and here it is my first instructable :)
excuse me for my bad english i'm not good at spelling and i'm dutch so... please if there is something incorrectly spelled let me know then i can fix it or pay more attention to it
Step 1: Get the stuff
but what you will need is a LDR that has about 3500 ohm's when you expose it to a simple laser pen
mine didn't have that much resitance so i fitted a aditional risistor of 1500 ohms.
but that is all up to you
ok what you need:
A conductive lego strip
A lego brik
maybe an aditional risistor
Step 2: Constructing
next you need to get the condutest on the top exposed just cut them away with a knife or something. only 2 are needed so leave the rest the way the were if there is a rest.
first if you use an aditional resistor get some solder on the conductor. cut the resitor to the correct size and place it.
next you need te get the LDR on cut the wire's to the correct size and solder them to the conductive plate, if you have a resistor you need te get one wire to the other end of the resistor.