LED Hacks

1897 Articles

From 300W To 10W — A LED Lighting Solution

June 16, 2014 by 32 Comments

LED halogen light

Halogen lights are great — they produce lots of bright warm light, but they suck a lot of juice to run. [Sven] had found a nice floor lamp years ago that was in pretty rough shape — his wife redecorated it, and he fixed it up, but between the 300W power consumption and the lack of a dimmer circuit (this thing was bright!), he knew he had to upgrade.

Like we recommend for all projects, [Sven] started by setting some goals for the conversion. He wanted to keep the warm light color tone, produce over 700lm, allow for dimming via remote, and work with presence detection.

He sourced a 10W power LED which requires 12V @950mA to run, which almost stumped him as it turns out there aren’t many LED drivers of that specification even available! Luckily, he managed to find one from China that wasn’t too large and would fit in the lamp cover with the other components. He found a large heat sink for the LED, and for safety, has even wired it up with a temperature sensor to his Arduino in order to shut it down if it gets too hot. The Arduino also provides the dimming circuit and remote control capabilities.

[Sven] admits that the end result isn’t that pretty, but lucky for him, it stands about 6′ tall so no one can see the jumble of wires and components inside! This is also only the first iteration, as he plans on upgrading it further — as it turns out, 700lm isn’t quite enough.

Industrial Light Painting Steps It Up A Few

June 5, 2014 by 4 Comments

industrial light painting

What would you do if you had access to an industrial ABB IRB 6640 robot? We’d probably make a giant 3D printer, but if you’re [Jeff Crossman] and [Kevyn McPhail], you’d make one of the most advanced light painting setups we’ve ever seen.

The setup itself is really quite simple — a single RGB LED is connected to a Teensy microcontroller on a tool-head for the robot — controlling the robot is the hard (fun?) part. To create the images, [Jeff] had several students come in to have their photographs taken using a Microsoft Kinect. This allowed him to create an RGB point cloud for the robot to recreate.

Using Rhino he created the tool paths required for the robot to build up a floating 3D image of the students for the camera taking the long exposure. Each demonstration made use of ~5000 points, which takes the robot arm about 25 minutes to place.

It’s a fascinating video, and yes it does seem like a bit of overkill, but hey — why not?

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The Megascroller, For Video Games In The Round

June 5, 2014 by 23 Comments

megascroller

The folks at NYC Resistor have a thing for circular displays, it seems. Their earlier Hexascroller was a ceiling mounted display with six 30×7 displays – good enough to display the time and a few textual message in six directions. The Octoscroller bumped up the display capability with eight 16×32 RGB LED panels. Now the Megascroller, a 32-sided 512×64 display is hanging in the hackerspace, complete with 360° Mario and Pong.

The Megascroller is one of [Trammell Hudson]’s projects, constructed out of sixty-four 32×16 RGB LED matrices. That’s an impressive amount of controllable LEDs, that required a lot of processing power: namely, the BeagleBone-powered LEDscape board used in their earlier Octoscroller

As far as applications go, they naturally have Pong, but a more interesting application is the side-scrolling Mario that requires you to move around the display as you play. You can check out a video of that below.

If you’d like to see the Megascroller in person, as well as a whole bunch of other crazy blinking interactive projects, NYC Resistor is holding a an interactive show this weekend, beer provided.

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Koch Lamp Is 3D Printed With A Twist

June 1, 2014 by 11 Comments

Koch Lamp

[repkid] didn’t set out to build a lamp, but that’s what he ended up with, and what a lamp he built. If the above-pictured shapes look familiar, it’s because you can’t visit Thingiverse without tripping over one of several designs, all based on a fractal better known as the Koch snowflake. Typically, however, these models are intended as vases, but [repkid] saw an opportunity to bring a couple of them together as a housing for his lighting fixture.

Tinkering with an old IKEA dioder wasn’t enough of a challenge, so [repkid] fired up his 3D printer and churned out three smaller Koch vases to serve as “bulbs” for the lamp. Inside, he affixed each LED strip to a laser-cut acrylic housing with clear tape. The three bulbs attach around a wooden base, which also holds a larger, central Koch print at its center. The base also contains a PICAXE 14M2 controller to run the dioder while collecting input from an attached wireless receiver. The final component is a custom control box—comprised of both 3D-printed and laser-cut parts—to provide a 3-dial remote. A simple spin communicates the red, green, and blue values through another PICAXE controller to the transmitter. Swing by his site for a detailed build log and an assortment of progress pictures.

