We’re not exactly trend setters when it comes to wardrobe. And so the recent revival of the bow tie as an accepted dress item confounds us. We’re even more confused by [Arichter’s] LED bow tie. Sure, the hobby electronics part of it is a win… but when it comes to fashion is he making fun of the bow tie wearers, or setting a new standard?
The tie is made of three PCBs, which lets the wings sit on a bit different plane than the center. He populated the boards with about 100 RGB LED modules which he desoldered from a couple of meters of LED strip. They draw a lot of juice and to supply that he uses a boost converter. A standard Arduino UNO board controls the lights.
If you’re still sold on the bow tie form factor we’d like to direct your attention to this long-tie version. It doesn’t just show patterns, but plays a wicked game of Tetris with you as the game board.
Timing is everything and that’s why most communication protocols require a very accurate clock source. The WS2811 LED strip controllers are no different. But [Danny] figured out a way to drive them reliably with an 8MHz clock source.
The WS2811 has become one of the most popular controllers for RGB pixels and strips alike. We’ve seen several hacks used to address them, including the 16MHz AVR technique that inspired [Danny] to take on this project. He planned to use that library but the 25-day shipping time for a 16MHz crystal drove home to invent a way to use the internal oscillator instead.
The gist of the hack is that he wrote assembly code to handle pairs of binary bit values. With a code block for each of the four possible combinations in hand he had to find a way to craft the conditional jumps to preserve accurate timing. After hitting the wall trying to solve this puzzle by hand he wrote a C++ program to solve it for home. The proof is in this video which shows one chip driving multiple Larson scanners on a single strip.
Continue reading “WS2811 can be addressed at 800kHz using a 8MHz clock”
[Paul] took this LED display along with him to Maker Faire. To give it some interactivity he figured out a way to make it play live video. It is also activated using some stomp actuators built from piezo speaker elements and rubber floor mats.
This moves his original project in new directions. Back in February he was showing off the RGB LED strip display. He had it playing video but that was all dependent on using previously processed files. This upgrade uses a BeagleBone Black (the newest rendition of the ARM-based development board). [Paul] had tried using a Raspberry Pi board but had trouble with the webcam (mounted above the LED display) dropping frames. With the new board he is able to use the Video4Linux API to capture 30 frames per second and push them out to the display.
So far he’s had five out of the 1920 LEDs die on him. This shows off a couple of good things about using strips like this. A dead pixel doesn’t affect its neighbors. And replacement is as easy as cutting the ribbon on either side of the bad component, then soldering a new segment in place.
Sometimes a pair of extremely similar builds hit the Hackaday tip line within hours of each other. We’re not one to play favorites, so here’s two projects that put RGB LED strips in a desk and workbench.
[Charles] over at The Makers Workbench has long needed a lighting solution for his workspace. Flourescent lights are alright, but for real geek cred nothing but LED strips will do. He picked up an RGB strip on Amazon for $20 and now has a lighting solution that’s able to change colors above his workstation. Check out the video of his RGB workbench rave.
A computer desk is a workbench too, right? [Will] had the idea of letting people on the Internet control the lighting color of his desk. He’s asking people to head over to this site and asking people to schedule the color of his desk for an entire day. A Raspi pulls each day’s color off the server. With a few transistors, an RGB strip, a custom shield, and faking three PWM channels, [Will] has a new color at his desk every day.
Building RGB LED displays is one of the most interesting programming and engineering challenges we see here on Hackaday. Not only do the creators of large displays and LED cubes have to deal with the power requirements of driving a whole bunch of LEDs, but there’s also the issue of getting the frame rate high enough to display video. It’s a non-trivial task, but [Paul Stoffregen] has an interesting solution. He wrote an LED strip library that can control eight meter-long LED strips that can also be used on daisy chained Teensy 3.0 microcontrollers for really large displays.
[Paul]’s LED library works with LED strips based on the WS2811 LED controller IC. These chips are the most common controller chips for the individually controllable LED strips you can find at Adafruit or hundreds of Chinese resellers. The library requires DMA transfer to display images, so if you’re looking to build a ginormous RGB LED display, you might want to pick up a few of [Paul]’s Teensy 3.0 boards
[Paul] also created a Processing app that takes a video file and turns it into serial data for his LED strip library. You can check out a video of this app, library, and a 60×32 RGB LED display after the break.
Continue reading “Building huge displays with LED strips”
[4RM4] over at the Stuttgart hackerspace Shackspace ran into a guy selling individually addressable RGB LED strips when he attended the 29th Chaos Communication Congress last December. He had a Raspberry Pi with him, and after a little bit of work he rigged up an LED display that wrapped around a trash can. A respectable hack, but not quite ready for prime time.
After getting back to the Shackspace, [4RM4] decided to go in a more classic direction by building an RGB Snake clone. A few neat features were implemented like a high score list, a free play bot, and a clock.
To control his pixel-munching snake, [4RM4] used a Wii Nunchuck controller hooked up to the Raspberry Pi’s GPIO pins. It looks like a whole lot of fun, and given the absurdly high scores shown in the video after the break, it looks like this build is getting a lot of use at the Shackspace.
Continue reading “Raspi-controlled RGB LED strip display”
Sure, it’s time to get the countdown clocks ready to ring in the new year, but why limit it to just one night? If you end up building a six-foot digital display you can count down trivial events; like the remaining seconds of freedom before you have to pimp yourself out in that drab cubicle.
This seven-segment display is homemade and boasts six full-sized digits and two smaller digits with each pair separated by colons. You have probably already guessed that the construction was greatly simplified by using LED strips rather than individual components. This is part of the reason for the size of the display. The strips can be cut, but only down to a minimum of 3 LEDs per segment. That explains the small digits, with their larger siblings doubled in size. But there is a benefit to this constraint, it means that current limiting is already taken care of for you.
The main assembly is a wooden frame surrounding two polycarbonate sheets. The LED strips are sandwiched between those sheets, with segment and digit driver buses exiting a one point on the side. The build doesn’t detail a driver for the display but it shouldn’t be hard to find a multiplexing example that will serve the purpose.