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75 LED VU Sound Meter Answered

Hiya, i want to put 75 leds either side of my sub woofer which act as a sound level meter. 

there's a picture shown on how it would look like.

40 Green LEDs
20 Yellow LEDs
15 Red LEDs

im have difficulties trying to find the perfect circuit right for this project.

any ideas?

thanks in advance. 


You've got two issues here. 1. Getting a nice color organ circuit that responds to sound input. 2. Having a circuit to drive all the LEDs in a pattern you want. You could go with an arduino to analyze the sound and drive an LED matrix.

i didnt want to put a arduino because i need an external power source and cant divert it from my amp. i wanted something similar to LM3914 chips.

what were you going to light the LEDs up with?

i was going to use the 12v from the amp. but if i get an arduino board it too much hassle. and its going to me in a car. i rather keep it as simple as possible and cheap as possible.

You'll have a struggle to get a stock 3915 to drive that many LEDs. You need a shed load of external transistors too.

You STILL need power - the amp wont' supplyt it.