Make Your Own Solenoids, Then Play The Xylophone

December 2, 2010 by 25 Comments

Learn to manufacture your own solenoids and then use them to play the xylophone by watching the tutorial video after the break. [Humberto Evans] and the team at Nerd Kits do a great job of not only manufacturing the coils, but the xylophone itself. The bars are machined from some aluminum stock and they take you down the rabbit hole with they why’s and how’s of engineering the keys.

We’re unlikely to replicate this machining process but the solenoids are another story all together. Starting at about 3:30 you can learn about designing, building, and using these little marvels. They’re basically an electromagnetic cuff with a metal slug in the middle. The solenoid seen above uses a body milled from HDPE and wrapped with magnet wire. The slug in the center is steel, with a few rare-earth magnets at the top. When you run current through the coil it repulses the magnets on the slug, witch then strikes the xylophone key. Using a MOSFET and a protection diode, actuating them is as simple as sending a digital high from your microcontroller of choice.

We’ve seen solenoids used to play a vibrophone before, but those were commercial units. Making your own hardware is far more hardcore.

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Heater For Bending Acrylic

December 2, 2010 by 22 Comments

We like using acrylic in our projects but there are a couple of tricky techniques, particularly getting clean cuts for glued edges and bending the material into curves. [Giorgos Lazaridis] has a great solution to the latter, a dedicated acrylic heater. Instead of using an oven to warm the material for bending he’s using localized heat produced by a high-powered lamp pulled from an old laser printer. The next part of his solution is to keep the heated area of the acrylic as small as possible. This was achieved by creating heat sinks on either side of the bulb. The metal bars seen above have water running through them to help isolate the softening of the material to a narrow strip. See how well this system works in the video after the break.

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Steam-powered Rickrolling

December 2, 2010 by 28 Comments

This is a steam-powered record player; awesome. But wait, that’s not all. Watch the video after the break for about two and a half minutes and you’ll realize that it’s also a Rickroll. No, you’re not getting baited into clicking through to Rick Astley’s music video, the LP that’s playing on the turntable is a copy of “Never Gonna Give You Up”; all kinds of awesome.

This all started with a steam engine machined from a stainless steel bolt and a brass cylinder. It was tested using compressed air before building the boiler. But what’s a steam engine without a purpose? The problem with using a steam engine as a turntable motor is speed control. This is where we move to modern technology, using an Arduino to measure the RPM and adjust the steam engine using a servo motor.

The builder makes a comment that this sounds terrible, but considering it’s steam-powered we think it sounds just fine.

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J1: A Small, Fast, CPU Core For FPGA

December 1, 2010 by 25 Comments

[James Bowman] of the Willow Garage published a paper on his J1 CPU core for field-programmable gate arrays. This was originally developed and used for the Ethernet cameras on the PR2 (you know, that incredibly expensive beer delivery system?) robot. It uses a 16-bit von Neumann architecture and lacks several processor features you’d expect a CPU to have such as interrupts, multiply and divide, a condition register, and a carry flag. None-the-less, its compact at just 200 lines of Verilog and it can run at 80 MHz. [James] compares the J1 to three different FPGA CPU Cores commonly used and discusses how the system is built in his 4-page paper that has the details you’re interested in but won’t take all day to dig through.

You Know That They Say About Guys With Big Lenses?

December 1, 2010 by 35 Comments

[Tony Lovell] and [dkpeterborough] built a sizable camera lens using optics from a flight simulator projector. What they ended up with is a 900mm lens that can make a beautiful photo of the moon, or capture distant landscapes in great detail. The body of the lens was designed in CAD and sent off for fabrication out of aluminum, as seen above. The concentric baffles help to prevent lens flare but it can’t be used in its bare-aluminum condition. The internals were coated using a stippling finish that leaves a sandy texture. That was covered with matte black barbecue paint, doing a great job of preventing optical interference, and the outside received a glossy white coat. Finished weight: 59 pounds, but once you see the pictures you’ll agree it’s worth lugging the bulky instrument around to grab that killer shot.

[via Make]

Developing An Animatronics Platform

December 1, 2010 by 10 Comments

This Predator costume has an animatronic element in the shoulder cannon. It tracks the movement of the mask, aiming wherever the Predator gazes. [Jerome Kelty] was asked by a friend to help develop the costume and he ended up with an animatronics platform which can be adapted for many different uses.

Starting with an Arduino Pro Mini [Jerome] designed a host board which would breakout the pins of the Arduino and make it easy to connect and drive multiple servo motors. The board is powered by a 3.3v Lithium Polymer battery with charging handled by a MAX1555 that was included in the design. Check out the video after the break which shows off the Predator suit. Looks like [Jerome] got it right, and he’s also put the platform to use with an Ironman suit that has an arm-mounted missle feature.

Need some inspiration for you next costume build? Take a look at this animatronic collection to get you started.

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Fake Christmas Tree Makes It Fake Snow

December 1, 2010 by 23 Comments

Let it snow inside your house this Christmas by building your own snow making tree. [Trey] was inspired by a snowing lamp-post he came across in a story. He looked around the house and came up with all the stuff necessary to make this happen with a Christmas tree. The snow is loose Styrofoam like you’d find in a bean bag chair. At the bottom of the tree there’s an inverted umbrella to collect the snowfall and funnel it into a blower salvaged from an inflatable Halloween yard ornament. The blower shoots the Styrofoam up through a PVC pipe, which also serves as the trunk of the fake tree, and it erupts from the top bringing Christmas cheer to an otherwise quiet room. See for yourself.