This instructable will guide you through making a computer controlled low voltage device.

What you will need:
1 a old ps/2 or sub keyboard
2 some low voltage relays
3 some wire

Optional stuff
1 a nice box/case
2 dip socket
3 solder
4 led

Tools:
scissors
soldering iron
screwdriver which fits in the screws in your keyboard

Step 1: Opening the Keybord

Take your screwdriver and unscrew all the screws in your keybord. Look under stikers and those little rubber feet for more screws.
open your keybord.
throw away the white plastic sheets but keep the sercet bord

Step 2: Using the Keybord Cercit

Ether wrap wires around the led pins or desolder the leds and solder wire insted. Then add hot glue tape to keep the wires in place. Dont make the wires too long. now strip the ends of the wires. there shood be 3 pairs of red and black wires. 1 for each led.

Step 3: Wireing the Relay

get your relay and wire it to keyboard as shown.
use tape on connections and-after you have tested it, on all exposed conductive material and to secure the relay.

Step 4: Prepareing Your Box [optinal]

get your box and drill 3 holes in it. 1 on one side and 2 on another. if you do this, cut your usb cable near the plug then thred the end of the cable at the keybord through the hole then reeatach the cable by striping the cut ends and linking each couler back togeter again.
in the other to holes, put the led in one and thred the wires through the other.
then screwthe box together again.

Step 5: Testing

first get a program like controlermate for mac or silamaler for pc and set it up so wen you press some unused buttons on your keybord the keybord in the cercit lights its leds.
then make the cercit in the picture. now press the buttons you assined on the computer. if the led lights up woo! if not, check led being the right way round, battreys having power, and that all conections are conectid correctley and that nothing is touching that shoudent be.

Step 6: Fnished!

yay you've done it!
now go find some Christmas lights or something with a switch and wire this in instead if a switch. bingo! computer controlled Christmas lights!
this is my first Instructable hoped you liked it.