Out Engineering A Sneaky Cat

January 31, 2011 by James Munns 31 Comments

Cats do what they want, which rarely coincides with what their owner wants them to do. In [Dumitru]’s case, his girlfriend’s cat [Pufu] tended to make it outside into the cold more often than desired. Rather than settle with the normal bell which gets obnoxious even when the cat isn’t misbehaving, he decided to put together a custom Cat Finding collar. He used a PIC microcontroller as the brains, and temperature and light sensors to decide whether the cat had snuck into the cold, dark night. Once the cat has been marked as being outside, a buzzer and LED are set to go off at regular intervals until returned into the safety of the indoors.

[Dumitru]’s website along with his YouTube videos are in Romanian, though the schematics and source code provided speak for themselves. He does a wonderful job walking through the entire design process, including time spend in the IDE as well as EAGLE designing the board. YouTube has managed to subtitle the majority of the details, but we imagine this post will be a real treat to any Romanian speaking hobbyists out there. Be sure to catch both videos after the break.

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How To Build A Ping-pong Ball Display

January 31, 2011 by Mike Szczys 41 Comments

If you’ve been lusting after your own glowing display we’re here to help by sharing some simple building techniques that will result in an interesting project like the one you see above. This is a super-accurate clock That uses ping-pong balls as diffusers for LEDs, but with a little know-how you can turn this into a full marquee display. Join me after break where I’ll share the details of the project and give you everything you need to know to build your own.

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Insane Covert IR Illumination

January 31, 2011 by Caleb Kraft 37 Comments

[Onironaut] over at lucidscience sent us a link to his latest project, some IR illumination panels. At first, we were mildly enticed by his usual high standard of photography and description. It was just an array of LEDs though. Still, we kept hitting the “next page” button because he goes into such great detail. Then we saw version two. Instead of simply being an array of IR LEDs mounted outside for his security camera, he has mounted 1536 IR LEDs inside an old flat panel monitor. That’s a fake monitor producing 180 watts of IR light, and we think that’s even at half power! He replaced the screen of the display with one way mirror, so you would have no idea that it isn’t just a normal screen sitting on his desk. Great job as usual [Onironaut].

Rovio Headlight Hack Looks Stock

January 5, 2011 by Mike Szczys 12 Comments

Even the most thorough inspection may not raise the alarm that this Rovio has been hacked to include LED headlights. [Adam Outler’s] super clean work puts the two light sources on either side of the camera for maximum effect. It may not provide as many Lumens as our external headlight hack, but we were never all that excited about the black project box that housed it. [Adam] built the circuit on a scrap of perfboard, using a transistor to connect the LED pair to the battery, with the original LED power wire going to the base in order to switch the transistor.

Controlling Real Objects Using Minecraft

January 3, 2011 by Mike Szczys 14 Comments

Most augmented reality takes images of the real world and superimposes virtual data on top of them. [Michael Winston Dales] went a different direction, using the virtual world of Minecraft to control objects in the physical world. In the video after the break you can see him use switches that he built inside the game to turn the LEDs pictured above on and off. You’ll also notice that in-game sign instructing a player to stand in one spot to Tweet. Since Minecraft is written in Java there are some mods that allow you to hook onto in-game events. [Michael] does just that, triggering his own scripts to send data to an Arduino, or use a Twitter API. Now this something that should be used with the Minecraft ALU. It takes the sandbox method of gaming to a new place, doesn’t it?

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Arduino EMF Sensor

December 31, 2010 by Mike Szczys 24 Comments

As a biomedical equipment technician [Adam Outler] equipment needs to be in top working condition. The emergency room staff were complaining about erroneous noise on the electrocardiogram and it’s his job to fix it. He suspected EMF interference so as a quick first step he decided to throw together an EMF detector using an Arduino. It uses a bank of LEDs as an indicator bar to reflect the EMF picked up by the red antenna. In the video after the break [Adam] checks a room for possible sources of interference, treating the recharging circuit from the emergency lights as the most likely culprit. Since the ECG is many times more sensitive to EMF than the Arduino, this turns out to be a quick and easy way to make sure he’s not barking up the wrong tree.

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Accidental LED Fabrication

December 28, 2010 by Mike Szczys 36 Comments

[Grenadier] had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased. So what’s going on here? According to an informed discussion on the phenomenon there’s actually a pair of diodes in series but with their polarity reversed.