Stop Traffic In This 7-Mode LED Running Jacket

[Miria] was tired of tangling with bicyclists on her nighttime runs. It was obvious to her to illuminate herself, but she thought it would be really cool if the lights responded to her heart rate. The short summary that tipped us off is over at NYC Resistor, and [Miria] gives the gory details on her blog. The LEDs operate in seven different light modes that increase in speed proportionate to her heart rate.

She started the build around an Arduino but found that the compatible heart rate sensors were mostly optical and gave inaccurate readings. Since she was already using a Garmin GPS watch and heart rate monitor band, she decided to hack into the conversation between the two. Garmin uses the ANT protocol for this. While [Miria] found the documentation to be an effective sleeping pill, she also found that SparkFun has an ANT transceiver breakout board. Unfortunately, it’s been discontinued.

[Miria] continued undeterred, using the SparkFun board for prototyping. Her final version uses a Teensy 2.0 and this ANT transceiver in place of the ill-fated SparkFun board. She found an Energizer power pack that plugs directly into the Teensy and can power both Adafruit weatherproof LED strips for about an hour. Look both ways, and check out her demo after the break.

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North Street Labs try to spice up a game of Tic-Tac-Toe


The team at North Street Labs really went all out with this Tic-Tack-Toe stomp box. At its most basic it’s a blinky version of the simple two-player game. But there’s always some added appeal when you make large manifestations of normally small items; the 10x Arduino is a good example of this.

The project is NSL’s qualifying entry for this year’s Red Bull Creation Contest (has it already been a year since the last contest?). A special Arduino shield was produced once again, this time it features hardware necessary to control LED strips… a lot of them. That led to the creation of this box, which houses a ton of strip sections inside to light the grid based on tapping one of the red buttons with your foot. We’d image the game would be seldom used at your hackerspace, but they take it to show off at the local children’s museum and it’s a huge hit with the kids!

Sunrise alarm clock mounted above the bed


This sunrise alarm clock was made in a bit different form factor than we normally see. Instead of a box next to the bed it’s a bar above the headboard which slowly illuminates every morning. This was [Holly's] first electronics project. She spent pretty much all summer working on it and accumulated a skill set that included designing for and operating the laser cutter and assembling and programming the electronics.

She didn’t start from square one. The hardware and programming were greatly simplified by the availability of RGB LED strips and the Monochron clock which drives them. [Holly] altered the code to bring up a blueish hue over a 35-minute time period. Since this will be used to wake her at 5:30am she was also obliged to include some backup sounds just in case. But after the project was finished and mounted she forgot to turn them on and was pleasantly surprised that the lights woke her up on time. The mounting bracket seen above uses t-slot rail with laser cut brackets to hold the half-cylinder shade for the sconce. The final product looks fantastic!


A blinky fedora to ring in the New Year


[Garrett Mace] decided to dress festive for New Year’s Eve. What he came up with is a fedora ringed in LEDs that react to music. The hardware uses 5050 LEDs on strips. Three of them encircle the head-gear providing a total of 114 RGB pixels. Each is a WS2811 module — a part which we’re seeing more and more of lately.

The video clip after the break starts off with a few minutes of demonstration. [Garrett] managed to code all kinds of animations for the hardware including several different styles of color sweeps and fades. You may start to think that the three bands always display the same patterns but keep watching and you’ll see a sparkle pattern that proves each dot can be addressed individually.

About 2:20 seconds into the video [Garrett] explains how he pulled it off and shows off the driver hardware. The strips are glued to a band of webbing that slides over the hat. The wires that drive the lights were fed through the center of some paracord and connect to an Arduino housed in a 3D printed case. Power is provided by a portable USB battery with a ShiftBrite shield and an MSGEQ7 chip complete the parts list.

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Adding task lighting inside a desk


[Mahesh Venkitachalam] wanted to light up the dark recesses of his desk. What good is all that storage if you can’t see a darn thing in there? His solution was to add LED strips which turn on automatically when the door is opened.

The design is quite simple. A 2N2222 NPN transistor is responsible for connecting the ground rail of the LED strips mounted under each shelf. The base of that transistor is held high with a pull-up resistor. But a reed switch always connects the base to ground when the door is shut. Opening the door removes the magnet that keeps that reed switch closed. This allows current to flow from the pull-up to the base, connecting the ground rail to the LED strips and turning them on. You can see the video demo after the break.

One problem that we see with the design is that these are driven by a 9V battery. Over a long period of time that pull-up resistor will drain the cell. You can pick up a magnetic reed switch at the hardware or electronics store that is rated for 500 mA. If you can stay under that with the LED strips, and get one that is open when the magnet is present you will have zero power drain when the lights aren’t being used.

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Driving a WS2811 RGB LED pixel


[Alan] has been working on driving this WS2811 LED module with an AVR microcontroller. It may look like a standard six-pin RGB LED but it actually contains both an LED module and a microcontroller to drive it. This makes it a very intriguing part. It’s not entirely simple to send commands to the module as the timing must be very precise. But once the communication has happened, the LED will remain the same color and intensity until you tell it otherwise. You can buy them attached to flexible strips, which can be cut down to as few as one module per segment. The one thing we haven’t figure out from our short look at the hardware is how each pixel is addressed. We think the color value cascades down the data line as new values are introduced, but we could be wrong. Feel free to discuss that in the comments.

The project focuses on whether or not it’s even possible to drive one of these pixels with a 16MHz AVR chip. They use single-wire communications at 800 kHz and this really puts a lot of demand on the microcontroller. He does manage to pull it off, but it requires careful crafting in assembly to achieve his timing constraints. You can see a quick clip of the LEDs fading between colors after the break.

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Disco Planet, a massive RGBW LED array in a 6′ globe

About half a year ago [John] over at Frank’s Kitchens came to me with an idea for a giant lighting project. He had this 6ft diameter aluminum frame globe rescued from the Philadelphia Theater Company and wanted it to be an interactive display of sorts. After a few discussions we got together and somehow managed to order 800 3 watt LEDs in red, green, blue, and white. We had a system that worked great on paper, and managed to get it built by Valentines day for a big show. It failed miserably and hardly even illuminated the LEDs. I, naturally, took this far too personally and set out for a complete redesign, looking in the direction of digitally addressable LED strips.

In addition to building a crazy turbo charged LED array I also spent a lot (a whole lot) of time coding a nice clean fully functioning RGB LED strip controller using an Arduino Pro Mini (5V 16 MHz), the MSGEQ7 audio frequency multiplexer (PDF) , and an IR remote. I plan on using this for other projects so the code can be easily reconfigured to use many different LED strips and a whole slew of IR remotes.

The schematic of the globe is here. The top half  of that schematic be catered to other projects using a variety of pre-built LED strips. The pastebin with code is here,  fastSPI_LED and IRRemote here and here. Some code jockeying was required to get IRRemote.h and FastSPI_LED to play nicely together, so check the code comments.

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