Looks like a commercial LED display sign… right? Not even close. This is a project of [Jon’s] from over a year ago, and it is a very impressive 128×32 LED display board, driven using a single Raspberry Pi.
It’s made of eight “P10” 32×16 LED panels that he bought off of eBay, housed in a wooden frame he built himself. The display runs off of a single Raspberry Pi and can receive a video signal from anything with an Ethernet port. The individual boards are daisy-chained in a rather odd arrangement to minimize cable length, which [Jon] says helps with clocking the data fast — he’s able to parse 2 bits per pixel to refresh the display at an impressive 400+ frames per second.
To power the display, he’s using a single ATX power supply with the Pi connected to the standby 5V power line. This is to avoid a voltage drop which might cause the Pi to crash — when all LEDs are on the display can draw a healthy 32A of juice. The P10’s use shift registers to serially load the pixel data. At any time, the 4096 pixel display can have 1024 pixels on, which means a fairly fast clock is required to update the display.
[Jon] has shared all the source code on his blog, and has a fairly in-depth explanation of all the systems used. Check it out for yourself, and don’t forget to stick around after the break to see the display in action!
Continue reading “Raspberry Pi Driven 128×32 LED sign”
One of the more impressive projects a home-bound tinkerer can pull off is some sort of display. Not only does the final project result in a lot of blinky, glowey things, but driving hundreds of LEDs is an achievement in itself. [Fabien] decided he wanted to build his own LED display and ended up with something great (French, Google translation).
Instead of going off the deep end and making his own boards for this giant LED display, [Fabien] found a very cheap 16×32 LED display board on DealExtreme. Once these kits were pieced together, [Fabian] mounted them in a wooden frame and started connecting the displays together.
The original plan was to drive these with an Arduino, but with so many pixels he quickly ran out of RAM. Replacing the Arduino with a larger ATMega1284p, [Fabian] found the RAM he needed and started work on some interesting visualizations.
Of course, Conway’s Game of Life made a showing in the final build, but [Fabian] also managed to whip up a spectrograph using FFT. It’s a very nicely put together display that makes us want to buy a few of these displays ourselves.
This year the Disorient Camp at Burning Man built a 7m tall pyramid with over half a kilometer of LED strips. For this special occasion several artists had developed patterns for this massive LED display, animating the parties happening every night in front of this build.
To handle the dusty environment, a Toughbook was running the pyramid’s main code, which was rendering the animation frames to 24-bit bitmaps and sending them over UDP to the network. For each face of the pyramid, a $45 BeagleBone Black running a dedicated program was slicing the images into the individual panels. Finally, each panel composed of eight WS281x LED strips was driven by a Teensy 3.0 microcontroller, receiving the piece to display by USB from the BeagleBone. To power the pyramid, 5V 40A power supplies were used for the tall panels, 5V 30A power supplies for the smaller ones.
Unsurprisingly, many of the power supplies failed due to the heat and dust. The adhesive holding the LED strips also failed, and some screw terminals rattled loose from the 25KW sound system, requiring constant maintenance. Nevertheless, the sixteen thousand LEDs sure made quite an impression.
If anyone attending Burning Man managed to capture video of this thing in action we’d love to see it. Leave a link in the comments.
[Terry] wanted to come up with a little electronics project for his kids, and also came up with something to keep the wife happy. It’s an adorable 14-segment love letter, pieced together with some leftover LED displays and a bit of solder.
There isn’t a microcontroller anywhere to be seen in this project – all the illuminated segments are tied to a switch, and aside from a few resistors there isn’t much to this circuit. The simplicity means it’s a great way for [Terry] to get his kids involved in electronics.
If you’re wondering why [Terry] didn’t throw multiple Arduinos, shift registers, or LED drivers into the build, consider this: sometimes segment displays can be static. The time circuit prop from Back to the Future (but not this modern recreation) was wired up in a similar manner, as only a few specific dates needed to be displayed. Either way, we’re thinking good on [Terry] for introducing his kids to a soldering iron and doing something special for his lady friend.
Registering a mutant vehicle at the Burning Man Department of Mutant Vehicles (DMV) is rough. To be allowed to operate at night, wacky rolling creations have to have a certain degree of lighting presence. This keeps vehicles from blending into the scenery. Unfortunately Mirage 1.0 was built specifically with this in mind, using reflective surfaces to turn a van into a semi-invisible shiny slab. Not even EL wire, an illuminated dance floor, and spot lights could placate the DMV. The solution? Wrap the entire friggen vehicle in a netting of 4,000 LEDs! Take that officials!
Most of the hardware is Phillips display stuff, digital LED fixture controllers are used to interpret HDMI data and then pipe out color data to addressed chains. All this mapping and addressing means that the entire setup functions like a 168×24 pixel monitor. Split chains of LEDs also happen to allow the crew to operate the doors and get in and out of the vehicle.
The underlying car was built on the same sort of principal that hid the wheels of Skywalker’s landspeeder, only in this case the idea was to cover an entire car with mylar and mirror. An interesting side effect of this mirror wrapping is that a sheen of desert dust helps reflect the ambient LED light quite well, blurring pixel colors together. It sort of makes us wonder about picking up a bucket of Mylar for some of our spaced out displays.
The Mirage crew has plans for next year, and have videos of several ideas on the site (portions of the test videos are NSFW). Check out the video of Mirage 2.0 in action after the jump! Thanks [erland]!
Continue reading “Mirage 2.0 Lights up the desert with 4,024 LEDs”
What do you do if you see a bunch of 14-segment LED displays for sale for a penny a piece? [Fritzler], when faced with that conundrum did what any of us would do – he bought 64 14-segment displays and built a huge 16×4 alphanumeric display (German, here’s the translation).
[Fritzler] found a cache of old East German 14-segment displays for €0.01 at electrobi.de (don’t bother, they’re out of stock), and the only thing he could think of was building a gigantic display. He used ULN2803 Darlington drivers for each LED module, but there was still the issue of controlling the entire display.
For that, [Fritzler] decided to make his 16×4 use the same protocol as the Hitachi HD44780 LCD controller. This meant [Fritzler] could wire up his gigantic, power-hungry display to a microcontroller as if it were a simple LCD display.
An amazing amount of work went in to the creation of this display, as evidenced by a pair of pictures showing what [Fritzler] had to solder.
Thanks [freax] for sending this one in.
After [Ch00f] got his hands on an 8×8 LED display, he didn’t make a 64-pixel video game or VU meter. He made a laser doodler, allowing him to draw on this display with only a laser pointer.
Using LEDs as light sensors is nothing new; [Forrest Mims III] discovered that LEDs can also detect light way back in the late 60s. [Ch00f] played around with this concept before creating a circuit that uses an LED as both a light emitter and sensor that reacts to the ambient brightness.
[Ch00f]’s laser doodler takes this phenomena and applies it to an Adafruit bicolor LED matrix. When a light shines on an individual pixel in the display, the ATMega48 senses the current and turns that pixel on. Since this these pixels have two colors, [Ch00f] used a latch circuit and a button to cycle between what color the ‘Mega writes to the display.
In the video after the break, [Ch00f] shows off his display by having the LEDs light up in response to a laser pointer. It may be a bit small, but we can see a lot of potential for something like this as a gigantic art installation.
Continue reading “Writing on LEDs with a laser pointer”