This is my first project and my first instructable so bear with me.
Also this is still a work-in-progress since there is so much I plan to do with this project. I will keep updating this if possible with updates such as not relying on a microphone, driving more LEDs, ect.
Step 1: What You Need.
1 - LM3914N LEd driver
1 - 1k resistor
1 - 1M resistor (the picture shows a 10k resistor but I got best results with 1M, play around with this value to get best results)
1 - 1uF electrolytic capacitor
10 - LED (your choice of colors)
Solderless bread board or whatever else you want to build on
4 AA batteres
Switch is optional
Step 2: Build the Circuit and Connect the Sound Source
Pin 5 may get a little confusing. What happens there is pin 5 goes to node "A". Node "A" attaches to a resistor (1M) which goes to ground. Node "A" also connects to the negative of the capacitor.
Other than that it is straight forwards. The negatives of the LEDs face the chip. The positive ends of the LEDs are connected to the source.
The Input. Now this is porbably the most important step. The input comes from sound card on my computer (to be able to listen and view this effect you need to get this: http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10218&cs_id=1021802&p_id=667&seq=1&format=2&style=
The male end of the above goes to the sound card where you speakers are now. One female end is connected to the speakers you just unplugged. The other end will be this:
You take 1 end of this and cut it and split the wire to look like the picture shown.
Step 3: Turn on Some Songs and Sit Back and Watch
This is a note from where I got the circuit drawing: "I like to see lights move to music. This project will indicate the volume level of the audio going to your speakers by lighting up LEDS. The LEDS can be any color so mix them up and really make it look good. The input of the circuit is connected to the speaker output of your audio amplifier. You want to build two identical units to indicate both right and left channels. The input signal level is adjusted by the 10k ohm VR. If you wish to make a very large scale model of this unit and hang it on your wall there is an optional output transistor that can drive many LEDS at once. The unit I built drove three LEDS for each output. The sequence of the LEDS lighting are as follows Pin 1, 18, 17, 16, 15, 14, 13, 12, 11, 10."
I only did this for 1 channel but plan add improvements.
Take a look at the video for results.
Some things I need to fix are:
All of the 10 LED's do not light up. I need to make an amplifier of some sort but dont have too much expierence in this.
Make this work with a microphone element
Add function for two channels
Add multiple LED's in place of each 1 LED (maybe 3x10 = 30LED)
Also figure out how to connect the microphone element as I have no idea what the picture below shows