Music VU bar with 160 led diodes.

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Yeah i know that Mr RB, but i was woundering if i can use a computer psu for 12v and then an aux for signal
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Yes given that 160 LED's running at 20 Ma each would only need around 3.2 amps.

The problem as mentioned before is the total parts required. Somewhere around 800 - 900 individual components.

Using 6 channel comparators IC's you would need 27 of them with each channel plus LED taking some 5 additional components.
 
Today's music is heavily compressed so you certainly do not need 27 comparators. You can do it with only 10 comparators that are built-into one LM3915 IC.
Then you need transistors to drive the series strings of LEDs and their current-limiting resistors.

The comparators are half-wave rectifiers so the LEDs will be lighted for half the time then the average current is half.
A peak detector circuit will make the LEDs appear brighter and better.
 
At this point he is not going for a true VU meter function. Rather a sort of milli VU meter in a way.

Even with the compressed music a simple low pass filter should get his LED string pumping right along to the bass notes just the same regardless for its validity to be any representation of a true VU meters function.

He just wants a long string of pulsing lights that react to an audio signal.
 
I have a VU meter. It is a string of LEDs driven from an LM3915 and an opamp peak detector circuit.
The input is an electret mic and the outputs have two red LEDs in series. It is powered from a wall-wart and/or a rechargeable 9V Ni-MH battery.

The LM3915 provides a range of 30dB and I added an AGC circuit to provide an additional 20dB.
 
tcmtech said:
The problem as mentioned before is the total parts required. Somewhere around 800 - 900 individual components.
Click to expand...
You can do it with fewer components, simply by multiplexing. e.g. using a 10*16 matrix you'd only need 10 resistors, 26 buffer transistors, a microcontroller and some input signal conditioning.
 
Just guessing the guy doesn't have a micro processor or any of the necessary gear and experience to program it.
 
tcmtech said:
Just guessing the guy doesn't have a micro processor or any of the necessary gear and experience to program it.
Click to expand...
He doesn't have (m)any of the parts yet I would think.

An Arduino, or Funduino (or mini) can be bought cheaply ($12 Funduino, $8 Funduino mini or $3 for a preprogrammed ATMEGA328 - latter two require a TTL serial adapter). These have a bootloader and don't require an extra programming circuit.

Depending on the number of LEDs used, an external shift register (or Johnson counter) can be used to provide extra outputs.

It makes for a pretty simple solution.

ADDED: the Funduino MEGA can be had for $16.50, and has more than enough pins to drive the the target number of LEDs.
 
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Nah, right now i got 0 components laying around
But the school is going to be closed for a month soon.
And i got some money burning a hole in my pocket
 
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