LED Hacks

1862 Articles

Flashing LEDs Protect Livestock From Lion Attacks

October 6, 2012 by 50 Comments

When we think of defense against lion attacks, the first thought is usually guns. Lots and lots of guns.  [Richard Turere], a 13 year old Kenyan tinkerer with neither books nor any technical education, has come up with something entirely different – He’s keeping the lions at bay with a solar powered system of flashing LEDs. Yup. Flashing LEDs.

Since he and his family live next to Nairobi National Park, lion attacks are an ever present danger. The only defense systems available were far too expensive for his family to afford, so he decided to build his own. He utilized the basic resources he had readily available: LED bulbs removed from broken flashlights, some switches, an old car battery, wire, and a solar panel that also operates his family’s TV.

The results speak for themselves. His family has had no lion attacks in over two years, and at least five of his neighbors believe in the system enough to have had him install it on their fences too. With the cost for this set up at less than ten dollars, and all the parts being readily available, this rather basic electrical system is an amazing breakthrough for the Kenyan pastoralists.

We look forward to seeing more of [Richard’s] inventions. Way to go!

LED Cyber Eyes; More Nerdy Than Just Taping Your Glasses

October 5, 2012 by 11 Comments

Regular glasses are okay, but these light up and respond to your movement. [Dr. Iguana] is at it again, designing a very interestingly shaped PCB to augment your visual augmentation devices.

The circuit board has two thin curving wings which conform to the shape of a pair of glasses. In the middle there’s a larger area that holds most of the components but it’s still smaller than a common coin cell battery that powers the device. Over each eye there are a half dozen red LEDs which are driven by a PIC 12F1840. It can flash a bunch of patterns the but the interactivity is the real gem of the project. The doctor included an MMA8450 3-axis accelerometer. As you can see in the clip after the break, shaking your head this way and that will be reflected in the pattern of lights.

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Another Automatic Air Freshener Use

October 5, 2012 by 3 Comments

air-freshener-leds-red-on

We’ve seen air fresheners used for many hacks here at hackaday. This one is a bit different as it uses the PIR sensor assembly to turn on LEDs in sequence, rather than reversing a motor. Generally, the motor would be reversed by the fact that this assembly is reversing the voltage on a motor (see [H Bridge] on Wikipedia), but instead it turns on one set of LEDs and then the other.

This works because a diode (the “D” in LED) only allows current to flow one way. The LEDs are reversed with respect to the voltage source, making them come on in sequence. An Arduino or other microprocessor could of course be used to accomplish the same thing (see this [HAD] post about harvesting the PIR sensor only). However, if you had $10 or less to start your hardware hacking career, this is yet another way an air freshener can be hacked up to do your bidding.

Be sure to see the video of this simple hack after the break, used to “LED-ify” a Star Wars AT-ST painting. If you’re interested in using the gears and motor of an air fresher as well, why not check out this post on remotely triggering a camera with the internals from a time-based model? Continue reading “Another Automatic Air Freshener Use” →

Laser-etched LED Zeotrope Looks Like A Circular Monochrome Screen

October 3, 2012 by 12 Comments

The still image of this animated display really doesn’t do it justice. But you can get an idea of how this really does look like an old monochrome display. It’s actually a zeotrope made from LEDs and etched acrylic. The LEDs blink at a rate that synchronizes with the spinning acrylic to produce an animated image.

You probably already know that a zeotrope uses moving physical models to trick the eye into seeing an animation. In this case the models are etched into a piece of acrylic so that their outline glows when the material is edge-lit. Twelve pie piece shaped panes were designed in Inkscape to look like a scene from the Linux game World War IV. A stepper motor spins the ring which allows for the perfect synchronization seen in the clip after the break.

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Nixie Suduku And On-die LEDs

October 2, 2012 by 18 Comments

The best booths at Maker Faire draw you in with something unbelievably cool or ridiculously absurd, and bring out a state-of-the-art technology just as your curiosity for the main feature starts to wane. [John Sarik]’s booth for a class he’s TAing at Columbia – Modern Display Science and Technology – is one of these booths.

The main feature of the booth is a suduku board filled with 81 Nixie tubes. As shown in the video below, you control the cursor (the decimal point of the Nixies) with a pair of pots. After moving the cursor to the desired location, there’s a keypad to change the number at any one of the 81 locations on a suduku puzzle.

[John]’s presentation then continued to what he’s working on up at Columbia: he’s working on a project to put arrays of LEDs onto silicon, just like any other integrated circuit. He demoed a small LED display built in to a DIP-40 package with a glass (or maybe quartz) window. Yes, it’s a really tiny LED matrix display with a pixel pitch probably much smaller than a traditional LCD display.

Video of the suduku machine after the break, as well as a gallery of the LED matrix on a chip. The matrix was very hard to photograph, so if [John] would be so kind as to send a few more pics in, we’ll be happy to put them up. There’s also a proper video from [John]’s YouTube showing off the Nixie Suduku puzzle solving itself with a recursive algorithm.

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Build A POV Death Star, You Will

October 1, 2012 by 26 Comments

Building a Persistence of Vision globe is pretty awesome, but overlaying a Death Star pattern on the display takes it to the next level of geekery. Like us, [Jason] has wanted to build one of these for a long time. His success pushes us one step closer to taking the plunge and we hope it will inspire you to give it a shot too.

As he mentions in the beginning of his write up, the mechanical bits of these displays are really where the problems lie. Specifically, you need to find a way to transfer power to the spinning display. In this case use went with some DC motor brushes. These are replacement parts through which he drilled a hole to accept the metal axles on top and bottom. We hadn’t seen this technique before, but since motor brush replacements are easy to find and only cost a few bucks we’d say it’s a great idea.

The 24 blue LEDs that make up the display are all on one side of the PCB. They’re driven by an ATmega328 running the Arduino bootloader. [Jason] uses an FTDI adapter to program the chip. Don’t miss the video embedded after the break.

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StarGate Eggbeater

September 24, 2012 by 5 Comments

[Jason] used a strip of 142 Adafruit LPD8806 Addressable RGB LEDs to create the StarGate Eggbeater persistence of vision display. The LED strips are controlled by an Arduino Mega, which is used to control the strip and provides 21 bit color control for each LED. The strip is housed into a ring-shaped tube which is mounted onto a rod and bearing to allow it to spin. A 1/4 HP motor is used to spin the ring at 250 RPM creating the POV effect.

One issue when controlling a spinning object is making electrical connections to a spinning object. The LPD8806 requires four connections: power, ground, clock, and data. To make the connections, [Jason] used a MOOG Slip Ring. This allows for the four connections to be made while the ring spins at 250 RPM.

Of course POV demos need videos, so check one out the “boss program” video after the break.

Via Adafruit

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