Here's a link to the wiring schematic that was removed
In this Instructable, I'll show you how to sync LEDs to music. I know this have been done before multiple times but this time I'll try to do it as clear and easy as possible. My camera is bad so please bare with me.
I've also made a video tutorial!
Step 1: What You Need
9 volt battery
9 volt battery clip
*TIP31 (Or other NPN transistor)
*220 ohm resistor
audio cable or old headphones
If you have a breadboard you only need:
a knife or scissors
(optional) 3 alligator clips
If you want to make it permanent you'll need:
Soldering iron and solder
(optional) project enclosure
Step 2: Assembly
1 Making it with a breadboard:
Start with connecting the 9v battery to the bus lane. Then put the TIP31 vertically somewhere near that bus lane.
Hook up the cathode (shorter lead) of the first LED to the collector (middle) pin of the transistor. Then connect the cathode of the secound LED to the anode of the first. The secound LED's cathode goes via 220 ohm resistor to positive voltage.
Connect the emitter of the TIP31 to ground on the bus lane.
Connect an alligator clip to a jumper wire and connect that jumper to the base of the transistor.
The other end of the alligator clip goes to left or right channel in the audio cable.
Connect another alligator clip to a jumper wire and hook it up to ground.
The other end goes to the power in the audio jack, there might be several power cables inside, any of them will do.
Copy everything if you want two channels.
2 Making it permanent (Both channels)
Solder both resistors to the positive end of the battery clip.
Solder 3 wires to the negative end of the battery clip.
Solder the anode (Longer lead) of one LED to the cathode of the other one.
Repeat above step.
Then solder the anode of the 2nd LEDs to the resistors
Solder two of the cables to ground to the emitter pins of the transistors.
The collector pins are soldered to the cathode of the two LEDs
The base pins are soldered to respectively the right and left channels in the audio cable.
The third cable to ground goes to the power cable in the audio cable.
If you want a switch solder the positive voltage to pin 1 on the switch and the
continiuing cable on the secound pin.