Cooking Up Piezo Crystals At Home

March 15, 2011 by Mike Nathan 56 Comments

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[Collin] loves piezos – and why not?

According to him, they are about as close to magic as you can find in the world. We can’t really disagree on that one – there’s something oddly enchanting about piezoelectric materials.

Most commercially used piezoelectric devices that you find today are constructed out of man-made ceramic materials such as Lead zirconate titanate, and can be found in grill starters, gas-powered water heaters, etc. While they are common, it’s not exactly easy to synthesize these sorts of ceramic materials at home.

You can however, create piezoelectric crystals in your kitchen, using just a few simple ingredients. In his video, [Collin] shows us how to create Rochelle Salt, one of the first known materials found to exhibit piezoelectricity. The recipe calls for three ingredients, cream of tartar, sodium carbonate (soda ash), and water – that’s it. The procedure is quite simple, requiring you to heat a solution of water and cream of tartar, adding the soda ash a little at a time once it reaches the proper temperature. The solution is filtered after it turns clear and then left to sit overnight while the crystals form.

Take a look at the video embedded below to see how his Rochelle Crystals turned out, and be sure to try this out with your kids if they are interested in electronics. Making crystals that generate electricity when tapped is far cooler than making rock candy any day, trust us on this.

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Animated Paper

March 15, 2011 by Kevin Dady 8 Comments

What if you could make paper react on physical input. Maybe you want it to shy away and close up if someone reaches for it too fast, or maybe you want some realistic paper flowers? Moving on to that great first step is Animated Paper, which is simply nitinol memory wire bonded to paper via our favorite tool, duct tape.

Memory wire is first bent to its desired shape, and in order for it to hold that shape it needs to be heated to about 540 degrees Celsius, which is a easy task for a propane torch. Once it has its memory shape the wire can be bent into any shape desired, and when heated to about 70 degrees Celsius will return to its original set shape.

Taped down to a sheet of paper and letting some current from a battery run though it the wire quickly warms up and animates the paper, which could be exactly what one needs in a more artsy robot or electronic display. Join us after the break for a short video.

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Personal Soundboard Recounts Years Of Clever One-liners

March 12, 2011 by Mike Nathan 7 Comments

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[Antibore’s] friend was just wrapping up his Ph.D. Degree and he wanted to build him something special to commemorate the accomplishment. After thinking about it awhile, he realized that his friend was quite gregarious and known to make off-the-wall comments at parties and such. A ton of these one-liners were documented on video over a span of 10 years, so [Antibore] got the idea to make his friend a soundboard featuring his own witticisms.

He found a breakout board capable of playing back OGG files and got to work loading it up with his friend’s random sayings. The board was connected to a small amplifier and speaker, then everything was installed into a black plastic case. Four arcade-style buttons were mounted on the front of the case, along with a picture of his friend. Up to 16 different sayings can be played, depending on which combination of buttons are being held at a particular time.

It’s sounds like a really cool project, and certainly makes for a one of a kind gift. Currently there is no video or audio of the box in action, but here’s hoping we’ll see some soon.

DIY Flower Bouquet Guaranteed To Get You Dumped On Valentine’s Day

March 10, 2011 by Mike Nathan 36 Comments

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[Erik] is a broke engineer.

When this past Valentine’s day rolled around he didn’t have any cash to buy a gift for his girlfriend, so he had to get creative. Every girl likes flowers, but unless he was going to give his lady some day old daises from the grocery dumpster, he would have to make them himself.

He started by bundling together and bending some T-shirt hangers into stems. He then wrapped them in the green & green/white wire pairs from some Cat-5 cable to give them some color. An old keyboard was sacrificed to create the flower petals and leaves, which were presumably colored with markers before being glued to the end of the hangers. He added a reed switch to the flower pot, which illuminates the LEDs he installed under the petals when a magnet-bearing cardboard placard reading “Love Erik” was placed near it.

How did his girlfriend like them? Well, let’s just say she’s no longer in the picture. He didn’t tell us if the bouquet was the reason, only that she’s gone. (though we happen to think it’s pretty cool).

Keep reading to see a quick video demonstration of the light-up bouquet.

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Give KiCAD A Try. Here’s How

March 10, 2011 by Mike Szczys 45 Comments

Up to this point we’ve used Eagle CAD as our exclusive PCB design and schematic layout tool. But [Brian] has inspired us to try something different thanks to his KiCAD tutorial.

KiCAD is an open source printed circuit board design tool. Since we like to rock the Linux here at Hackaday getting our hands on this was as easy as:

 sudo apt-get install kicad

The version in the Ubuntu 10.04 repositories is a bit older but seemed to work just fine. [Brian] jumps right in with one of our most dreaded tasks on Eagle, designing your own parts. He knows of a nice online tool for automatic KiCAD part generation and walks through the process of building a voltage regulator and importing it for use in your own personal library From there it’s off to layout a power supply schematic for a breadboard PSU. The lesson continues with board layer, as well as the process used for exporting data for PCB fab house. We think this tutorial works well if you’re already familiar with PCB layout using a different software package but it moves a bit fast if this is your first time.

KiCAD seems like a nice tool and we’ve heard from many advocates in the comments over the years. Look for our next PCB design to be on KiCAD as we just need to use it for a while before passing judgement.

Keyboard Converter 2 Pack

March 10, 2011 by Kevin Dady 14 Comments

[REVENGE] pointed out a couple cool little project posts from the geekhack fourms converting vintage keyboards to USB with a Teensy. They both have VUSB support, so any avr micro controller that meets VUSB’s requirements in theory could be used.

First up is a PS/2 to USB keyboard converter, and while yes this has been done many times before, this one sports some extra features not often seen, like mouse keys, system and multimedia keys, and keymap customization. Instructions are also provided for use with a non USB enabled avr controller (like a mega 168, or 328) through the VUSB library (though with not all features available).

Next is pretty much the same thing, but it converts Apple Desktop Bus to USB, which is not exactly rare, but its lack of a clock serial signal, somewhat variable timing, and the fact that you wont find a bucket of Apple keyboards for a buck at the thrift store makes any ADB converter worth mentioning.

VUSB instructions seem to be the same for either, source is available and there are some cool pictures and info listed, and besides what is more fun than being able to plug your Model M into your netbook, or your Apple Extended Keyboard into your mac mini.

Simple Fluidyne Engine

March 9, 2011 by Mike Szczys 20 Comments

[Mirslav] built this fuidyne engine himself. This is a single piston model but you won’t find any precision milled cylinders here. That’s because fluidyne engines use columns of water as the pistons. In the rig shown above you can see one metal pipe which serves as the cold side of the loop. There’s another hot pipe underneath the insulation that completes the circuit. When that pipe is heated it causes the air inside the loop to expand, forcing the liquid on the open side of the plastic tubing (to the left) to rise. Once that air escapes to the other side of the circuit the water piston in the open tube falls back again. This results in continuous oscillation that can be used to drive a pump using a pair of check valves.

We’ve embedded a couple of videos after the break. You’ll see the system tested by heating one pipe with a hot air gun. But the example seen above uses an induction coil to bring the heat.

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