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The exact gauge of wire isn't that important. If you want thin wire, old hairdryers ( and theres loads about ) will have some. It doesn't need to be coiled up. What's important is to get the current to make it glow hot enough to ignite paper ( red-hot, around 1000 deg ). How? Well, it isn't as trivial as this 'ible implies: you need to do some homework. First get your wire, but you'll need to measure its diameter. Next look up tables on Google of wire gauge vs resistance and temperature vs. current. From the wire length you have the resistance and from the other table, how much current you need. From that you'll need to calculate the sort of voltage required. What you don't do is to start with something as hopeless as a PP3. You need something with balls: I'd use a Li-Ion 18650 or two. To assume that, if you have a PP3 battery ( nominal 9V ) and a 9 ohm piece of wire, you will draw 1 Amp shows this guy hasn't got much of a clue.
I once built an anemometer. IIRC, I had an opto-slot and a segmented disc. No matter. There are many different hardware designs, but all have the same problem: how do you calibrate it?
Nice hacks, but I was disappointed by the rope-shortener hack: I simply cannot understand how it's done and the pics are no help at all. Could you redo them, but get in much closer and make the process clearer. Thanks
You are being crass and narrow-minded. The Imperial system isn't American, it comes from the UK and is centuries old - the USA is only a few hundred years old. The metric system has some advantages and is used in science and technology. I was in research for 40 years and never used anything else. But the Imperial system isn't some haphazard accident: it's a perfectly natural and obvious system which takes account of everyday observations: a man's foot is a convenient measure; a thumb-joint is similar. We then say let there be twelve thumb-joints in a foot and call it one inch. And so on and so on. And base 10 is only special if you happen to like it: base 12 has much going for it, being divisible by 2,3,4, and 6. Before you dismiss something as bollocks, perhaps you should be more aware of its place in History.
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