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Large VU Meter

chris8477a

Dec 13, 2011
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Hi All

Basically, I want to make 2x Large VU meters... aprox size 6" wide x 3'ft long...

have attached a basic design pic to give you an idea.

The Blue Design will be spaced 10mm LEDs, In total 24 per section = 288 LED's, all run from 240V AC converted to 12V DC.

Obviously 1 Level per row totalling 6 Levels of Volume response.

I have no idea for the schematic or values etc to use.... I have 6x LM2901N chips from a VU meter that I have on a mixer dec, can I use these??

Please help, tried to find some sort of schematic but to no-avail......

many thanks

Chris :confused::confused::confused:
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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I'd start by looking at the LM3915

You'll get 10 LEDs that respond in a logarithmic way to voltage. There is no reason to use all 10 outputs if you really only want 6.

From each output you'll need a driver circuit to drive all the LEDs you require.
 

chris8477a

Dec 13, 2011
24
Joined
Dec 13, 2011
Messages
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VU Meter

Hi

Thanks for the quick response,, So Ive found this schematic based on the LM3915.

Looking at this, pins 1, 10-18 are obviously the LED's... one assumes that I can the run multiple LED's from the same point. Can I connect 12-24 LED's to the one pin?? or would I need multiple units of the LM3915.

Having read a few sites about this IC, cant find anything about the "Mode Pin 9" how is this used?

Lastley for now (lol), Alot of people have said that their Audio output isnt strong enough and that should include an Op-amp to boost the signal, (LM386),,,,, I have a few TL072cp wich I believe is a general purpose Op-Amp.. is this compatible.?

thanks

Chris
 

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Looking at this, pins 1, 10-18 are obviously the LED's... one assumes that I can the run multiple LED's from the same point. Can I connect 12-24 LED's to the one pin?? or would I need multiple units of the LM3915.

No, from each output you would need a driver of some sort to allow multiple LEDs. This may be as simple as a mosfet.

edit: This shows one of these devices being used to drive a larger load (in this case a relay)

Having read a few sites about this IC, cant find anything about the "Mode Pin 9" how is this used?
What you should be reading is the datasheet. Use that first, then look at what people say on the web if you want some more examples.

Pin 9 is mostly used for the dot/bar mode, but it also has other uses.

Lastley for now (lol), Alot of people have said that their Audio output isn't strong enough and that should include an Op-amp to boost the signal, (LM386),,,,, I have a few TL072cp wich I believe is a general purpose Op-Amp.. is this compatible.?
They should be fine.
 
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