A Huge Microwave-powered Bug Zapper

August 17, 2012 by Mike Szczys 68 Comments

This is the biggest bug zapper we’ve ever seen. It’s called the Megazap as its zapping area is 1 square meter. [Eighdot] and [Sa007] combined their talents for the build in order to help reduce the insect population around the Eth0 2012 Summer festival.

You may recall from our bug zapping light saber build that these devices work by providing two energized grids. When an insect flies between the grids it allows the potential energy to overcome the air resistance by travelling through the insect’s body. The Megazap uses a transformer from a microwave oven to source that potential. The transformer produces 2.4 kV and the current is limited by a floodlight fitted inside the microwave. The side effect of using the lamp as a limiter is that it lights up with each bug zapped, providing a bit of a light show. Don’t miss the video after the break to see some flying foes get the life shocked out of them.

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Smelting Metal In Your Microwave Oven

December 19, 2011 by Mike Szczys 39 Comments

Grab some scrap metal and a microwave oven and you’ll be casting your own metal parts in no time. [Mikeasaurus], who is known for doing strange things like making Silly Putty magnetic or building his own spray paint bottles, doesn’t disappoint this time around. He read about microwave smelting in Popular Science and is giving it a shot himself.

The image above shows him pouring an ingot. He build an insulated brick enclosure inside of the microwave oven, then set it to go ten minutes for a 50/50 lead/tin mixture, or fifteen minutes for silver. This will vary based on the power rating of your microwave. You can see in the video after the break that the setup gave him some trouble shortly after pouring. It wasn’t a problem with the molten metal, but spontaneous combustion of the rigid foam insulation that did him in. We shouldn’t say ‘I told you so’, but that insulation says right on it that it’s flammable!

This isn’t the first time we’ve looked at casting metal melted in a microwave. Check out this other version posted back in 2005. Continue reading “Smelting Metal In Your Microwave Oven” →

3-phase Jacob’s Ladder

April 15, 2011 by Mike Szczys 18 Comments

Two sparks are better than one, a sentiment that was never more blindingly illustrated than with this three-conductor Jacob’s Ladder. The build centers around three-phase power, which uses a trio of alternating current sources sharing the same frequency, but offset by 1/3 from one another. If we’re reading the schematic correctly, [Jimmy Proton] is using normal mains as a power source, then connecting three transformers and a capacitor to set up the different phases. Two of the transformers, which were pulled from microwave ovens, are wired in antiparallel, with their cores connected to each other. The third transform is connected in series on one leg of the circuit.

The video after the break starts with the satisfying hum of power, only to be outdone by the wild sparks that traverse the air gap between conductors of the ladder. After seeing the first demonstration we kind of expected something to start on fire but it looks like all is well. We’ll probably stick to a less complicated version of Jacob’s Ladder.

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