Persistence of vision projects were once all the rage, judging by a quick review of the literature here on Hackaday. They’ve tapered off a bit lately, but this impressive full-color globe display might just kick-start some new POV projects.
Built as a final project for an EE course, [Evan] and [Kyle]’s project is more about the control electronics and programming than the mechanical end of the build. Still, spinning a 12″ ring of 1/4″ thick acrylic with a strip of APA102 LEDs glued to the edge takes some thoughtful engineering. While the build appears sturdy, [Evan] does admit to a bit of wobble under full steam, which was addressed by adding some weight to the rig. We wonder if mounting half the LEDs on each side of the ring to balance the forces wouldn’t have worked better. True, it would have complicated the coding for the display, but maybe that would have been good for extra points. In any case, the display turned out well and the quality of the images is great. And as an aside: how awesome is it that we live at a time when you can order a six-circuit slip-ring for a project like this for less than $20?
It’s the end of the semester and we love seeing the final projects that have just made it across the finish line. This globe is one, yesterday we saw a voice-controlled digital eye exam, and if you have or know of a final project, don’t forget send us the link!
If POV globes are your thing, be sure to set the Hackaday WABAC machine a few years and check out this Death Star design from 2012 or this globe from 2010.
Accidents happen – but the awesome quotes you all sent in for Week 15 of the Caption CERN Contest were no accident. A huge thank you for our biggest week yet! The scientists in this week’s image are definitely cleaning up after some type of nasty accident. At first blush it looks like an electrical problem in the coils of what appears to be part of a beam line. With all that soot and radiation dangers to boot, only the photographer and the people in the image know for sure!
- “This is the second server these idiots have fried! What the hell’s a Hulu, and why are they trying to watch Gilligan’s Island with it?” Thanks to some unplanned quantum tunneling, Berners-Lee was even further ahead of his time than he thought” – [The Green Gentleman] (Two weeks in a row!)
- “I found the bug. Who gets to tell Joe he’s sterile?”- [jonsmirl]
- “‘I told the Captain that she couldn’t take any more’ – Scotty” – [md_reeves]
The winner for this week is [Mr. mmWave] himself, [Tony Long] with “Hardware Accelerator moto – Fail Fast, Fail Often. Also applies to Accelerator Hardware.” [Tony] will be debugging his next microwave mm band ham radio with a Logic Pirate From The Hackaday Store! Congratulations [Tony]!
Week 16: This is not your father’s POV Display!
Scientists at CERN have come up with some amazing science advancements. They’ve also needed ways to display the data they collect. This image may depict some incredible new way to display data collected from a high power physics experiment – or it could be a scientist’s project for the CERN science fair. We may never know.
The album is titled CHAMBRE A ETINCELLES DANS EXPO TECHNOL, which roughly translates to “Sparks in the technology expo room”. The lines traveling between the three horizontal display devices definitely appear to be aligned. Are they sparks of electricity? You tell us!
Last week’s prize was a Logic Pirate. This week we’re giving away a Bus Pirate from The Hackaday Store.
Add your humorous caption as a comment to this project log. Make sure you’re commenting on this contest log, not on the contest itself.
As always, if you actually have information about the image or the people in it, let CERN know on the original image discussion page.
Wanting to showcase their USB LED strip controller, the folks at Maniacal Labs built a POV LED stick this weekend. Yes, it’s pretty much the same as any other POV LED display you’ve seen; set a camera for a long exposure, wave the POV light stick around, and get a cool pixely image in mid-air. This build is a little different, though: it’s controlled over WiFi with a Raspberry Pi connected to a WiFi network.
The USB LED strip controller in question is the AllPixel, a small board that controls NeoPixels, WS2801, LDP8806, and a bunch of other LED strip controllers over USB. The Stick used for this project consisted of two meters of LPD8806 LEDs, giving 96 pixels of horizontal resolution. A big battery and Raspberry Pi rounds out the rest of the electronics.
Building a LED POV display isn’t that much different from building a LED matrix display; all you have to do is break up the image into individual columns and display them sequentially. To do this, the Maniacal Labs folks whipped up a LEDPOV class that does just that. To get the images, just open the shutter on a camera, wave the stick around, and if you get it right, you’ll have a great pixely image of nyan cat or the rainbow wrencher.
