How To: Make LEDs Dance to Techno Music

You must have seen some expensive mp3 players and CD players which have LEDs fixed on them and they dance to the tune looking really pretty.

Imagine you could make your own LEDs and configure them to dance to Daft Punk or Swedish House Mafia. I'm going to tell you how it can be done at your home and with a lot less money. You just need a few components and a little bit of concentration before we can get the party started!

Step 1: Get Your Components and Equipment

There are a few things you may need to start with. Some, you might find in your home; others are easily and cheaply available at your nearest electronic component shop.

• LEDs
• An Old Headphone/Hands Free Set
• Transistor (TIP-31)
• Resistors (500 ohm and 1k ohm)
• PCB/Vero Boards
• Soldering Iron and Soldering Wire
• Wire and Wire Cutter
• AA Batteries/one 9V Battery (The use of any battery depends on how many LEDs you are using and the connection scheme (parallel of series) A series connection will need more power a parallel configuration like I am using here will require less energy)

Step 2: Connecting the Circuit

Follow the steps below and be sure to read the safety precautions I have mentioned at the end.

1. Place all LEDs on the Vero board, pins down. Take care of the LED polarity (the longer end is the anode!). Connect them in a parallel configuration by soldering all the negative ends together and then soldering all the positive ends in the same fashion as shown in the circuit diagram above.
2. Then connect all the positive ends that are soldered together to the collector of the transistor (take care of the pin configuration of TIP-31 as given earlier).
3. Connect all the negative ends (which are soldered together) to the positive end of the battery.
4. The base of the transistor is to be connected to the 500 ohm resistor and the emitter to the negative end of the battery.
5. Take the old handsfree that you have and cut off one earphone. Out come the two strands. Solder both strands across the resistor (Polarity does not matter here).
6. All you now need is to plug in the audio jack in to your iPod or mp3 player and enjoy the lightening music!

Step 3: Make It Look Good

If you want to improve it aesthetically you could probably improvise with a plastic/cardboard box and make some holes through it and place the Vero board inside it such that the LEDs show at the top of the box and then you could spray-paint it, well, golden or silver, whatever you like!

Step 4: Remember Safety!

1. In the case of LEDs, polarity matters where with the ear phone strands it does not.
2. Handle LEDs with care because they are susceptible to burning by a violent current surge.
3. In case of a 9V battery, a resistor of 1kohm can be placed in series with the battery if the LED's are susceptible to burning.