Making a Flashy Trap Box

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!


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)



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    8 Discussions


    8 years ago on Step 3

    Hehe! Willy's got me on the project, too! I've been tech-ing for years, and I'm seeing the ways that these ideas should shape out, can't wait to try them :-) Tell me, though, what size battery should I use for this? Is the camera's battery labelled for size and voltage/amperage? I don't wanna burn out the filament in the flash (believe me, this is gonna get -SO- many uses!), and a flash is kinda all I want. No sparks or fires :-) And I'm seeing room for a battery disconnect (on/off switch). Would you advise that, though?

    1 reply

    Reply 8 years ago on Step 3

    The battery is a simple 1.5V AA battery. If you want to be able to cout the cirquit and have enough room for it, feel free to throw in an on/off switch. For me getting flashed while opening the box and just taking out the batery is enough comfort :o)


    8 years ago on Step 3

    I know that this was posted awhile ago, but do you have any ideas for a pressure plate or trip wire version?

    2 replies

    Reply 8 years ago on Step 3

    For a pressure plate version I would use the same switch but soldered in a way, that it closes the cirquit on "push" and I would ad springs to hold the plate above the switch. Or perhaps no switch at all but two pieces of sheet metal that come together when someon stepps on the plate. For a trip wire version I would youse a simple "switch" made of a clothes-peg an two drawing-pins. The cirquit would be open as long as a piece of plastic, atatched to a string, is between the pins. Pulled out by the "victim" the two pins touch each other and close the cirquit. I hope what I said was helpfull and understandable. If you have further questions feel free to ask :o)


    Reply 8 years ago on Step 3

    oh very much so! thank you so much! yeah I saw your box and was like WOW I can use this for trap ideas of my own. Thank you as well for the fast reply i'm used to having to wait days for a response...