Jar Lantern





Introduction: Jar Lantern

About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author ...

The Jar Lantern is a contemporary take on the traditional gas lantern. It was inspired by seeing sunlight refract through my glass water bottle one afternoon, and thinking to myself that it was a bit like carrying a jar full of light. This brief moment of illumination sparked something in my mind that made me wonder how I could capture this experience more permanently.

While trying to bottle light may be a fool's task, I could at least try to recreate the sense of magic I had briefly experienced. After mulling over various methods of accomplishing this, I decided to make a jar with an illuminated floating light bulb. The beauty of this seemingly impossible object is that the light bulb has no clear power source, yet it seems so natural and familiar. The Jar Lantern tends to leave people both taken and dumbfounded by its simplicity.

Step 1: Go Get Stuff

You will need:

(x1) Jar**
(x1) CFL Bulb
(x1) Disposable camera
(x1) AA battery holder
(x1) Switch
(x1) Roll of magnet wire

**You can get the jars used in this project online, but only by the dozen from Daiso.

(Please note that some of the links on this page contain Amazon affiliate links. This does not change the price of any of the items for sale. However, I earn a small commission if you click on any of those links and buy anything. I reinvest this money into materials and tools for future projects. If you would like an alternate suggestion for a supplier of any of the parts, please let me know.)

Step 2: Open the Disposable Camera

Open up the disposable camera case. Be mindful not to touch the large capacitor which could potentially give you a nice jolt.

Step 3: Cut Away the Capacitor and Flash

Discharge the capacitor by bridging the leads with a long screwdriver that you don't care much for. Be careful not to be touching the metal part of the screwdriver while doing this. Once discharged, cut it from the board so that it will not recharge.

Also, cut the flash tube away from the circuit board.

Step 4: Hack a CFL

Use a pair of diagonal cutting pliers to make a hole in the plastic body of a CFL bulb.

Next, use this hole to insert a screwdriver and gently pry the the base apart from the glass tube.

Finally, unwind the CFL tube's wires from the posts on the circuit board.

Step 5: Bridge the Switch

Remove the push tab atop the flash charge switch.

Solder the switch's terminals together.

Step 6: Prep the CFL Bulb

Scrape the coating off the wires coming out of the CFL bulb using a razor blade.

Twist the wires together and tin them with solder.

Step 7: Remove Extra Parts

Remove any parts the stick out from the board such as battery terminals. However, remember to make note of which terminals on the underside of the board they are connected to for future reference.

I also removed the wire connecting the top of the trigger transformer to the flash tube for the heck of it.

Step 8: Trim the Circuit Board

Trim away any corners that have unnecessary electronic traces (or no traces at all).

Step 9: Prep the Magnet Wire

Strip away 1/2" of plastic coating from both ends of two 3" pieces of magnet wire using a razor blade.

Step 10: Hack a Camera Flash

Now is time to connect the wires to the board that will power the light.

Solder the first magnet wire to one of the terminals connected to the ground plane.

Solder the other wire to the terminal of the inverting transformer that the diode is connected to.

*** If you are confused, a more hands on way of figuring this out is to use aligator clip jumper cables to connect the battery to the board. The board should now be live, so be careful of high voltages!

Using another cable, connect one of the bulbs leads to ground. Finally, connect a fourth cable to the other battery lead. Briefly touch this wire to various spots on the board until the bulb lights up. Once its lit, you have found the proper connection. ***

Step 11: Connect a Switch

Trim the battery holder's red wire in half. Solder the trimmed pieces to the center terminal of the switch and the red wire still connected to the battery holder to the switch's outer terminal.

Step 12: Drill the Lid

Drill a 3/16" hole near the outer part of the lid for mounting the switch.

Step 13: Mount the Switch

Pass the switch up through the underside of the lid and lock it in place with its mounting nut.

Step 14: Connect Power to the Camera Flash

Solder the red wire from the switch to the spot on the camera flash circuit board where the positive terminal of the battery was connected.

Solder the black wire to ground.

Step 15: Hot Glue

While I am not normally a fan of hot glue, it is the perfect adhesive for connecting the circuit board and battery holder to the inside of the lid.

Center them inside the lid and then glue them in place as flush to the lid as possible.

Use a generous amount of glue, but be mindful of not getting any on the lid's inner edge, or it will no longer twist shut.

Step 16: Connect the Bulb

Solder one of the magnet wires to each of the CFL bulb's leads.

Step 17: Insert the Battery

Insert the battery into the battery holder.

Step 18: Twist On

Twist the lid onto the jar.

Step 19: Power!

If the lantern is not already on, power it up by flicking the switch.

Step 20: Illuminate the Darkness

Go forth and make good use of your new lantern.

11 People Made This Project!


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Please be positive and constructive.




how many volts is coming out from the camera board?

7 replies

roughly 300, so quite a bit. very low amperage though, and it's DC current.

You can have a very high voltage but without much amperes, you won't get as much as a tiny jolt like when you rubbed yourself and touched something and gave you a jolt.

It is not DC, it is ac at a fairly high frequency. Usually somewhere near 27K Hz.

but don't seemed that it provides a parts list.... thanks anyways.....

found this link that gives the schematic and parts list for building a flash circuit.... http://www.diyphotography.net/how-to-build-a-flash-with-an-optical-slave

Depending upon which board you start with , you can get 350-400 volts output.

What are the odds that I found THE same jar today at a dollar store?

14, 8:02 PM.jpg
1 reply

How long will the batter run the CFL?

What about using an LED bulb?

4 replies

No, an LED bulb will not work for this. The technology is completely different. The real purpose of this instructable is to re-purpose a dead CFL where the circuit died but the bulb part is still good. In a CFL bulb the voltage is stepped up (300 volts), in an LED bulb the voltage is stepped down (2 to 3 volts).

Hope this helps.

This thing is rather like a Jeanna's light in a jar using recycled parts.

The answer to that is a bit complicated, and at the same time not. Ohms law is the answer, but to run those cfl you need a high frequency high voltage and LEDs like low voltage dc, but you can use a joulethief for the LEDs. By theory you could have double battery life on LEDs vs cfl cos cfl have around 50lm/W light output and led can have about 100lm/W.

Cool instructable, thanks for sharing OP. I too am curious to know if an LED bulb would be a better choice in terms of battery runtime...maybe the OP hasn't responded because LED bulbs are more difficult to modify? I really don't know...

Hi Randofo,

Sorry for delay in getting back to you. I DID manage to get the circuit working and made a really nice jar lantern that works perfectly.Thanks a million for all your help.

Kind regards,


wow, i was actually considering making something like this!!!

Hi Randofo, Great instructable and excellent work.

Unfortunately,I have been trying to copy this project trying loads of different disposable cameras. when I very carefully cut a brand new working 12 W CFL bulb open it would not light at all. I did get an intact 3.5 LED lamp to light brightly but it's strobing ALL the time at a constant rate (at about 1Hz or slightly less). I can't get it to light continuously no matter where I place the bulb contacts. When I tried another unopened CFL it worked but strobed again, no continuous light. I carefully opened another CFL without breaking the glass. Snipped off the pcb and sanded and paired the 4 wires etc - no joy!I I have tried Kodak, Le Box AgfaFoto Fujifilm etc cameras every which way. Any ideas? I'm in Ireland. Is it possible that all disposable cameras sold in Europe have different circuitry which pulse the high voltage unlike the ones sold in the US? I would have thought that that would be unlikely.
I would be most grateful if you could tell me how I can get a CFL to light continuously. Thanks,

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