Hackaday Links: October 18, 2012

Capacitive touch plants

Here’s a proof of concept for using plants as a capacitive touch sensor. The sensor is simply a hunk of double-sided copper clad board attached to a microcontroller. But it seems to be able to sense what part of the plant is being touched. [Thanks Fabien]

Adding wireless charging to a Nokia N900

This hack is quite common, but it’s still fun to see what hardware is being outfitted with an inductive charger. This time it’s a Nokia N900 that’s ditching the charging cables.

Wii carrying suitcase from a plastic tackle box

This Wii carrying case (translated) looks great and cost just a few bucks. It started as a tackle box for carrying around your fishing lures. But a bit of creative cutting and there’s a place for everything.

Browser based schematic and board layout

There’s a new kid on the block when it comes to circuit design. Circuits.io offers in-brower schematic design and board artwork layout. [Thanks ADIDAIllinie (and a few others)]

Bender-o-lantern

Halloween rapidly approaches and we hope that [Tim's] carving of Bender in a pumpkin will inspire you to send in your own Halloween projects.

Singing pumpkins

This Halloween table will sing a sweet serenade to spook your guests. Each of the animatronic pumpkins were quite easy to build, but you may end up spending a bit more time choreographing the performance.

Inside each Jack-o-lantern you’ll find a custom Arduino compatible board called a Minion board. These include a wireless connection which lets the system sync with the computer playing the audio. The pumpkins are fake, which means that can be reused year after year (unlike our LED matrix inside a real pumpkin). The mouth is connected to a servo with a short piece of bent wire, allowing it to flap along with the words of a song. You can see a performance of the Ghostbusters theme in the clip after the break.

A custom GUI was written in C# to aid in the choreography. It handles the playback of the song, with a few buttons that can be used to record the light and mouth effects. This ‘recording’ is then used to drive the pumpkins during a performance.

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Candy chucker – weapon, or advanced Halloween delivery system?

Now we know why kids in this neighborhood wear plastic Halloween masks instead of just painting their faces. They’re trying to protect themselves from the onslaught of hard candy spewing out the front of this candy chucking pumpkin.

The mechanism operates very much like a baseball or football throwing device. Now that we think of it, it’s also the same concept as the chicken launcher. There is a feed shoot that drops the projectile into the grips of two spinning chuckers. Those chuckers are built out of a couple of fans, with layers of fabric to account for different sizes and shapes of candy.

The video after the break shows some test firing. We love the sickening ‘whap!’ that the Werther’s Original (or whatever crappy Halloween offering they’re using) makes when it slams into the wall of the room.

This thing’s just begging to be mounted on a parade float, don’t you think?

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Halloween Props: Pumpkin battery

This one would make a nice centerpiece for your Halloween party. It’s a battery with tiny pumpkins serving as the cells. [EM Daniels] shows us how to clear out the pumpkins, fill them with some freshly mixed electrolyte, and he even throws in the directions for baking the pumpkin seeds.

Each pumpkin will need a pair of conductors made of dissimilar metals to serve as the anode and cathode. Copper wire is used for one, aluminum for the other, and both wires have a spiral pattern bent on one end to increase the surface area that contacts the electrolytic solution. Now just boil up a slurry of vinegar, gelatin, and salt, then let it sit in the fridge over night. [EM Daniels] was able get 1.5V out of this project (enough to light one LED) for two hours, and 1.4V for six hours by using seven of the pumpkin cells in series.

[Thanks Karen]

70 LED matrix in a Jack-o-lantern

What takes eight hours to solder and uses more shrink tubing that you thought imaginable? An LED matrix installed in a real pumpkin. When I mentioned that we’d like the LED pumpkin in last Friday’s post scaled up to a full LED matrix I had no idea it would be me doing the work. But [Caleb] and I thought it might be just the thing to present for the hacker’s favorite holiday.

Installed in the autumn vegetable is a marquee made from a 5×14 matrix of light emitting diodes. I spaced them by printing out a grid on the computer, taping it to the pumpkin, and drilling 70 holes in the front of the thing. The real trouble came when inserting all of the LEDs from the inside; each of them has four wires soldered to it, creating a net of black wiring. Above you can see it turned out great. This is a shot of it scrolling the message HAPPY HALLOWEEN.

Join us after the break for video of this prop. But we’re not just sharing the finished product. I’ll take you through the build process. Along the way you’ll learn the design considerations that go into an LED matrix and how you can use these techniques to build your own in any size and configuration you desire.

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Halloween props: Pumpkin in standby-mode

Evil Mad Scientist Laboratories is preparing for Halloween with this standby-mode pumpkin. Inside there’s an LED plugging a hole that is drilled just to the skin of the gourd-like vegetable. It fades in and out similar to a sleeping Mac, using what we think is a vastly over-powered circuit based on an ATtiny2313 (1k  of programming space for this?). But we still like the idea and we’d enjoy seeing it scaled up to a full LED matrix.

We’ve come to expect pumpkin hacks from EMSL and they don’t disappoint. Last year was a mechanized version, and the year before an LED schematic symbol. So what about your creation? With about one week left, take a look around and see if you can’t create something as wonderful as the Pie of Sauron.

Halloween props: Techy Jack-o-lanterns

Halloween is this weekend. If you still have some time and parts available, you might be looking to spice up your Jack-o-lantern.  We’ve found a few projects that we thought might be nice to share. None of them would merit a post on their own, so we thought we would just round them up and share them all at once. They all appear to be powered by the Arduino, which we know will bring some comments. Just to clear up some questions, they don’t pay us to advertise Arduinos. People just do a lot of projects with them.

First, the silly string shooting Jack-o-lantern which you can see above. He’s using a single servo hooked to an Arduino and a motion sensor.  When it detects motion, it lets out a short squirt of silly string. You can download the code from the project page. We might suggest you arrange this in a manner to avoid spraying directly into some kids eyes.

Check out the next two after the break.

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