Speaker Indicator Light

[motorone]

Ok, I have a question for the electronic geeks out there. I have multiple scanners with their own external speakers. The speakers are mounted together. I would like to put indicator lights in the individual speakers so I can easily see what speaker is talking. I know it can be done, but I'm not that smart. Could some one out there help me with this project. Thanks.

 

[Al42]

Two ways I can think of off the top of my head:

Some little 12 volt "grain-of-wheat" bulbs (RS sells one kind) - put one across the two wires of each speaker. You can "mount" them in a little (about 3/16") hole with a drop of Silastic or hot-melt glue.

4 #47 bulbs - connect them in a "diamond" - each bulb to the one at its two corners. Connect the scanner to two opposite corners (say left and right) and the speaker to the other two (top and bottom, in this case). Adjust the volume so that the lights are just short of turning on with no speech. (It should be a pretty broad adjustment - where you have it now will probably work.) We used to use this as a cheap squelch - you can adjust the volume so that the hissing won't come through the speaker, but anything louder than that will.

 

[motorone]

The 12v grain of wheat sounds the the way for me. I guess I just over complicated the whole thing. I also never thought 12v. I was thinking in milli volts. Did not think 12v would work. Thanks for the help.

 

[Al42]

Well, they won't light up the room but, with enough volume, you'll see which speaker has audio on it. If you can find a 6 volt g-o-w bulb it might be a bit brighter.

 

[z96cobra]

I think I would go with LED's, since they can produce more light at lower power (volume in your case). You can also get 'em in a bunch of different colors, so you could "color code" your speakers incase the room lights are turned down.

Just my $.02,
Roger

 

[motorone]

I did a quick test and it does work. The one problem is the volume has to be up quite loud to light the bulb. I will have to put a volume control between the light and the external speaker. This will alow me to increase the source signal to drive the light and still adjust the volume of the external speaker. Not to complicated, even for this novice. Thanks for all your ideas. Great help.

 

[W4KRR]

I did a quick test and it does work. The one problem is the volume has to be up quite loud to light the bulb. I will have to put a volume control between the light and the external speaker. This will alow me to increase the source signal to drive the light and still adjust the volume of the external speaker. Not to complicated, even for this novice. Thanks for all your ideas. Great help.

You might try a hobby shop for some lower voltage grain of wheat bulbs, like 6 or even 3 volts. Model railroaders use these types of bulbs a lot.

 

[Al42]

I think I would go with LED's, since they can produce more light at lower power (volume in your case). You can also get 'em in a bunch of different colors, so you could "color code" your speakers incase the room lights are turned down.

Only 2 problems with LEDs. They're DC devices, so you have to use either series diodes or bypass diodes (forward voltage will cause avalanche, which will cause failure), and they run on 2 volts or less, so you'll probably need a series resistor with most speakers. 1 g-o-w bulb is cheaper, and you can use nail polish or hobby enamel (or even Easter egg dye) to color them.

 

[Nozzleman71]

Anybody got a video of how to do this, or maybe a link ? Thanks

 

[Nozzleman71]

Bump

 

[N9JIG]

See http://forums.radioreference.com/un...-carrier-indicator-light-uniden-scanners.html for N1SQB's work on Carrier Operated lights. I have done this mod on a dozen of my radios and it works great.

You can see them in operation at http://forums.radioreference.com/pictures-your-shack-mobile-setup/294794-n9jig-racks-shack.html

 

[Nozzleman71]

See http://forums.radioreference.com/un...-carrier-indicator-light-uniden-scanners.html for N1SQB's work on Carrier Operated lights. I have done this mod on a dozen of my radios and it works great.

You can see them in operation at http://forums.radioreference.com/pictures-your-shack-mobile-setup/294794-n9jig-racks-shack.html

Thanks, i may have misunderstood what i read but I am looking for a way to put a light on the extension speaker, not the one on the radio. I am a amateur with wiring stuff so it may be way over my head.

 

[N9JIG]

Duh, That's what I get for not reading the whole thread and when I did read it I was half awake...

 

[gewecke]

Radio Shack actually marketed a 12volt amplified speaker which already had a red indicator light which was active anytime there was audio. 10 watts if I recall.
I'd have to look up the model number but I remember it was a pretty good speaker.
I modded mine with a spdt switch for a second input jack which worked really nifty.

Found it, Model 21-541 was the speaker, and the directions even include the schematic!

Here's a great link for it,

http://www.eham.net/articles/23762

73,
n9zas

 

[KE5MC]

I think LEDs are the solution. OP has already tested bulb and identified having to turn the volume up high to light bulb. Needing to add a pot. to control volume to speaker. So he is going to have to do more than just put the blub across the speaker.

The sensitivity of the LED is just what is needed which can be controlled by a series resistor, which is common anyway. LED would be quicker to respond, have higher impedance across speaker and comes in different colors by design. LEDs do not have great PIV ratings compared to 1N4000 series diode, but in an audio circuit I don't believe the AC of the audio will be a problem.

I might have to get the breadboard and some parts out to play around with. I will post the results in a few days.

Only 2 problems with LEDs. They're DC devices, so you have to use either series diodes or bypass diodes (forward voltage will cause avalanche, which will cause failure), and they run on 2 volts or less, so you'll probably need a series resistor with most speakers. 1 g-o-w bulb is cheaper, and you can use nail polish or hobby enamel (or even Easter egg dye) to color them.