Helicopter light painting continues to snuff out physics lesson on your brain

May 14, 2012 By Leave a Comment

Cool picture, huh? Wait until you see the video footage of this LED-adorned RC helicopter flying on a dark night. But this isn’t an art project. Analyzing the long-exposure photography turns out to be a great way of clearing up some of the physics of flight which otherwise are not at all intuitive. The helicopter used here has different colored lights on the nose and tail, as well as lights on the rotors.

Depending on how the aircraft is moving, different 3D spirography is captured by the camera. When you zoom in on part of the flight path it becomes clear that there are wider arcs on one side of the fuselage than there are on the other. This has to do with the forward progress of the aircraft and the rotation of the blades. The phenomenon is well known by helicopter enthusiasts, and accounted for in the design. But what we didn’t realize is that it actually translates to a theoretical speed limit for the aircraft. Our childhood love of Airwolf — the TV helicopter that could outrun jets — has been deflated.

You should remember the helicopter physics videos featured here last month. This is the latest offering and we’re still wanting more!

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Filed Under: featured, led hacks, toy hacks Tagged With: , ,

Recycle lithium cells by building custom flashlights

May 14, 2012 By Leave a Comment

This isn’t a brightest flashlight in the world type of hack (but it does manage to push about 1000 lumens). [Stephen Webb] is finding a use for leftover parts by building his own simple LED flashlights. As you can see, he uses PVC parts available at any hardware or home store. These are a good choice; they’re cheap, light weight, resilient, designed to be water tight, they easily thread together and have connectors that reduce the diameter of the fittings.

The electronics use standard size cylindrical Lithium cells. These are found in many types of Laptop and Power Tool batteries. Often when one of those battery packs bites the dust it’s an issue of one or more bad cells. [Stephen] desolders the cells, and reuses the good ones in this project.

We didn’t see any mention of a recharging technique. Does anyone have any advice on how to top these cells off if they’re not in their original power pack form?

Filed Under: green hacks, led hacks Tagged With: , , ,

extremely detailed light painting bar

May 10, 2012 By Leave a Comment

[Matt Pandina] has been documenting his build of a very nice light painting bar on his G+ page. His light painting bar has 64 RGB LEDs being driven by an ATmega328P and four TLC5940 chips. He wrote his own libraries to talk to the TLC5940 as well as his own libraries to pull images off of a MicroSD card. He also wrote a cross-platform program that automatically converts a directory  of pngs to something the TLC5940s expect. He says the secret to getting his24-bit color correction looking right is gamma correction. It seems that when the LEDs were run too bright, he couldn’t get the colors quite right.  In case you’re curious, those images are 15 inches tall!

You can follow along through his posts as he starts with just a few LEDs and slowly updates and grows it to the impressive state it is at currently.

Filed Under: hardware, led hacks Tagged With: ,

Builing a bigger bar graph

May 10, 2012 By Leave a Comment

Take a gander at the Giant LED bar graph which [Chunky Hampton] recently completed (from this image we don’t think the nick name suits him). It’s simple both mechanically and electrically, but we love the look and think it would be a nice addition to your home, hackerspace, or as a children’s museum exhibit (we’re looking at you [Mr. Porter]).

The enclosure is a hunk of PVC electrical conduit. It’s got to be one of the largest sizes, but still should be found at most home stores. The base mounts easily and the cover snaps into place. [Chunky] used a hole saw to create the openings for the LED modules. They’re circular boards with multiple single-color LEDs on them. A common power bus feeds the high side of each bit, while a couple of transistor ICs controlled by 595 shift registers address them on the low side. From there just use any controller you wish, but in this case it’s an Arduino.

[Chunky] uses the meter to display power output from his stationary bicycle generator. But he also put together a little Larson Scanner demo which you can see after the break.

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Filed Under: led hacks Tagged With: , , , ,

Reverse engineering an RGB LED remote

May 10, 2012 By Leave a Comment

In the quest to add some mood lighting in his basement, [Mohonri] found an infrared wireless remote that is able to control several RGB LED strips. The only problem with this remote is the inability to control it via a wall-mount panel or even a computer. Obviously this would not stand for such a swank basement, so [Mohonri] did the reasonable thing and reverse engineered one of these remotes.

The build started with ripping the remote apart and figuring out how it ticks. [Mohonri] found the small IR LED transmitter and hooked up an oscilloscope to capture some data. After a bunch of trial and error and a big help from relevant documentation he had the entire button matrix – and thus the functions available to the LED strip – available to output via wall panel or computer.

[Mohonri] hasn’t completed his build yet; this was just the reverse engineering and documentation stage. Now, though, it shouldn’t be hard to control the RGB LED strips through an Arduino, a computer, or even an Android/iOS device with a small IR LED plugged into the headphone jack.

Filed Under: led hacks Tagged With: ,

Robotic light painting in 3D

May 9, 2012 By Leave a Comment

For the last few months, [Ben] has been building a 3D light painting robot. Instead of a couple Arduino-controlled LEDs that a person moves around the Lightplot, as [Ben] calls it, uses a robotic arm to move a LED in 3D space.

The build started with [Ben] testing his idea by putting a laser pointer on an altitude and azimuth mount made out of LEGO. Eventually [Ben] decided to build a 3D plotter rig for a more impressive show. The 3D plotter sits in on a tripod with three axes of motion – up and down, clockwise and counterclockwise, and ‘in’ and ‘out’. A small RGB LED at the end of the robotic arm is controlled along with the servos and motors, making it possible to plot vector lines in 3D space.

There are a whole bunch of demo videos after the break. They look fantastic, but we’d really like to see the Lightplot be used outside on a dark, starry night.

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Filed Under: led hacks Tagged With: , ,
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