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Topic: Simple LED meter? (Read 2480 times) previous topic - next topic

The_Bongmaster

Can someone help me out? :)

I want to make a simple LED meter (VU?) that comprises of 5 LEDs, 2 green, 2 yellow, and 1 red, voltages at 2.2 and 2.3 volts.
I need to know what resistor values i would need. This circuit does not use any chips or transistors (i have seen the kit but no schematic)
all it uses are LEDs, resistors, and a diode, a capacitor too.
Its use wil be for adding into some speakers, or on the front panel of a pc to show sound level, and I really want it simple as possible, no chips or transistors (I cant get them easily), resistors and LED's I can get easily tho. and the kit i have seen online only uses them and a diode and cap.

Can someone throw up a diagram and list suitable resistors for such a thing please? :) i am still learning this stuff and this will help.

thnx ;)
B-dui in creation.

The_Bongmaster

anyone? :o I'm still searching but haven't found anything yet :(

realy could do with the help, I know its prolly simple but thats only if you know how..
B-dui in creation.

Grumpy_Mike

I think the problem is that no one can see where the Arduino fits in.

Also what voltage will be driving this? Is it straight from the speaker output of an audio amplifier or is it on the input side. Asking for something without transistors in it limits you to what can be achieved. You need a largish voltage that is probably not available on your system without amplification.

The_Bongmaster

this is the bar sport section ;) ie: non arduino goes.

it will probably be driven direct from soundcard/mp3 player. I could probably drop the voltage a bit b4 it is need be, i just want to try it out so i an understand more, like i said i have seen the kit but they give no info about it and the image was too small to se the resistor values.
B-dui in creation.

Grumpy_Mike

Your problem will not be too much voltage but too little.

OK it's a bit tricky without a diagram but attach a diode Anode to your sound source, connect a resistor (510R or so) from the cathode to a low power LED and the other end to ground. Now repeat this arrangement and hang it not from the sound source but from the cathode of the first diode. Repeat again connecting it to the cathode of the second diode.

So this looks like a string of diodes in serese from each junction of cathode and anode you hang a resistor and LED to earth. If the audio signal is over 0.7V the first LED will light, if its over 1.4V the first two will light, if it's over 2.1V the first three will light and so on. Do use low power LEDs the sort that will only draw about 2mA. Also the circuit might distort your audio signal a bit.


Can you follow this?

The_Bongmaster

#5
Jun 17, 2008, 08:06 pm Last Edit: Jun 18, 2008, 12:23 am by The_Bongmaster Reason: 1
thnx :)

hmm sort of, might need a diagram if its possible :)
B-dui in creation.

lilpunk1302

http://www.google.com/search?hl=en&q=LM3915

All in one solution.

Google for DIY VU Meter.

Grumpy_Mike

Quote
http://www.google.com/search?hl=en&q=LM3915

All in one solution.

Google for DIY VU Meter.


Yes but the original question asked for a circuit without any ICs  ::)

Here is a diagram of what you were not able to grasp from an explanation  :-? :o

.

Just keep on extending it for more LEDs.

The_Bongmaster

thnx that makes more sense :)
B-dui in creation.

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