These light graffiti cans give the feeling that you're spray painting with light. Combine these with the free software at http://glowdoodle.com/ or http://mylightpainting.com/ and you've got a virtual 3D graffiti wall. You can also use these with a long camera exposure in a dark room.
This version is very easy to build and requires few tools. For building these with real spray paint cans, check out this tutorial:
Step 1: Gather Parts
LED in color of choice
Any type of Wire (22 Gauge stranded works well, 2 colors preferred)
Battery holder for 2 AAA or AA
Momentary Pushbutton Switch (Normally Open, or N.O. on package)
Masking tape (not shown)
Wirecutters (could get by with only scissors in a pinch)
Soldering iron & Solder (optional, can use tape, but recommended)
Drill and/or hand reamer
Hot glue gun & glue
Step 2: Add the Switch to the Cap
Drill a hole in the cap next to the spout. Add the switch. There is a nut that should hold it in place.
Step 3: Wire the Switch
Solder one short wire and one long wire to the switch. The long wire should be longer than the shampoo bottle. I chose dark green wire to represent ground because it is close to black.
Step 4: Add the LED to the Cap
Bend the LED leads at 90 degrees to face forward. Connect the negative side of the LED to the switch with via the short piece of wire from Step 3. Be mindful to keep all of your wiring inside the bottle.
On the other LED lead, connect your positive wire (in my case this was red). This should be long enough to come out the bottom of the bottle.
Use hot glue to hold the LED in place.
Step 5: Attach the Battery Pack
Connect the battery pack to the long ground and positive wires you've got going through the bottle. In these pictures, dark green is negative (or ground) and white or red represents positive.
Tape will hold the battery pack steady inside the bottle.
Step 6: Secure Wires and Enjoy!
Use masking take to keep the wires and battery pack in the bottle. Go to http://glowdoodle.com/ to test your awesome Light Graffiti Cans!
Add some dead coin cell batteries to simulate the rattling that normal spray paint cans have!