How To: Protect Your Door with High Voltage

In this article, I'll show you how to create a simple yet effective way of scaring off intruders. Of course, there are methods around this approach, but it's great for office pranks and general fun. The project requires a little background knowledge in electronics and circuitry, like reading schematics and using a soldering iron. 

Materials and Tools

To build this project, you'll need: 

• A soldering iron
• Flux-core solder
• Insulated magnet wire (copper wire, it can be extracted from a solenoid)
• A disposable camera (Kodak works best)
• Aluminum tape
• Some screwdrivers (depending on the disposable camera screws)

Step 1 Dismantle camera / discharge capacitor

First, dismantle the disposable camera and discharge the capacitor. Using the photo below, locate the large, black battery-like cylinder and cross the two prongs with a screwdriver. This is for safety purposes, since the capacitor can hold a charge for long periods of time and electrocute you if you complete the circuit with your fingers. 

Step 2 Create the circuit

The circuit is quite simple, consisting of the transformer, transistor, resistor, capacitor and diode from the camera circuit. Follow these steps to create the circuit, or use the schematic below (the circuit could easily be made on a protoboard or standalone).

Step 3 Solder capacitor to transformer

Finally, desolder the tiny yellow capacitor from the disposable camera circuit. Then, solder it onto the transformer.

Note: I built my circuit standalone, it looked something like this:

Step 4 Attach magnet wires

Now that the circuit is finished (make sure you install a switch into the circuit!), it should easily operate on the average AA battery, or 1.5 volts. And now you can apply it to your door! The tricky part is getting the victim to complete the circuit with their hand and release the power stored in the capacitor through their hand. Attach two 5-inch pieces of magnet wire to the positive and negative high voltage outputs of your transformer circuit. It's easy to remove the insulation from the magnet wire with a soldering iron, because it just melts off.

Step 5 Place the aluminum tape

Cut some aluminum tape (two tiny 1-inch by 1/8-inch strips) and stick each one on the doorknob, like so:

Note: The picture only shows one side. Also, if your doorknob doesn't look like mine, or is round or another shape, the concept is simply to place the aluminum strips in a place on the handle where the victim would touch both, thus completing the circuit.

Step 6 Attach wires to aluminum strips

Now, take one of the wires you cut earlier and attach it to ONE of the aluminum strips. You can easily attach the wire to the aluminum by bending over a portion of the tape, and wrapping the wire around it. The idea here is to create a "circuit" out of your doorknob, so that when someone attempts to open it, the circuit is completed and electrocutes them. There are many ways to do this, just experiment. :)

Take the OTHER wire and do the same procedure, only to the other aluminum strip.

If you get stuck, or are confused, feel free to contact me or comment.

Step 7 Mount the voltage circuit

Now, mount the voltage circuit on the other side of the door with some tape or similar adhesive. The entire circuit, including the battery, should be very tiny and almost invisible. The wires from the aluminum strips should easily wrap around the door itself, since they are very thin and there is usually some leniency in distance between the door and the door frame.

Step 8 Test it!

Test it out! The voltage from the capacitor isn't lethal (unless seriously misused), but should deliver a startling blast of voltage sure to leave the victim's arms tingling! Most people don't look at a doorknob before they open a door, especially if it's one they go through often. It's better to disguise the silver tape if your doorknob isn't silver—there are many ways to do this. Use your imagination! :)

The circuits used in this article are also used in the High-Lighter Stun Gun and Coil Gun. Check them out if you're interested in other high-voltage projects! 

Warnings

• HIGH VOLTAGE!!!! NEVER work with large amounts of electricity unless you are experienced with safety and the dangers of electricity!
• Soldering irons are hot! Don't burn yourself. 
• Pranking people can result in anger and/or lawsuits! Don't get yourself thrown in jail—use common sense.
• I am not responsible for any damage or harm you cause.