LED Hacks

1863 Articles

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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Stereo Microscope Teardown

April 3, 2017 by 19 Comments

Stereo microscopes are very handy tools, especially for a lot of hackers who now regularly assemble, test and debug SMD circuits using parts as small as grains of sand. We have seen a lot of stereo microscope hacks here at Hackaday, so it helps to take a look inside one to understand how they work. Thanks to [noq2]’s teardown of a Wild Heerbrugg model M8 stereo microscope, we get to do exactly that. His M8 is from the mid-1970s, but it is in mint condition and doesn’t look like it’s over 40 years old. Despite being so old, [noq2] still uses it regularly, so the teardown is not super detailed. But there’s enough for us to get a good idea of how they work.

Stereo microscopes use one of two optical designs — the Common Main Objective (CMO) optical system and the Greenough optical system. [MicroscopeWorld] has a nice blog post explaining these two types and their pros and cons. Not surprisingly, stereo microscopes, just like other optical instruments, are highly modular to allow attaching various extensions, adapters and accessories. The Wild M8 uses the CMO design and its main parts are the binocular head, the main body and the objective lens.

The binocular head consists of the two eyepieces and a pair of prisms that create the binocular split. The alignment of these prisms is critical and they must not be disturbed in their mounting cages. The prism cages have a sliding adjustment to help set the interpupillary distance. The main body contains the zoom and magnification optics and the related mechanics. [noq2] is impressed with the lack of plastics used in the construction of these fine instruments. Finally, there’s the huge objective lens, which [noq2] feels is the Achilles heel of the instrument. Its design is not plan-apochromatic and that causes significant chromatic aberrations, especially when trying to capture photographs. Thankfully, there are other objective lenses which can be used, including some DIY adapter solutions. The Wild Heerbrugg brand was taken over by Leica who still produce a range of stereo microscopes under that badge. If you have one of these microscopes, [noq2] suggests you head over the French forum at lenaturaliste.net where you’ll find extensive information about them.

As a bonus, also check out [noq2]’s ghetto lighting solution for his microscope – a pair of high power LED’s attached to salvaged heatsinks, and mounted on the frame of an old 80 mm cooling fan. The fan frame is perfect since it is the right size to slide over the objective lens. If you’re looking for a more capable lighting solution for your microscope, then check out “AZIZ! Light!”, a microscope ring light with a number of different features.

Daunting Interactive LED Dancefloor Build Is Huge Win

March 24, 2017 by 13 Comments

If you’ve ever thought about having a light-up dance floor at an event, the chances are you will have been shocked at the rental cost. Doing your best impression of a young John Travolta in Saturday Night Fever doesn’t come cheap, it seems. When faced with this problem before the Furnal Equinox 2017 convention, [Av] and friends decided instead to build their own LED-lit floor.

Their design and build is shown in the video we’ve placed below the break, and though each individual light unit is straightforward it is the scale of the project and its epic build that makes it a very impressive achievement. There are 64 panels of 4 light cells, giving a total of 256 cells and 7680 RGB LEDs arranged as 2560 pixels. Each panel has a shift register PCB interfacing LEDs to the Teensy that controls the floor, and there are also microswitches talking to an Arduino Mega which provides the floor with interactivity. It’s hard to imaging this build would be possible without the people numerous who pitched in at the Toronto Hacklab for the assembly process.

The resulting 17 foot square dancefloor is a work of art, with custom programmed graphics responding to dancers moves, and even a few games along the lines of Dance Dance Revolution built in. After watching the video below, how many of you will secretly want one?

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Light-Painting Robot Turns Any Floor Into Art

March 20, 2017 by 11 Comments

Is [SpongeBob SquarePants] art? Opinions will differ, but there’s little doubt about how cool it is to render a pixel-mapped time-lapse portrait of Bikini Bottom’s most famous native son with a roving light painting robot.

Inspired by the recent trend of long exposure pictures of light-adorned Roombas in darkened rooms, [Hacker House] decided to go one step beyond and make a lighted robot with less random navigational tendencies. A 3D-printed frame and wheels carries a pair of steppers and a Raspberry Pi. An 8×8 Neopixel matrix on top provides the light. The software is capable of rendering both simple vector images and rastering across a large surface to produce full-color images. You’ll notice the careful coordination between movement and light in the video below, as well as the impressive turn-on-a-dime performance of the rover, both of which make the images produced so precise.

We’ve covered a lot of light-painting videos before, including jiggering a 3D-printer and using a hanging plotter to paint. But we haven’t seen a light-painter with an essentially unlimited canvas before. We’d also love to see what two or more of these little fellows could accomplish working together.

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Build Your Own Animated Turn Signals

March 13, 2017 by 79 Comments

Automotive lighting used to be strictly controlled, particularly in the United States — anyone remember sealed beam headlamps? These days, pretty much anything goes. You can even have an animated turn signal, because a simple flash isn’t fancy enough these days. You can get a scanning-LED turn signal on your new model Audi, among others. [Shravan] wanted this on their Mazda and set about building an animated turn signal and daytime running lights setup for their car.

It’s not a complicated build by any means; an off-the-shelf WS2812B strip provides the blinkums, an Arduino Nano the smarts. Using a modified library to drive the LEDs allowed [Shravan] to get things running with a minimum of fuss. We’d love to see a little more of the gritty reality of this build — how the Nano is getting directional signals from the car, and how it’s all wired up and bolted on. When you’re installing custom hardware onto a vehicle, the devil really is in the details. It’s supremely difficult to create something that looks tidy and functions well.

It’s amazing to think about how far we’ve come. When high-brightness LEDs first came on to the market in the 1990s, you would have been on the hook for wiring your own loom to connect the 20+ LEDs, building your own driver circuitry, and likely etching a custom PCB — all the while you programmed a PIC in assembly as it dangled off a parallel-port programmer. But then again, our cave-dwelling ancestors didn’t even have matches. Time marches on. Use today’s technology to build the very best things you can.

We love seeing car mods, particularly those that are well executed. Check out [Dave]’s interior lighting mods to the Nissan Juke — a car this writer has weighty opinions about. Video after the break.

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