OnshouldersTV Knows How To Use OpenSCAD

June 3, 2011 by Gerrit Coetzee 7 Comments

Recently there’s been a increase in the popularity of OpenSCAD as the tool of choice in the 3d printing community. [Gavilan Steinman] is putting out a series of webTV shorts on the use of OpenSCAD. While it lacks a lot of the features of big CAD suits (such as the ability to generate drawings of your parts), the community has proven it’s effectiveness as a design tool. There are only two episodes out so far but they cover OpenSCAD, mathcast, 3d printing, and a really neat robot design. Watch them below.

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Trick Mouse Keeps The Screen Saver At Bay

June 2, 2011 by Mike Nathan 94 Comments

mouse_wiggler

[Jerry] wrote in to share a little device he built to solve a problem he was having at work. You see, every computer in his office has a policy-enforced idle timeout, requiring the user to enter a password in order to regain access to their desktop.

This is a huge pain, since he sporadically uses an old computer for the sole purpose of monitoring some applications running in his data center. With the computer timing out every 10 minutes, he is constantly required to enter his password in order to take a 10 second glance at the screen to ensure everything is OK.

Rather than circumvent the screen saver using a local security policy or by implementing a microcontroller-based signal generator, he opted to create a mechanical solution instead. His computer’s optical mouse resides inside a wooden frame, and is periodically swept from side to side by an ATmega-controlled servo, keeping the screensaver permanently at bay.

Call it a hack, call it a kludge, call it what you will. All we know is that while we might have done it a little differently, it works just fine for [Jerry], and it generates all sorts of interesting conversation to boot.

Stick around for a quick video demonstration of his mouse wiggler box.

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Buying, Selling, And Bartering Hacking Hardware

June 1, 2011 by Mike Szczys 5 Comments

Regular reader [Grenadier] wrote in to let us know about his newly published hacking hardware trading post called The Junkbox. Apparently when he’s not blowing up capacitors or building his own high voltage ones, he makes time to code up a website where you can buy, sell, and barter leftover components.

We have something like this right here at Hackaday. The dollar sign icon along the right column, just underneath the featured posts banner will take you to our classifieds section which at the time of writing had a whopping nine items posts. But these things to ebb and flow. Check in on the newly posted link from time to time to see that number grow.

Whether it’s over at The Junkbox or in our classifieds section, we think the biggest problem is finding what you need when you need it. This is nothing new. If you missed it before, we’ve embedded an older episode of the EEVblog after the break where [Dave Jones] tours Apex Surplus. It’s as if a hacker who has hoarding tendencies bought a store forty years ago and just kept piling more and more merchandise to the sky.

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Devil Horns Adorn The Hood Of My Truck

June 1, 2011 by Mike Szczys 31 Comments

When you’re hunting zombies you’ve got to give them something to fear. [Shannon Larratt] is getting ready for that eventuality by adding devil horns as his hood ornament. It looks awesome from afar, but when you see the close-up images you realize how lifelike this is. That’s because it’s not a sculpture. [Shannon] cast the ornament in a mold made from his own hand.

The process started with some dental alginate which he slobbered all over his hand as he held the devil horns pose. After the mold had hardened he cast the ornament using fast-curing black plastic resin.

With the ornament now in hand he needed a way to secure it to the hood of his vehicle. He picked up a threaded U-bolt. A hole and a slot were carved in the base of the ornament to receive the U-bold and a straight bolt for a trio of anchor points. More of the black resin fills the holes, securing the bolts and making it a snap to mount the ornament by drilling through the hood.

We also find it awesome that during this process [Shannon] took the time to cast his daughter’s fist for use as a door knob at home.

Automated Hose Keeps Cats From Watering You

May 25, 2011 by Jesse Congdon 50 Comments

Commenter [TheCreator] reminded us of this fantastic video from [Craig Turner] who you may recognize from SBS’s Top Gear Australia Video Competition. You see, [Craig] has been struggling for some time with the problem of neighborhood cats relieving themselves pretty much all over his stuff. Through surveillance he identified (and named) around 9 separate cats sauntering into his yard during the wee hours of the night. The only issue now was to humanely discourage them from entering his yard.

The best solution, in this case, was a simple spray from the garden hose, but who is going to stay up all night to watch for cats? [Craig]’s ’75 Galant happens to have aftermarket door locks. These typically contain a simple powerful 12V actuator that will push or pull when given current. The actuator is strong enough, and has enough travel, to depress your typical garden sprayer handle. The lock actuators even include enough mounting hardware to tack everything together. The only irreversible part of the hack appears to be the hole drilled into the sprayer’s handle.

The job of cat detection is handled with a PIR sensor (sourced from his home security system) and a paper towel tube to narrow the detector’s field of view. Placed at animal height the PIR detector works like a trip line, and flips a relay connected to an array of devices: A bright LED lamp, a DSLR set to take several quick photos of the victim, An HD video camera, and the sprayer solenoid. This whole rig is placed at a convenient choke point and hilarity ensues! A schematic is included in the video but is pretty difficult to interpret, we transcribed it for you. Some details are unclear but essentially a few relays are stapled together to provide either high or low switching signals.

Check out the video, [Craig]’s schematic, and our interpretation of [Craig]’s schematic after the jump!

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Hand-cranked Magnet Machine Is Endless Fun

May 25, 2011 by Mike Nathan 41 Comments

magnet_machine

We can’t think of a single person who doesn’t enjoy playing with a handful of rare earth magnets now and again. We know that [Dave Johnson] certainly does. As a gift to his father in law, he constructed a magnificent machine that does little more than manipulate spherical rare earth magnets with hypnotizing grace.

The machine is constructed almost entirely from wood, save for a few fasteners and rods. Even the gears have been carefully cut from wood, with special attention paid to ensure smooth operation. When cranked, the machine slices off a single magnet from one end of a long chain, passing it along to a lift arm. The lift arm deposits the magnet into a metal tube, and with the help of eddy currents, it drifts slowly down before being redeposited at the end of the magnet chain.

Be sure to check out a video demonstration of the machine after the break, it really is fun to watch.

[via LaughingSquid]

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Building A Brushless Motor Controller

May 24, 2011 by Mike Nathan 12 Comments

brushless_motor_controller

Brushless motors and the way in which they are controlled can be a bit of an enigma to those just starting out in hobby electronics. [Andrew] from spingarage thought it would be helpful to put together a quick tutorial showing how he built a simple brushless motor controller in about a day’s time. He constructs everything on protoboard from components he acquired at RadioShack in order to demonstrate the ease of sourcing parts and building a brushless motor driver.

While he skips most of the theory behind brushless motor control itself, he does touch on the signaling these motors require for movement as well as how motor position is determined. Specifically, he expands on how half-bridges can be used to create the sine wave signaling required by a single motor input, as well as how three of these can be combined to drive a brushless motor.

The post is the first in a series of posts about brushless motors, so we should see some code examples and some practical applications in the near future.