In this instructable I will show you how I made a simple color changing light bulb night light. This is the first project in a series of projects featuring low cost color changing LEDs salvaged from tealights that can be purchased at big lots.
Some background on the tealights
Each tealight has a color changing led, a cr2032 3v battery, a battery holder, and a waterproof case for it all to sit in. Each package of lights contains 2 light assemblies and 2 extra batteries. All together there is:
4x cr2032 3v batteries
2x color changing leds
2x battery holders
2x waterproof cases
In my humble opinion that's a pretty dang good deal for $2
Step 1: Materials
For this project you will need the following
1x burnt out light bulb that has been hollowed
1x floating color changing tealight from Big Lots (2 for $2)
1x Glue gun
If you wish to make it usb powered you will need
1x usb cable
1x 30 - 40 ohm resistor (I used a 33 ohm because its what i had on hand)
1x Soldering iron
Step 2: Disassembly
Go ahead and plug in your glue gun so it can warm up.
While you are waiting open the package and remove a tealight. Open the tealight by unscrewing the top from the base. remove the led assembly (not attached) and the battery.
Under the battery you will fins a small piece of paper or plastic insulating the battery from the contacts to prevent accidental lighting during shipping. Remove this as it will not be necessary.
Step 3: Glue Time
There are two paths you can take at this step. First would to leave the light bulb hollow. The second would be to fill the bulb with hot glue. I chose the first path to conserve on hot glue and time.
if you want to fill the bulb go ahead and do so. once its cooled off proceed.
Take the top of the light assembly (now with the led removed) and put a fairly good bead of glue around the edge. Do the same with the light bulb. Before the glue gets too cold press the two pieces together centering the bulb as best as possible. once its cooled add some more glue around the base of the bulb for extra support.
Step 4: Reassembly
Once the glue is cool and your happy with its appearance. reinsert the led assembly into the top of the case. Place the battery (now without the paper or plastic tab) Positive(+) side down. Screw the base onto the top until the light illuminates.
Step 5: Make It Usb Powered
To make it use powered you will need to hack the end of your cable off. Then strip the outside insulation and shield off. Cut the green and white wires back almost to where the outside insulation was stripped to and tape them apart.
Solder the 30 - 40 ohm resistor to the red wire. strip the black wire back.
Next drill a small hole in the case wide enough to pass the usb cable into. Push the cable through the hole and secure it on both sides with a bead of hot glue.
Solder the black wire to the spring. Solder the other side of the resistor to the base. Cover any bare pieces of the red wire with hot glue or electrical tape.
Screw the base onto the top and plug it into a usb port.
Step 6: Updates
As comments come in I will try to update this as much as possible.
Some other things I found:
With a neodymium magnet you can stick the bulb to a wall where there are Sheetrock nails