Step 1: How It Works
The circuit uses a LDR especially tweaked using a 270k resistor to turn on the night light when it starts becoming dusk.
The transistor in the circuit simply activates as the on switch when the light levels change.
Step 2: The Parts List
x10 white smt LEDs (XPCWHT-L1-0000-00C01)
Tin copper wire, any strong flexible gage.
Blank pcb breadboard.
3.6v Lithium ion battery
5.4v + solar cell
Step 3: The Circuit
The schottky diode is on the back of my solar cell between the positive of the solar cell and battery positive.
Depending on what value LDR you have, you might have to change your normal resistor value accordingly.
Use a variable resistor first to get the LEDs to switch on at the right light levels.
Create a ring of tin copper wire and a slighlty smaller one to fit inside and solder ends together.
Solder the negatives of all LEDs to one ring and positives to the other ring.
It can be tricky and the rings get very HOT!
Step 4: Future Reactors..
Also I've made a replica arc reactor from the Iron Man 1 movie, check out my other Instructable!