Home made T.E.A. lasers

unbelievably simple

[Nyle] was interested in building lasers at home but felt that the exotic parts list was just too daunting. That was, until he discovered T.E.A. lasers. T.E.A. lasers can be constructed from a few bits of aluminum and some high voltage. They emit UV light, as you can see in his examples where he shoots them through a jar full of water with highlighter ink mixed in.

He has posted several variations of different sizes as well as numerous images of them in action. You can see a video of one in action after the break. We also have to point out the fantastic music in the video. It reminds us of those school videos left over from the 50s.

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Building a power supply around a DC-DC converter

The EEVblog is on a roll with interesting topics lately. In the latest episode [Dave] takes us through the nitty-gritty of switch mode power supply design. Using DC-DC converter IC’s in not especially hard. The datasheets tend to have fairly good usage schematics but there’s always a bit of heartache that goes into figuring out which external components will make for an optimal design. Get your calculator out and, in the video after the break, he’ll walk you through choosing component values based on the formulas for the MC34063 converter chip.

[Dave] makes the point that this is an extremely common chip, available from several manufacturers, and often found in consumer electronics. In fact, the switchmode supply hack from last month was using a regulator based around the MC34063. So you can buy it or scavenge for it. One thing to note though, we checked Mouser and Digikey and they’re pretty short on these chips right now. Plan your projects accordingly.

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Small CNC gadget draws what it hears

This art piece makes drawings based on sound. [Mario Marchese], who is responsible for those illusion props back in february, built this little guy out of a bunch of junk he had lying around. It features four microphones that listen to ambient sound and feed the signal through some LM386 audio power amplifiers. The output is translated into forward, backward, left, and right movements of the writing platform while the pen is fixed in the same position. Despite what we said in the title of the post this isn’t strictly a CNC machine, but more the primordial cousin of one.