http://www.youtube.com/watch?v=Nnjh-zp6pP4So anyway, a gaming mate asked be to have a think about building a static grass applicator. Model train people have been using them for ages – you apply a static charge to the grass, and when you sprinkle it out onto the glue, it stands up.

Cool. So I built this voltage multiplier:

And you know what? It works great. I plugged that sucker into household 240v attached on end to some paper streamers and the other end to a wire on the end of a long stick, and blow me down if the paper didn’t move around when I bought the other wire anywhere near it.

(I put on clean underwear before testing it, and left my front door unlocked in case I needed to be taken to the hospital.)

Nice fat spark when I discharged it, too, after turning it off.

But darn it, my mate is not keen on anything I build being plugged into 240v at his home. He has a case, although it wasn’t me who nearly burned his place down last time we built something there. Just saying.

So, I need to drive it off a battery. The power needs to ripple, so I need some sort of oscillator. Been trying to build me a multivibrator (it’s what they are called, or as Katy Gallagher would say, it’s a word that people use).

Not having a lot of luck. Electronics is trickier than computing. Well, unless you are doing comms or UI, obviously. I’ll wander over to MHV Tuesday or Wednesday. Someone will be there to chuckle condescendingly at my naïvety and possibly get the thing going.

Should be cool.

3 Responses to Voltage

  1. Paranoid gaming mate says:

    Interesting link – seems to be the same voltage pump circuit as used in the first particle accelerator and nuclear program… (!)

    Given you’ve tested it and not died, that makes me a little more comfortable about trying it… 🙂 but the live bits and joints must be insulated properly…

    Found a relevant warning about these things:

    Note that some safety margin is needed across the relative range of voltage differences in the multiplier, so that the ladder can survive the shorted failure of at least one diode or capacitor component. Otherwise a single-point shorting failure could successively over-voltage and destroy each next component in the multiplier, potentially destroying the entire multiplier chain.

    • Paul Murray says:

      Destroying the unit isn’t a big worry – the worry is possibly shorting out mains to the bit you hold. I’ll see how I go on tuesday. If I can’t get an oscillator working, I’ll drive it off mains through a voltage-reduction transformer.

      I have the sieve part of the unit built. It’s – ugly looking. Hot-melt glue all over the place. Might be simpler to just use a stainless steel sieve as-is.

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