Repurpose an Old CRT Computer Monitor as a High Voltage Science Project Power Supply

High Voltage Monitor Power Supply Conversion

Finally somebody has found a good use for all those old CRT computer monitors finding their way to the landfills. [Steven Dufresne] from Rimstar.org steps us through a very simple conversion of a CRT computer monitor into a high-voltage power supply. Sure you can make a few small sparks but this conversion is also useful for many science projects. [Steve] uses the monitor power supply to demonstrate powering an ionocraft in his video, a classic science experiment using high voltage.

The conversion is just as simple as you would think. You need to safely discharge the TV tube, cut the cup off the high voltage anode cable and reroute it to a mounting bracket outside the monitor. The system needs to be earth grounded so [Steve] connects up a couple of ground cables. One ground cable for the project and one for a safety discharge rod. It’s really that simple and once wired up to a science project you have 25kV volts at your disposal by simply turning on the monitor. You don’t want to produce a lot of large sparks with this conversion because it will destroy the parts inside the monitor. The 240K Ohm 2 watt resistor [Steve] added will help keep those discharges to a minimum and protect the monitor from being destroyed.

Yes this is dangerous but when you’re working with high-voltage science experiments danger is something you deal with correctly. This isn’t the safest way to get high-voltage but if you have to hack something together for a project this will get you there and [Steve] is quite cautious including warning people of the dangers and how to safely discharge your experiment and the power supply after every use. This isn’t the first high-voltage power supply that [Steve] has constructed; we featured his home-built 30kV power supply in the past, which is a more conventional way to build a HV power supply using a doubler or tripler circuit. Join us after the break to watch the video.

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DIY Calligraphy Nibs Get Down to Brass Tacks

diy calligraphy nibsCalligraphy is a rewarding hobby that is fairly inexpensive to get in to. For someone just starting out, poster nibs are a great way to practice making letterforms without worrying about applying the proper pressure required to use nibs that split. With a few tools, you can even make your own poster nibs like [advicevice] does in this Instructable.

Poster nibs are typically made with a single piece of brass that’s folded at the point where the nib touches the paper. The backside forms a reservoir that holds the ink. The other end is formed into a semicircular shank that is inserted into a nib holder. The nibs that [advicevice] made consist of two pieces of flat brass stock plus a section of brass tubing for the shank of the nib. One side of the nib is slightly thinner than the other to act as a reservoir. This keeps ink clinging to the nib through the magic of surface tension.

Nib construction is fairly simple. [advicevice] cut the brass stock to the desired length and width, cut notches with a  jeweler’s saw  to allow the ink to flow, and cut a piece of tubing that holds the nib snugly. He recommends using three grades of sandpaper on the edges of the brass stock and tubing. After soldering the nib to the shank, he beveled the business end by rubbing it on 150-grit sandpaper. He followed this with 350- and 600-grit papers to avoid injury and tearing the paper when writing.

If you simply must spend more money, build a machine that writes calligraphy for you.

 

 

Candle Powered Fan Keeps You Cool Using a Thermoelectric Generator

This is a great example of using a thermoelectric generator for a project. [Joohansson] made both a functional, and aesthetically beautiful fan using components from a computer.

Thermoelectric generators (TEGs for high temperatures, and cheaper TECs for lower temperatures) are also called peltier elements, which look like small square pieces of ceramic with two wires sticking out of them. If you supply power to it, one side will become hot, and the other cold. The TECs [Joohansson] is using want a temperature difference of 68C between either sides. They are typically used for cooling electronics and even some of those cheap mini-fridges will make use of one with a giant heat sink on the hot side.

In addition, they can be used as an electric generator, thanks to the seebeck effect. If you can create a temperature differential between the two sides, you can generate electricity. Using a CPU heatsink, cooler, and fan, [Joohansson] was able to power a small DC fan using only a candle. It’s a brilliant demonstration of the seebeck effect.

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Cheap Under-Cabinet Lights Reimagined as Photography Lighting

diy photography lights

Professional photography lighting can be expensive. Sometimes the professional photographer may not want (or need) to spend the big bucks on lighting. [Alex] is one of those folks. He needed a specialized light source and instead of going out and buying some, he made exactly what he needed out of components unlikely to be found in a photography studio.

The project started off with some off the shelf $12 Home Depot under-cabinet lights. Foam core board was attached to the sides of each light to adjust the beam’s width. Opening and closing these foam flaps allow the light beam to be adjusted to ensure the perfect shot.  The entire assembly was then taped to long, thin pieces of wood. The wood’s sole purpose is to facilitate mounting of the light.

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Designing a Front Panel for a DIY Project

DIY Front Panel

 

When building a one-off DIY project, appearances tend to be the least of our priorities. We just want to get the device working, and crammed into some project case. For those that like to build nicer looking prototypes [JumperOne] came up with a slick method of building a custom front panel for your DIY project.

The first step is to get the dimensions correct. You CAD tool will generate these from your design. [JumperOne] took these measurements into Inkscape, an open source vector graphics tool. Once it’s in Inkscape, the panel can be designed around the controls. This gets printed out and aligned on a plastic enclosure, which allows the holes to be marked and drilled.

With the electronics in place, the front panel gets printed again on a general purpose adhesive sheet. Next up is a piece of cold laminating film, which protects the label. Finally, holes are cut for the controls. Note that the display and LEDs are left covered, which allows the film to diffuse the light. The final result looks good, and can provide all the needed instructions directly on the panel.

[Thanks to Ryan for the tip]

Some Tips About Tips

hackadayTipsaboutTips02

Gather, boys and girls, while we take a moment to talk about submitting projects via the Hackaday Tips Line. Come across something really cool that you think deserves a mention on our page? Let us know about it! Did you yourself make something really cool? Tell us about that, too! It doesn’t matter if it’s a project that’s been sitting on some dark corner of the Internet for a few years. If we haven’t seen it yet, we want to.

Don’t think your project is good enough for Hackaday? You’re probably too self-critical. We’re after hacks: it’s the idea that counts. Not polished? No problem. The only thing that needs to be complete is your description of the hack.

Stick with us after the jump; we’ve got plenty of tips about tips to help you out.

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LEGO® My Single-Phase Induction Motor

[Diato556] made a really cool single-phase induction motor with parts mounted on Duplo blocks. He has posted an Instructable where he uses these modular parts to  demonstrate the motor and the principles of induction as described after the jump.

 

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