LED Meter

[samtheboxer]

hello all, thanks for all your help with the LED Strobe light, i got it working, then quickly fried it will 11 volts! Oh well, i have a USB pic programmer on the way, so ill wait till i get that and try again..

in the mean time, im looking for a circuit to include in my CMOY audio amplifier that will show the output of the music with a 6-8 led meter. Does that make sense? I forget the actual name for the meter, i want to say a UV meter, but i dont think that is right...basically, it "bounces" with the beat...

any suggestions?

thank

 

[ronsimpson]

audio meter using LEDs

UV meter 10LEDs
https://www.electro-tech-online.com/custompdfs/2007/06/LM3916.pdf
The LM3916 works well.

 

[Norlin]

You can also check out the following velleman kits:
**broken link removed**
**broken link removed**

 

[samtheboxer]

UV meter 10LEDs
https://www.electro-tech-online.com/custompdfs/2007/06/LM3916-1.pdf
The LM3916 works well.

thanks, it works great. it may not be the most accurate, but its eye candy, and thats what i was looking for.

The only problem is that its not too sensitive. I have it hooked up to me CMOY amp and it really moves at higher volumes, but i usually dont listen to it that loud. Can i pump up the signal using some transistors? or would i have to run the signal through a second amp and bump it up that way...

thanks

 

[audioguru]

Hi Sam,
You forgot to attach the schematic of the circuit you built with the LM3916.
The first circuit in the datasheet has two resistors that make its max sensitivity low. It is 10V full scale. If you wire it like this then the full scale sensitivity is 1.25V.

The LEDs will be blurred and dim with music. It needs to have the peak detector circuit shown in the datasheet for the LM3915 to stretch short duration peaks so you can clearly see them.

 

[samtheboxer]

Hi Sam,
You forgot to attach the schematic of the circuit you built with the LM3916.
The first circuit in the datasheet has two resistors that make its max sensitivity low. It is 10V full scale. If you wire it like this then the full scale sensitivity is 1.25V.

The LEDs will be blurred and dim with music. It needs to have the peak detector circuit shown in the datasheet for the LM3915 to stretch short duration peaks so you can clearly see them.

**broken link removed**

Here is the schematic i used. I dont have pin 9 connected.

 

[audioguru]

Add this peak detector with gain circuit. The MC33171 is an improved version of the old single supply dual opamp the LM358. An ordinary 741 opamp won't work.