Here is an idea for a nice string of Christmas lights.
It is made by bright ping pong balls slowly changing their color through the sequence RED, GREEN, BLUE, YELLOW, CYAN, PURPLE, WHITE and again ...
At first all balls change color at the same time, but due to the less than perfect LED chip internal clock, after some minutes each led has its color different from the others !
Step 1: Parts and materials
- slow flash color LEDs (browse ebay with these keywords), I used 30 of 5mm type
- white plain ping pong balls (you can find the by dozen on ebay or just on your street stores)
- a simple pvc insulated bipolar copper cable (I used a white one, but choose every color you want)
- a wall wart power supply (I used a 12V/1000mA one, but every type from 7V upto 13V works)
- an LM317 regulator IC (a 7805 type can be used, but in other way, see next steps)
- a 2.2 ohm 1.5W resistor (or a parallel of higher value resistor group, see next steps)
- a 1000uF/16V electrolytic capacitor (470uF or 2200uF work as well)
- heat shrinking tubing (2-3 mm type)
- clear hot glue (with the relevant gun of course)
- moderate power soldering iron
- typical christmas plastic fake green festoons (optional)