 

Custom Electronics And LED Panels Brighten Up A Nightclub

May 31, 2014 by 8 Comments

ledPanels

When [Robert] is presented with a challenge, he doesn’t back down. His friend dreamed of reusing some old LED panels by mounting them to the ceiling of the friend’s night club. Each panel consists of a grid of five by five red, green, and blue LEDs for a total of 75 LEDs per panel. It sounded like a relatively simple task but there were a few caveats. First, the controller box that came with the panels could only handle 16 panels and the friend wanted to control 24 of them. Second, the only input device for the controller was an infrared remote. The friend wanted an easy way for DJ’s to control the color of the panels and the infrared remote was not going to cut it. Oh yea, he also gave [Robert] just three weeks to make this happen.

[Robert] started out by building a circuit that could be duplicated to control each panel. The brain of this circuit is an ATtiny2313. For communication between panels, [Robert] chose to go with the DMX protocol. This was a good choice considering DMX is commonly used to control stage lighting effects. The SN75176 IC was chosen to handle this communication. In his haste to get this PCB manufactured [Robert] failed to realize that the LED panels were designed common cathode, as opposed to his 25 shiny new PCB’s which were designed to work with a common anode design. To remedy this, he switched out all of the n-channel MOSFET with p-channel MOSFET. He also spent a couple of hours manually cutting through traces and rewiring the board. After all of this, he discovered yet another problem. The LED’s were being powered from the same 5V source as the microcontroller. This lead to power supply issues resulting in the ATtiny constantly resetting. The solution was to add some capacitors.

Click past the break for more on [Robert’s] LED panels.

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Driving 1000 NeoPixels With 1k Of Arduino RAM

May 19, 2014 by 36 Comments

timing

NeoPixels, or WS2812 RGB LEDs, are the display device du jour for impressive and blinding lighting projects. Commonly known for very tight timing requirements, [Josh] discovered this is, in fact, usually unnecessary. The timing requirements for NeoPixels aren’t as bad as they seem, once you get to know them.

The official WS2812 timing specs give values that are fairly constraining for anyone writing a library to drive these RGB LED pixels, but simplifying the timing diagram by assuming a 50% duty cycle on the data lines and ignoring the longer maximum times results in a surprising conclusion: the only tight timing parameter for NeoPixel signaling is the maximum width of the 0-bit pulse.

Realizing this, [Josh] wrote a simple demo program to drive over 1000 NeoPixels – an 11 meter long strip – using 1K of RAM on an Arduino. The trick comes by simply delaying the bitbanging a set number of cycles. No obtuse assembly required.

There is only one problem with [Josh]’s method of driving a nearly unlimited amount of NeoPixels – building a display where every NeoPixel is an element in a larger image, such as in a video display, is impossible on systems with limited amounts of RAM. The code writes values to the NeoPixel strip algorithmically, so if you can’t build your animation with for loops, you’re out of luck. Still, Driving this many NeoPixels is a migraine trigger, and we have to give [Josh] credit for doing this with 1K of RAM.

Check out the video of [Josh]’s extreme NeoPixel strip below.

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A Raspi Ambilight With HDMI Input

May 18, 2014 by 19 Comments

With the Raspberry Pi now most famously known as a $30 media PC, it only makes sense that the best uses for the GPIO pins on the Pi are used for an Ambilight. [Great Scott Labs] put up a great video on using the Pi as a uniquely configurable Ambilight with Hyperion and just about any video input imaginable.

This isn’t the first Ambilight clone [Great Scott] has put together, but for the first version the Ambilight functioned only under Raspbian and not any random HDMI input. The new version solves this by using an HDMI splitter box, feeding into an HDMI to composite converter, and finally into a USB composite capture dongle attached to the Raspi.

With the software in the instructions, the Raspi effectively mirrors the video coming from the video capture dongle. The Pi is running Hyperion to control a strip of WS2801 RGB LEDs, making the back of any TV glowey and blinkey.

Since [Great Scott] is using a component video signal as an input, the adapters necessary to have any device work with this Ambilight are readily available. We’d honestly like to see this build working with the old Commodore disk access screen border going nuts, so be sure to send that in if you ever get that working.

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