## High Voltage: Build your own 84 kV lightning stick

There’s a proverb that says ‘Speak softly and carry a big stick’. Now that stick can come in a high-voltage form factor. The device above, which reminds us of a side-handled baton with a coke can stuck on the end, is a portable Van de Graaff generator.

Although debated in the comments, the creator of this hack claims you can shock someone with 84 kV of electricity using the device. Of course as a weapon it’s lacking since we’re talking about static electricity; the voltage can be through the roof but the current is extremely low. Despite that, there are some fun things you can do with them. The video after the break show it throwing off sparks with the lights dimmed. [Yardleydobon] also includes a few other tricks at the end of his tutorial. He makes a set of Franklin Bells using two more soda cans with the aluminum tab from one suspended in between them. As he charges it up, the tab dances back and forth, ringing the ‘bells’ it runs into. Once they are charged, the ringing can be restarted by discharging just one of the cans.

## Turning beer cans into bells with 35kV

It looks like we now have another way to annoy ourselves with extremely high voltage.

The bells operate under the same principles as the electrostatic see-saw we covered last month. A voltage is applied to one can while the other can is grounded. An insulated pendulum is placed between each can, and with a little coaxing can be made to oscillate back and forth between the cans. As the pendulum touches the charged can, it is repelled as it gains the charge and moves to the grounded can. There, the charge is released and the cycle continues again. A homemade Cockcroft Walton multiplier is used to generate the +35kV needed to get the pendulum moving.

[Ben Franklin] invented the Franklin Bells while he was investigating electricity in the 1750s. Originally an extension of the kite & key experiment, the bells were historically used to warn of approaching thunderstorms – when the bells rang, the atmosphere was charged and lightning could strike. Even though the voltage between the bells is huge, very little current is drawn – the Oxford Electric Bells have been ringing since 1840 using the same electrostatic battery.