LED Hacks

1825 Articles

A Smart Table For Gamers

May 5, 2017 by 9 Comments

When makers take to designing furniture for their own home, the results are spectacular. For their senior design project, [Phillip Murphy] and his teammates set about building a smart table from the ground up. Oh, and you can also use it to play games, demonstrated in the video below.

The table uses 512 WS2812 pixels in a 32 x 16 array which has enough resolution to play a selection of integrated games — Go, 2-player Tetris, and Tron light cycle combat — as well as some other features like a dancing bird party mode — because what’s the point of having a smart table if it can’t also double as rave lighting?

A C2000-family microcontroller on a custom board is the brains, and is controlled by an Android app via Bluetooth RN-42 modules. The table frame was designed in Sketchup, laser-cut, and painstakingly stained. [Murphy] and company used aluminum ducting tape in each of the ‘pixels’, and the table’s frame actually forms the pixel grid. Check out the overview and some of the games in action after the break.

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Hackaday Prize Entry: Brightenmacher

April 25, 2017 by 19 Comments

We have all at some point have made a flashlight. It used to be a staple of childhood electronics, the screw-in bulb in a holder, and a cycle lamp battery. If you were a particularly accomplished youthful hacker you might even have fitted a proper switch, otherwise, you probably made do with a bent paperclip and a drawing pin.

So you might think that flashlights offer no challenges, after all, how many ways can you connect a bulb or an LED to a battery? [Peter Fröhlich] though has a project that should put those thoughts out of your mind. It uses a power LED driven by a TI TPS61165 boost driver, with an ATTiny44 microcontroller providing control, battery sensing, and button interface. The result is a dimmable flashlight in a 3D printed case housing both control circuitry and a single 18650 cell which he sourced from a dead laptop. Suddenly that bent paperclip doesn’t cut it anymore.

The result is a flashlight that is the equal of any commercial offering, and quite possibly better than most of them. You can build one yourself, given that he’s published the physical files necessary, but probably because this is a work in progress there are as yet no software files.

We’ve featured a lot of flashlights over the years, but it’s fair to say they usually tend towards the more powerful. Back in 2015 we published a round-up of flashlight projects if it’s a subject that captures your interest.

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Ask Hackaday: What About The Diffusers?

April 25, 2017 by 82 Comments

Blinky LED projects: we just can’t get enough of them. But anyone who’s stared a WS2812 straight in the face knows that the secret sauce that takes a good LED project and makes it great is the diffuser. Without a diffuser, colors don’t blend and LEDs are just tiny, blinding points of light. The ideal diffuser scrambles the photons around and spreads them out between LED and your eye, so that you can’t tell exactly where they originated.

We’re going to try to pay the diffuser its due, and hopefully you’ll get some inspiration for your next project from scrolling through what we found. But this is an “Ask Hacakday”, so here’s the question up front: what awesome LED diffusion tricks are we missing, what’s your favorite, and why?

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Hackaday Prize Entry: Portable LED Flash For Photography

April 21, 2017 by 24 Comments

Photography is all about light. It’s literally right there in the name – stemming from the Greek word, photos. This is why photographers obsess over the time of day of a shoot, why Instagrammers coalesce around landmarks at sunset, and why a flash helps you take photos in darkness. Historically, flashes have worked in all manner of ways – using burning magnesium or xenon lamps for example. For this Hackaday Prize entry, [Yann Guidon] is developing a portable flash using LEDs instead.

By this point in time, you might be familiar with LEDs as flash units from your cellphone. However, [Yann] is taking this up a notch. The build is based around 100W LED modules, which obviously can pump out a lot of light. The interesting part of the build is its dual nature. The LEDs are intended to operate in one of two ways. The first is in a continuous lighting mode, running the modules well below their rated power to reduce the stress on the LEDs and power supply, and to enable the flash to run on the order of an hour. In this mode, temperature feedback will be used to control the LEDs to manage power use. The other is a pulsed mode, where the LED will be overvolted for a period of milliseconds to create a much more powerful flash.

