Making A Solid-state Relay With I2C Interface

November 1, 2013 by 34 Comments

As [Mic] often got requests to make high-power switching boards, he recently finally gave in and designed the one shown above based around a solid-state relay. Some of our readers that already play with mains power know that switching should normally occur when the voltage crosses zero volts. The ‘TRIAC BLOC’ is able to do so, which also allows mains frequency measurement. [Mic] then tuned to the internal oscillator of his ATtiny microcontroller with this 50Hz by adjusting its OSCCAL register value, so the switching command can be sent at the ideal moment. Zero crossing detection is implemented by feeding the mains into an AC optocoupler. [Mic] discovered that the optocoupler diodes are not identical, so he had to adjust his firmware to account for the time differences.

All the resources are available on github, we would be interested to hear your detailed analysis of the circuit implemented with the passives R3/C1/L1/R8/C3.

Hackaday Logo Projector From A Single LED

October 31, 2013 by 11 Comments

Here’s another Trinket Contest entry that was interesting enough for its own feature. [Adam] made his own Hackaday version of the Bat signal. It’s not nearly as big, but the concept is the same. Using this single modified LED he’s able to project a 12″ image that seems quite well-defined (more pictures below).

The LED is one he pulled from an old flashlight. After sanding the dome flat he made a jig which positioned it inside of his laser cutter. From there he etched the 0.1″ logo and filled the negative space with some ink. The remaining surface was polished to help the light shine through, then positioned in front of a jeweler’s loupe to magnify the image.

There’s just a couple of hours left before the Trinket Contest draws to a close. Get your entry in for a chance to win!

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GimBall Bounces Off Trees And Comes Back For More

October 31, 2013 by 22 Comments

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We’ve seen a lot of flying robots over the years, and for many of them, intimate contact with a stationary object would be a very, very bad thing. [The Laboratory of Intelligent Systems], at EPFL in Switzerland designed GimBall to not only take impacts in stride, but to actually use them as navigational aids. This is similar to an insect bouncing off an obstacle in nature.

GimBall’s design is a bit of a departure from the norm as well. Contra-rotating airplane propellers provide thrust while countering torque. It appears that the propellers are driven by two separate brushless outrunner motors, which would allow for yaw control via mismatched torque. Directional control is provided by a 4 articulated vanes on the bottom of the craft. Standard RC servos move the vanes. While not as common as quadcopters today, this “tail sitting” design has been around for decades. The Convair XFY “Pogo” is a good example of an early tail sitter design.

What makes GimBall so novel is its exoskeleton. A carbon fiber gimbal encircles the entire craft. Around the gimbal is a geodesic sphere made up of carbon fiber rods and plastic joints. The sphere acts like a shock absorber, allowing GimBall to harmlessly bounce off objects. The gimbal ensures that impacts won’t upset the craft’s attitude. Check out the video after the break to see how these two systems form an impressive shell which completely separates GimBall’s chassis from the outside world. GimBall can actually use its shell to “rotate” around obstacles.

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Halloween Links: October 30th, 2013

October 31, 2013 by 4 Comments

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Happy Halloween from everyone at Hackaday! To help you enjoy the holiday here are a few festive links:

[Mike Kohn] whipped up a set of motion tracking eyeballs to make his decor extra creepy.

There’s not much to this jet-pack costume but the results are pretty amusing.

The eyes on [Tim Butler’s] skeleton prop don’t follow you around the room, but they do use a PIR sensor to light up the skull.

Speaking of skulls, [Tom] is using some real skulls as decorations. He also added lights where the eyeballs should be, but he is using a photoresistor and comparator to turn on some LEDs.

[Clark] built a Mecha Robot Warrior costume for his son. With all of those LED strips we think he’ll be pretty safe when crossing the street!

And finally, [Jesse] added a lot to his prop in order to produce a Sinister Joker. That’s Joker-as-in-cards and not as in Batman. It’s got an IR distance sensor as a trigger, with a motor to move the wrist, lights for the eyes, and a sound shield to give it a disturbing voice.

Light Controller Goes Overboard For Halloween

October 31, 2013 by 15 Comments

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Yep, we said it. This Halloween decoration goes way overboard… and we love it! Not only does [Shelby Merrick] put on an incredible sound and light show for the neighborhood, but he keeps us happy by posting all the details for the lighting controller he designed. He calls the creation FloodBrain as it’s switching a set of flood lights to achieve the effects seen above. But for the full experience you’ll want to watch the demo videos below as well.

He needed a way to switch twelve RGB flood lights which pull 10 Watts. His controller was designed to communicate with them via RS485, with an AVR Xmega8E5 controlling the system. We like it that he included some images of the manufacturing process, using a stencil for solder paste before placing components for reflow.

The floodlights themselves are also an interesting hack. To get what he wanted at the best price he picked up 10W white LED flood lights for about eight bucks a piece, then swapped out the LED itself for an RGB version (same wattage) using the same heat sink and case.

More often that not we see this type of system controlling Christmas lights. [Shelby] mentions that he did get help from Christmas light controller forum We also think he should have no problem repurposing the controller for that type of application.

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Trinket Contest Update #4

October 31, 2013 by 8 Comments

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Today is the last day to get your Trinket Contest entries into us! After the break you’ll find another dozen that were sent in. If you’re waiting to see your own appear here please be patient as we’ve got a lot to wade through.

The contest asks you slap the Hackaday logo onto something for a chance at winning one of 20 Trinket dev boards donated by Adafruit for this contest.

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Fail Of The Week: 27 Face Jack-o’-Lantern

October 31, 2013 by 22 Comments

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Sheer luck brings a Halloween themed project for this Fail of the Week post. [Stryker] wrote in to the tips line to share a link to what is an extremely awesome hack. He carved four three different faces on the sides of his pumpkin, then sliced the eyes, nose, and mouth into different sections. Couple this with an internal skeleton made of wood and PVC and he’s got himself a nice hack which lets trick-or-treaters spin the sections to select one of up to 27 different faces.

The sections do spin rather well and the finished project looks fantastic. So what is it that failed? We’ll cover that after the break.

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