flame change color with the varying spectrum, if you wanted to.

 

Hello.

On maker pro there is a thread about the color organ @Ya’akov mentioned:
https://maker.pro/forums/threads/color-organ.268022/

Bertus

 

Hello.

On maker pro there is a thread about the color organ @Ya’akov mentioned:
https://maker.pro/forums/threads/color-organ.268022/

Bertus

Thanks Bertus… Did tou have a look at the lovely little Guitar Amp I’ve made
Dalton Napier

 

Hello.

On maker pro there is a thread about the color organ @Ya’akov mentioned:
https://maker.pro/forums/threads/color-organ.268022/

Bertus

Hey there… what I’m wanting it to do is to have the LED’s ‘just on’ like a real hob would look with the Gas just turned ‘ON’, and then to glow brighter and track the sound level as the volume increases
Will that kit do that… r is it purely like an on/off switch plz
Ta
Dalton

 

Hello @Ian0 …I have no idea about how this ‘Forum' thing works… I’ve tried to DM you , but I’ll try to contact you this way… I like your attitude and I think you might be able to assist me in a quite unique thing I’m making… It’s a guitar amp that I’ve built into a Kids Wooden Stove , he he…
I'm going to send a picture here…
What I want to achieve is putting Blue LED's around each of the hobs, and having them barely on when the Amp is powered up… and for them to brighten up ( if possible to glow more intensely when as the Audio Level increses ) the Amp has a spare 240V socket already inside…Elegance is more important than cost or circuit complexity
Thanks for looking
Dalton Napier.

Yes - it should work fine. But use the circuit from post #17 not post #14, because I drew one transistor back-to-front in the post #14 diagram.

 

Yes - it should work fine. But use the circuit from post #17 not post #14, because I drew one transistor back-to-front in the post #14 diagram.
[/QUOTE

way hay! I’m so happy you got back to me So will that circuit do what I’m trying to do with the Guitar Amp ?
I’ll have a look now at that design
Thanks again
Dalton

 

hi again… will this design be able to control a string of BLUE LITTLE LEDs ?
Ta
Dalton

 

Hello,

Looking at the schematic in the thead on maker pro, the bottom channel uses blue leds.
Copy that to the other channels and you will be fine.

Bertus

 

hi again… will this design be able to control a string of BLUE LITTLE LEDs ?
Ta
Dalton

Because it uses transistors not op-amps it will run on higher voltages, so you can put quite a few LEDs in the string.

 

hi again… will this design be able to control a string of BLUE LITTLE LEDs ?
Ta
Dalton

What you may need depending on LED current is possibly a MOSFET driver. That or you can string your LEDs is series. A simple NPN transistor like the 2N2222 will easily get you 500 mA. The color organ linked gives you 3 channels responding to the audio frequencies. While today most folks like driving LED intensity using the PWM I mentioned earlier the color organ circuit should also work fine. Just a matter of playing around to get the exact desired effect you want. I would take the audio from the speaker leads. The color organ circuit offsets the op amps + inputs, that's what the small lower left U2 is about. There is a few ways to get where you want to go.

Ron