In this Instructable I will make a dark sensor without using a breadboard, solder or a printed circuit board.
Step 1: What You Need
What you need-
1 9v battery clip (I made mine)
1 transistor (BC547)
2 resistors (I don't know their ratings)
Connect one wire on the switch to one wire on the battery clip. I twist the wires to connect them.
Attach one wire from the LED and one wire from the Photoresistor to the one wire on the switch that is not connected to the battery clip.
With the LEDs wire that is not connected to the switch Attach it to the emitter on the transistor. The emitter on this transistor is the wire to the right when you look at its flat side.
Now connect the base (the middle wire) on the transistor to the Photoresistor's wire that is not connected to the switch.
Now with the collector wire (the left wire) connect the resistors. The resistors will reduce current going to the LED so it won't burn out.
Now connect the resistor wire that is not connected to anything else on to the other side of the battery clip. Its finished! :)