High Voltage Thor’s Hammer: Mjolnir At 80,000 Volts

[Thor’s] hammer, Mjolnir, is pretty freaking awesome. It can only be picked up by [Thor], he can use it to fly, and probably the coolest part, it can summon lightning. After watching the first movie, and goofing around with the guys at ArcAttack, I had this idea that I could stuff a tiny tesla coil into a mjolnir and end up with a really cool prop.

At this point, I had to make a decision. I was either going to go portable and live with small arcs, or make this a stationary piece and hide a giant tesla coil in a base. It would have bigger arcs, but I couldn’t carry it around.  While I may re-visit the stationary version at some point, I ultimately decided I wanted to be able to wander around and play with this thing.

I had seen some videos of [Staci Elaan] showing off her battery-powered coils and I really liked her results. I figured, with her experience, she could probably do a better job than I could on getting the most bang out of a small package.  She was happy to be involved and delivered a small 12v powered coil for me to work with. I should also point out that the coils [Staci] makes are usually donated to educational groups. This woman is awesome.

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AM Tube Radio Restored And Given MP3 Playback Too

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This AM radio looks a bit like it did coming out of the factory. But there are a lot of changes under the hood and that faceplate is a completely new addition. The project really is a restoration with some augmentation and [Michael Ross] did a great job of documenting the project.

The Kenyon radio was built in 1946 and uses vacuum tubes for the amplifier. Considering its age this was in relatively good shape and the first thing that [Michael] set out to do was to get the electronics working again. It involved replacing the messy collection of capacitors inside. He then cleaned up the tubes, checking for any problems, and put the electronics back together to find they work great!

He cleaned up the chassis and gave it a new coat of finish. The original dial plate was missing so he built a wood frame to match a dial scale he ordered. The bell-shaped brass cover hides the light that illuminates the dial.

He could have stopped there but how much do people really listen to AM radio these days? To make sure he would actually use the thing he added an Arduino with an MP3 shield. It patches into the antenna port via a relay, injecting modern tunes into the old amplifier circuit. Catch a glimpse of the final project in the video after the break.

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DIY Laser Cutter Built To Make Stencils

It was time for some new T-shirts so [Andreas Hölldorfer] built a laser cutter. Wait, what? That’s the excuse he’s going with, and in the end this scratch built laser cutter did come in handy by cutting stencils to use when decorating his garments.

The first thing we thought when looking at the cutter is where’s the tube? [Andreas] didn’t use a CO2 laser, so this ends up being rather low-powered. The cutting head is a 1W blue laser diode which manages to slice the three-ring binder separator pages he’s using for the stencils. The two-axis machine is mounted inside a wooden box to protect his eyes while it’s cutting. He plans to add a drawer later on so that the cutting bed will slide in and out to swap out material for the next project. He already does a lot of 3D printing work and had an old RepRap driver board on hand to use for this projects. He designed and printed the red mounting brackets which make all of the junk-bin components work together. Not bad!

If you’d like to try this out on a smaller scale try using optical drive parts for the axes.

Life Meter Gives A Real Life Measure Of Video Game Health

water-light-health-bar

This hack makes the virtual real by displaying your video game character’s health meter as a column of illuminated water.

The build video, which you’ll find embedded after the break, is really quite remarkable. The column is a clear piece of pipe anchored at one end by hand-tightened plumbing drain fittings. This allows [Bfayer] to attach a flexible bladder which he constructed for the project. An actuator pushes a hinged board up against the bladder to raise and lower the water level in the tube.

Alone that’s pretty impressive, but [Bfayer] went the extra mile and then some. He uses a four-way fitting at the bottom of the meter. One fork connects to the bladder, another allows air to be injected using an aquarium pump. The bottom of the fitting has a clear window so that an RGB LED array can shine into the water which was doped with highlighter ink to pick up the colored glow. To pull the whole thing together he coded the custom control interface seen above.

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Bluetooth Stepper Motor Driver

bluetooth-stepper-motor-driver

[Dan] salvaged some parts from an old printer a while back and finally found some time to play with them. One of the things he was most interested in is the geared stepper motor seen above. He was able to get it running with an Arduino in no time so he decided to take the project a little bit further. What he ended up with is a stepper motor driver which can be controlled over Bluetooth.

The motor can’t be driven directly, but with a simple motor driver like the L293 chip [Dan] used it’s not hard to interface them with your control hardware of choice. From there he added an ATtiny85 which will take care of the stepping protocol necessary to move the motor. The Bluetooth module he’s using functions as a serial device, making it really simple to interface with the uC. [Dan] uses a pin header to connect the module, so switching to a different type of serial device in the future will be quick and painless.

After the break you can see him sending step commands to the driver board.

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