This tutorial is showing you how to make a box that flashes when someone opens it, using a disposable camera, a simple switch, a battery holder and of cause a box.

The result is shown in the video below. (In reality the flash is much brighter than the video might suggest.)

Caution! The electronics involved generates high voltage. Don’t be stupid.

Step 1: Acquiring the Electronics

First of all you will have to rip the camera apart. Make sure that the film is either of supreme unimportance to you, or that it is fully rewind. After that you should start with withdrawing the battery. You can usually find it on the bottom of your camera under some adhesive label and a plastic covering.

With the battery out of its housing you should have a god gap to insert a lever and to break the apparatus. If there are mechanicals parts flying around, never mind, we won’t need them today.

Now you should see something like the picture below. In my camera the electronics were held by two crews. That might be different with other cameras.

Be sure not to touch any of the electronics. They might be charged. Grab al large insulated screwdriver or pair of pliers, than touch the connections of the large capacitor. Make sure you don’t touch it with your fingers.

You now hold in hands the heart of your trap box.

Step 2: A Little Soldering

Now it is time for a little soldering. There are some things you won’t need any more or that should be replaced.

For example you will want to store the battery in a secure battery holder, the flash switch does not correspond to what you need and finally you want the capacitor to be charged at all the times.

When connecting the new battery holder make sure to have the happy little electrons float in the right direction.

When connecting the switch remember what you want. You want the flash to go of when someone is opening the box not when someone closes it.

When all is done it should look some what like this.

And work like this.

The red LED shows when the capacitor is loaded and ready to go.

Step 3: There Always Is Some Hot Glue

Now that all the parts are put together it is time to mount everything into the box.

First, chose a place to put the flash. You might need to carve out the box so that it closes well and inconspicuously. Found the right spot? Secure the flash bulb with some hot glue. Get the electronics near by and don’t forget to put some hot glue onto the top of the capacitor. You don’t want to electrocute people! (Way too much paperwork ;o)
Bend the switch a little as to adjust the time the flash goes of, you nether want the inside of the box illuminated nor the unsuspicious opener to get… well… suspicious, as he sees some strange interior.

Have fun and be safe!

P.S.:

A fresh battery will power the device for about 3 days which is perfectly good enough for me.

P.P.S.: I hope my English is not too bad :o)