Intro: Self-Lighting Light Bulb
My brother was married on Halloween, and the theme was the Addams Family. Being the uncle, I decided to go as Fester and made a nice light bulb that I could stick in my mouth and light up. This is a fairly simple project that can be completed in an hour if you choose. This is a fun project to make with some burned out light bulbs, wire, batteries, and an LED.
I made this at the TechShop. They have all the tools and wire/solder for your use. It makes this easy.
Step 1: Items Required
These are the items I used to make this. I picked everything except the light bulbs from Radio Shack, but you should be able to use similar components purchased anywhere.
- 3x 1.5v small button cell batteries. (This leaves you with 4.5v power.)
- One High Brightness White LED. Mine is rated for 3.4-4v max, so we overdrive it slightly.
- One Tact Switch. Be careful on the size. I show 5mm height in the picture, but the ones I used were slightly taller.
- Light Bulbs. Small cheap ones. Burned out ones work better since they're free. The white frosted ones look better but are easier to leave marks on the inside.
- Wire. Don't need much.
- Electrical Tape
- Soldering Iron, Wire cutters/strippers, helping hands, etc.
- Hot Glue Gun
Step 2: Solder Wires Onto the LED.
If you have a 4pin LED, as I do in the picture, you'll need to solder some wire leads onto the LED itself. If you look at the LED, you'll see that there are basically only 2 pins that matter. (2 pins on each side are connected.) I made one wire slightly longer than the other to tell them apart and to provide a little room for the switch on one side.
Step 3: Add on the Switch.
The helping hands really help with this. If you don't have a pair of helping hands, you can lay the spool of solder on the ground and add some solder to the wire and switch separately and then solder them together.
Keep note that, like the LED, only two prongs on the switch matter. (In the picture, the two bottom ones and two top ones are connected, so you'll need your wires to go from one on the bottom to one on the top.) Connect one wire from the LED to the other prong.
Step 4: Connect the Batteries
Now is a good time to test everything and make sure they work. You'll want the Anode of the LED connected to the positive side of the batteries, and the Cathode connected to the negative side. It doesn't really matter which side the switch is connected to, but the LED only allows current to flow one way. Test it by pressing the wires against the batteries and pressing the switch to see if it lights up. If not, flip the batteries and test your connections.
Once you get it working, I personally added a little solder to connect the wires to the batteries. Just note that solder will not stick to the batteries easily or reliably, I just did it to add a little extra security.
Now I wrap the batteries in electrical tape. This will keep them tight together and works fairly well. Once you do this, you should be able to press the switch easily and the light will turn on.
Step 5: Take Apart a Light Bulb
Be careful during this part. It is probably wise to wear gloves and safety goggles just in case the light bulb breaks.
Carefully, hold the light bulb and start trying to twist the metal off of the bottom. It's held together by a cement that isn't normally very strong. On old light bulbs, it will probably twist right off. If you use a newer light bulb, heat up the metal part with your heat gun (or any other method you can think of) and it should loosen up. Using a heat gun, I've never had any trouble taking off the metal bottom. You might have to twist it to break the wire connectors that are attacked to it, but they're small and come apart fairly easily.
One you separate the two pieces, I use a pair of pliers to scrape off some of the cement. It comes off pretty easily.
On the bottom of the light bulb, you'll see a glass pole coming out of the center. You can apply pressure (I use the table) and break this off pretty easily. After that, you'll need to find a way to break the glass on the bottom carefully. Some techshops have a glass cutter that will make this an easy task, but if not take a screwdriver or pick and gently chip at it.
As expected, this is the most difficult part. You need to break the glass carefully enough that it doesn't break too much and make it so you can't reattach it. You also need to be especially careful because if you break pieces into the light bulb, they will scratch the white frosting. (Even touching it will leave marks. Unless your really REALLY gentle, the wires inside will scratch it. (I haven't been able to make one perfectly without these scratches yet, as you can see in the next step, but small ones generally don't matter.)
Step 6: Insert the LED
Take the metal bottom of the light bulb and drill a small hole in the side that is slightly larger than the switch toward the bottom of the bulb. (You want to make sure it's below where the glass will go when you put it back together.) Use a hand drill if you have one, but the metal is thin and it's easy to punch through. You'll want to make sure you go from the outside in to prevent metal shards from pointing outwards. (Even though it's easier to punch it from the inside while it's laying on the table.) One the hole is there, you should be able to put the whole package into the metal part as shown in the picture. Test it a few times to make sure it still works and the button is stable. (The battery pack and the hot glue will help stabilize it.) Also make sure you have room on the edges for the glass to fit.
Start adding hot glue liberally inside the metal container. I filled all the extra space with it just to help hold everything in place. Test the switch make sure it still works and insert the glass. (If you want, you can twist the wires to change the distance it goes into the light bulb. It should be about in the center to look right.)
While the glue is hot, press the glass into the metal. I used my heat gun to make sure the glue was hot and ensure it didn't break the glass. It should slide in pretty easily. You can light it up now and make sure it looks ok during this part. With the heat gun, there is no real urgency, so you can adjust the LED wires to position it however looks the best.
Step 7: Add a Bead of Hot Glue to the Outside to Finish It
Add a small bead of hot glue around the rim of the metal to help secure the glass. (I added a little more than needed in the image, but you can smooth it out to make it look better.)
Now you should have a light bulb that lights up by simply pressing the button. I don't suggest putting it in your mouth as I did, but if you do, make sure you clean it really well. :)