Disposable cameras contain very powerful circuitry that convert 1.5 volts to 300 volts in order to set off the flash. This log shows how to modify the circuit in order to use a double a battery to light up a 10 watt fluorescent bulb.
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Having worked in a photo lab before the days of digital cameras I have accumulated a mass of disposable cameras. There are various website pages on how to modify disposable camera circuits for different uses and here I will demonstrate the process so you too can build your own nightlight. Watch the video demonstration at the bottom.
Disposable Kodak camera
Double a battery pack
First you need to dismantle the camera using a flat head screwdriver. Remove the battery from the bottom of the camera before continuing to pull apart the rest of the camera.Be very careful when doing this as touching the capacitor inside can give you a nasty shock. The shock is enough to throw your arm back involuntary and the leaves and aching in your fingers for a while. The capacitor is located at the top of the camera, and as soon as you have exposed the capacity connections you should short the capacitor using a non metal handled screwdriver. Weight about a minute, ensure the capacitor out again.
Continue tearing apart the camera until you have extracted the circuit board. Bend the capacitor and the led light into an upright position and use the wire cutters to clip the connections in order to remove the components. If the lead light does not have long connections you may need to use a desoldering kit to remove it. Remove the flash unit or in my case i had to cut the wires that were leading from the trigger transformer to the flash, and the wires at each and of the flash before removing. You may need to use a desoldering kit to remove the solder points in order to remove the flash unit.
On the underside of the circuit board you should notice a round metal component that acts as a switch to charge up the capacitor. This is the button that is pressed on the front of the disposable camera when you want to charge the flash. Use a screwdriver to peel off the metal plate revealing a centre connection surrounded by three peripheral connections. You will need to connect the centre to one of the outside connections using a soldering iron. If your battery pack does not have a switch, you can solder in a switch leading from the centre connection here, to one of the outside connections.
Look around on the top of the circuit board for a diode. Some kodak cameras have two diodes, and I have not been able to get these cameras to work for this purpose. You will notice the diode has a white strip on one side of the black part. You can either sold or a wire to this side of the diode, or use your wire cutters to clip the diode at this point. The picture here shows the diode has been cut, and later a wire was soldered to it.
Pull apart your fluorescent bulb and remove the circuitry revealing the wires that lead into the gaseous tube.
The circuit is now ready to connect to a fluorescent bulb for testing. You will notice the battery holder is still connected to the circuit board. In my case, I had to cut these metal connections off in order to fit inside the fluorescent bulb. After doing this i soldered wires to the bottom side of the circuit board at the battery points. To test that you're circuit works, connect alligator clips to each of the metal connections of the battery holder. Connect another alligator clip to the end of the diode and another alligator clip to any other metal connection on the board other than the battery connections. Connect the other end of the alligator clips to the fluorescent bulb wires. Obviously the alligator clips on the battery connections will connect to the battery.
Once you have your circuit working, you can clip the corners off the circuit board and remove the battery terminals in order to fit the board inside the fluorescent tube cavity. I soldered wires from the fluorescent tube onto the circuit board and wires from the battery pack on to the battery points on the board after feeding them through the bottom part of the fluorescent bulb cap as shown.
The unit was now put back together and mounted onto the battery pack. I had to remove the original metal connections on the bottom of the fluorescent bulb in order to mount it on to the battery pack.
The battery pack I used had an on/off switch and after finishing the project I could simply flip the switch and my flouro made a handy night light. I also tried using a six volt battery to run the light all night, and found it had burnt out the transformer by morning time. It looks like this circuit is limited to three volts but will also work on 1.5 volts.