1575 Bottles of Beer on the (LED) Wall

Say hello to my little friend, lovingly named Flaschen Taschen by the members of Noisebridge in San Francisco. It is a testament to their determination to drink Corona beer get more members involved in building big displays each year for the Bay Area Maker Faire. I pulled aside a couple of the builders for an interview despite their very busy booth. When you have a huge full-color display standing nine feet tall and ten feet wide it’s no surprise the booth was packed with people.

Check out the video and then join me after the break for more specifics on how they pulled this off.

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Exquisite LED Handbag in the Wild

There is a lot of spectacle on display at Maker Faire. But to be honest, what I love seeing the most are well-executed builds pulled off by passionate hackers. Such is the case with [Debra Ansell]. She wasn’t exhibiting, just taking in all the sights like I was. But her bag was much better than my drab grey camera-equipment filled backpack; she build a handbag with an LED matrix and did it so well you will scratch your head trying to figure out if she bought it that way or not.

Gerrit and I walked right up and asked if she’d show it to us. We weren’t the only ones either. [Debra’s] bag started drawing a crowd as she pulled out her cellphone and sent “Hackaday” to the 10×15 matrix over Bluetooth. Check out our video interview below.

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Real-time Driving of RGB LED Cube using Unity3D

RGB LED cubes are great, but building the cube is only half the battle – they also need to be driven. The larger the cube, the bigger the canvas you have to exercise your performance art, and the more intense the data visualization headache. This project solves the problem by using Unity to drive an RGB LED cube in real-time.

Landscape animation RGB Cube - smallWe’re not just talking about driving the LEDs themselves at a low level, but how you what you want to display in each of those 512 pixels.

In the video, you can see [TylerTimoJ]’s demo of an 8x8x8 cube being driven in real-time using the Unity engine. A variety of methods are demonstrated from turning individual LEDs on and off, coloring swaths of the cube as though with a paintbrush, and even having the cube display source image data in real-time (as shown on the left.)

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Stealthy Mortar Board Unleashes Bling at Graduation Ceremony

Decorating graduation caps is often frowned upon by the administration but [Dan Barkus] is challenging his school authorities to keep from smiling when they see what he has in store. His build will dazzle the audience by mounting 1024 RGB LEDs in a 32×32 matrix on top of his cap, but hidden under the cap’s black cloth. When the LEDs are off he’s indistinguishable, and when he fires up the LEDs, shine through and put on a heck of a show. He can type messages on his phone to be displayed on the cap. He can even display images and animated GIFs.

LED array control components
LED array control components

The LED display is an Adafruit 32×32 RGB LED matrix panel.  To control the display, [Dan] uses a Teensy, a 32 bit ARM Cortex-M4 microcontroller board. Wireless communication is done via a JBtek HC-06 Bluetooth board.

The LED display can draw up to 4 amps at full white brightness so he picked up a USB battery with two output ports, one capable of 2.1 amps and the other 2.4 amps. He then hacked together a cable that has two USB connectors on one end, connected in parallel, and a DC jack on the other end. Altogether the battery bank is capable of up to 4.5 amps output combined out those two ports, meeting the LED display’s needs. The DC jack is plugged into the Teensy and all power goes through there.

One problem [Dan] had was that the Bluetooth module was booting up before the Teensy. It didn’t see the Teensy in time, causing the Bluetooth not to work. The solution he found is shown in the 2nd video embedded below. The fix powers the Bluetooth module separately, using a current limiting resistor and a capacitor to build up the voltage, delaying just long enough for the Teensy to win.

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Amazing Analysis of a 350,000 LED Airport Art Project

Before you zip to the comments to scream “not a hack,” watch a few minutes of this teardown video. This 48 minute detailed walkthrough of a one-off art piece shows every aspect of the project: every requirement, design decision, implementation challenge, and mistake. Some notable details:

  • PCBs that are 1 meter wide (all one piece!)
  • 350,000 white LEDs
  • Carbon fiber enclosures
  • 1-wire serial bus (like the WS2812 only not quite) with 12 bit resolution (TLC5973)
  • Customized cable test jigs, PCB test jigs, and test modes
  • An exploration on ESD issues in production

It’s not often that one sees teardowns of professional projects like this, and there’s quite a bit to learn from in here, besides it being a beautiful piece of art. See more about the Caviar House “Emergence” project at the Heathrow Airport, along with stunning pictures and video of the display in action.

If you’re thinking about how you’d control 350,000 individual LEDs with 12 bit grayscale and have it look smooth, check out the processor requirements behind the megascroller, which only handles 98,000 LEDs. More recently, we asked how many LEDs are too many, and the answer was quite a bit lower than 350k.

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Color-Changing LED Makes Techno Music

As much as we like addressable LEDs for their obedience, why do we always have to control everything? At least participants of the MusicMaker Hacklab, which was part of the Artefact Festival in February this year, have learned, that sometimes we should just sit down with our electronics and listen.

With the end of the Artefact Festival approaching, they still had this leftover color-changing LED from an otherwise scavenged toy reverb microphone. When powered by a 9 V battery, the LED would start a tiny light show, flashing, fading and mixing the very best out of its three primary colors. Acoustically, however, it spent most of its time in silent dignity.

singing_led_led_anatomy

As you may know, this kind of LED contains a tiny integrated circuit. This IC pulse-width-modulates the current through the light-emitting junctions in preprogrammed patterns, thus creating the colorful light effects.

To give the LED a voice, the participants added a 1 kΩ series resistor to the LED’s “anode”, which effectively translates variations in the current passing through the LED into measurable variations of voltage. This signal could then be fed into a small speaker or a mixing console. The LED expressed its gratitude for the life-changing modification by chanting its very own disco song.

singing_led_hook_up_schematic

This particular IC seems to operate at a switching frequency of about 1.1 kHz and the resulting square wave signal noticeably dominates the mix. However, not everything we hear there may be explained solely by the PWM. There are those rhythmic “thump” noises, shifts in pitch and amplitude of the sound and more to analyze and learn from. Not wanting to spoil your fun of making sense of the beeps and cracks (feel free to spoil as much as you want in the comments!), we just say enjoy the video and thanks to the people of the STUK Belgium for sharing their findings.

A 3D-Printed Engagement Ring

[Hans Peter] had reached the moment of popping the question. Going down on one knee and proposing to his girlfriend, the full romantic works.

He’s a brave man, [Hans]. For instead of heading for the jeweller’s and laying down his savings on something with a diamond the size of a quail’s egg he decided that his ring should contain something very much of him. So he decided to 3D print a ring and embed a slowly pulsing LED in it. He does mention that this ring is a temporary solution, so perhaps his soon-to-be-Mrs will receive something sparkly and expensive in due course.

To fit his LED and flasher in such a small space he used a PIC10F320 microcontroller that comes in a SOT-23-6 package. This was chosen because it has a handy PWM output to pulse the LED rather than flash it. This he assembled dead-bug style with an 0603 LED, and a couple of hearing aid batteries to power the unit. He has some concerns about how long the hearing aid batteries will power the device, so as he wrote he had better hurry and get on his knees. (He informs us in his tip email that she said yes.)

Surprisingly we’ve covered quite a few engagement ring builds over the years. Closest to this one is an LED ring powered by an induction coil, but we’ve also featured machined titanium rings and some rather nice cast rings.