For what it's worth, here's my plans to build a rather lo-power, lo-cost version:

Preparation:

  1. Find an old, flash-capable, disposable camera.

  2. Also locate a cheap plastic flashlight that runs on 2 AAs.

  3. Acquire them.

Phase 2: Camera Component Extraction:

  1. Strip casing/wrapping off of camera.

  2. Locate the flash capacitor (It's roughly the size of an AA/AAA battery).

  3. Using a screwdriver with a plastic handle, discharge the capacitor by touching the terminals (The two metal wires sticking out one end of the capacitor.

  4. Clip out capacitor with wire cutters.

Phase 3: Preparation of the Holy Vessel of Rapture:

  1. Remove lens assembly from flashlight.

  2. Create the following circuit:

            +----------o   (Shock Terminals)     o-------------+

            |                                                                            |

           +-----------------------------------------------------+(Hooks into switch... bloody ASCII.)

    (Capacitor)--------------------------------------(3-Way Switch)

            |                                                                            |

            |                                                                            |

            +-------------------(Battery)-----------------------+

All those little important bits:

  1. Charge the capacitor from the battery.

  2. Switch circuit paths so the battery doesn't try to drain itself by continually 'topping off' the capacitor.

  3. Discharge the capacitor safely, so you don't zap yourself after you KO your would-be mugger.

Finally, attach something strong and conductive to act as prods (I find that small paper clips work well).

Charge up and have fun!

I disavow any usage of this device for defensive or criminal purposes. Don't drink and zap. You never heard of me. Your Ad Here.