It’s this dual nature which gives the LED-based flash a potential advantage over less versatile xenon-based units, which are limited to pulsed operation only. We can see the continuous lighting mode being particularly useful for videographers needing a compact, cheap lighting solution that can also work as a pulsed unit as well.We’re excited to see how [Yann] tackles the packaging, thermal and control issues as this project develops!

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Pi Time – A Fabric RGB Arduino Clock

April 16, 2017 by 4 Comments

Pi Time is a psychedelic clock made out of fabric and Neopixels, controlled by an Arduino UNO. The clock started out as a quilted Pi symbol. [Chris and Jessica] wanted to make something more around the Pi and added some RGB lights. At the same time, they wanted to make something useful, that’s when they decided to make a clock using Neopixels.

Neopixels, or WS2812Bs, are addressable RGB LEDs , which can be controlled individually by a microcontroller, in this case, an Arduino. The fabric was quilted with a spiral of numbers (3.1415926535…) and the actual reading of the time is not how you are used to. To read the clock you have to recall the visible color spectrum or the rainbow colors, from red to violet. The rainbow starts at the beginning of the symbol Pi in the center, so the hours will be either red, yellow, or orange, depending on how many digits are needed to tell the time. For example, when it is 5:09, the 5 is red, and the 9 is yellow. When it’s 5:10, the 5 is orange, the first minute (1) is teal, and the second (0) is violet. The pi symbol flashes every other second.

There are simpler and more complicated ways to perform the simple task of figuring out what time it is…

We are not sure if the digits are lighted up according to their first appearance in the Pi sequence or are just random as the video only shows the trippy LEDs, but the effect is pretty nice:

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A Huge Infra-Red Touch Board

April 11, 2017 by 29 Comments

We’re all used to touch pads on our laptops, and to touch screens. It’s an expectation now that a new device with a screen will be touch-enabled.

For very large surfaces though, touch is still something of an expensive luxury. If you’re a hardware hacker, unless you are lucky enough to score an exceptional cast-off, the occasional glimpse of a Microsoft PixelSense or an interactive whiteboard in a well-equipped educational establishment will be the best you’re likely to get.

[Adellar Irankunda] may have the answer for your large touch board needs if you aren’t well-heeled, he’s made one using the interesting approach of surrounding the touch area with an array of infra-red LEDs and photo transistors. By studying the illumination of the phototransistors by different LEDs in the array, he can calculate the position of anything such as a pointing finger that enters the space. It’s an old technique that you might have found on some of the earlier touch screen CRT monitors.

His hardware is built on twelve breadboards mounted in a square, upon which sit 144 LED/phototransistor pairs managed through a pile of 4051 CMOS multiplexers by a brace of Arduino Nanos. If you fancy one yourself he’s provided all the code, though the complex array of breadboards to assemble are probably not for the faint-hearted. You can see it in action in a video we’ve posted below the break.

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Hackaday Prize Entry: Micro Matrix Charlieplexed Displays

April 4, 2017 by 9 Comments

If you need a very thin, low power display that doesn’t use a whole bunch of pins on your microcontroller, [bobricius] has just the thing for you. His entry to the Hackaday Prize this year is a Charlieplexed LED display. With this board, you can drive 110 LEDs using only 11 GPIO pins.

Charlieplexing is a bit of a dark art around these parts. That’s not to say the theory is difficult; it’s really just sourcing or sinking current from a GPIO pin and arranging LEDs unparallel to each other. The theory is one thing, implementation is another. To build a Charlieplexed LED matrix, you need to go a bit crazy with the PCB layout, and god help you if you’re doing this point-to-point on a perf board.

Somehow, [bobricius] managed to fit 110 LEDs on a PCB, all while managing to break out those signal wires to a sensible set of pads on one side of the board. Only eleven pins are required to drive all these LEDs, making this project a great foundation for some very cool wearables or other projects that require a bright, low-res display.

Since [bobricius] can put 110 LEDs on a small board, he can obviously take LEDs away from that board. That’s what he did with his cut down version designed to be a clock. Both are great little boards, and the perfect solution for tiny displays for low-pin-count micros.

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