[Andrew] wrote in with a new take on the classic persistence of vision bike spoke hack. While many of these POV setups use custom PCBs and discrete LEDs, [Andrew]’s design uses readily available off-the-shelf components: WS2811 LED strips, an Arduino, an Invensense IMU breakout board, and some small LiPo batteries.
[Andrew] also implemented a clever method of controlling his lights. His code detects when the rider taps the brakes in certain patterns, which allows changing between different light patterns. He does note that this method isn’t incredibly reliable due to some issues with his IMU, so now he senses when the rider taps on the handlebars as well.
If you want to build your own bike POV setup, you’re in luck. [Andrew] wrote up detailed instructions that outline the entire build process. He also provides links to sources for each part to make building your own setup even easier. His design is pretty affordable too, coming in at just under $50 per wheel. Check out a video of [Andrew]’s setup in action after the break.
Continue reading “Simple POV Bike Effects with WS2811 Strips”
[Sholto] hacked together this ultra low-budget spinning display. He calls it a zoetrope, but we think it’s actually an LED based Persistence Of Vision (POV) affair. We’ve seen plenty of POV devices in the past, but this one proves that a hack doesn’t have to be expensive or pretty to work!
The major parts of the POV display were things that [Sholto] had lying around. A couple of candy tins, a simple brushed hobby motor, an Arduino Pro Mini, 7 green LEDs, and an old hall effect sensor were all that were required. Fancy displays might use commercial slip rings to transfer power, but [Sholto] made it work on the cheap!
The two tins provide a base for the display and the negative supply for the Arduino. The tins are soldered together and insulated from the motor, which is hot glued into the lower tin. A paper clip contacts the inside of the lid, making the entire assembly a slip ring for the negative side of the Arduino’s power supply. Some copper braid rubbing on the motor’s metal case forms the positive side.
[Sholto] chose his resistors to slightly overdrive his green LEDs. This makes the display appear brighter in POV use. During normal operation, the LEDs won’t be driven long enough to cause damage. If the software locks up with LEDs on though, all bets are off!
[Sholto] includes software for a pretty darn cool looking “saw wave” demo, and a simple numeric display. With a bit more work this could make a pretty cool POV clock, at least for as long as the motor brushes hold up!
Continue reading “POV Display Does it on the Cheap”
[Paul Stoffregen], creator of the Teensy series of dev boards, previously implemented a six-axis joystick for Teensyduino, the Arduino library for the Teensy. He had originally tried 8 axes, but a few problems cropped up, deadlines approached, and he left it as is. A few recent projects gave him some insight into how to implement a joystick with more than six axes as a USB HID device, so he started looking at how to read an improbable amount of pots and buttons for a USB joystick.
So far, the biggest problem is figuring out what software can actually use an HID joystick with this many controls. The answer to that question is none. The Linux-based jstest-gtk is able to read 6+17 pots, the four hat switches, but only 64 of the 128 buttons. A user on the Teensy forums, [Pointy], has been working on his own joystick test app that works on
Linux Windows, but testing the joystick on Windows is an exercise in futility for reasons no one can figure out.
As for why anyone would want a six-axis, 17-slider, 128-button joystick, think about this: with this much control, it would be relatively simple to build the MIDI controller to end all MIDI controllers, or a cockpit simulator for everything from a C172, 737, to a Kerbal interplanetary cruiser. That’s an impressive amount of control, and all from a $20 Teensy dev board.
Further testing of this Teensy joystick is desperately needed, so if you’re able to help out drop a note in the forum thread.
Persistence of vision displays are always cool, although we must admit this one looks like it could very well explode at high speeds…
Safety concerns aside, this desk fan based display provides a great starting point for learning about making POV displays. It makes use of an old cellphone battery, an ATmega8, some LEDs, Veroboard, assorted wires and solder and of course, a high-speed desk fan.
[shparvez001] also provides the full code on his blog for the project, making it very easy to replicate. Though we might also suggest you keep it small enough that the original fan cage still fits on top.
From an aesthetic point of view, the display looks fine in the dark — but when the lights are on you might get some odd looks. We can see this project being greatly improved by mounting the LEDs through one of the fan blades, and the control electronics on the back side of the other blades. Maybe throw in some wireless charging for the battery while the fan is off too?
Anyway, stick around after the break to see the display in action. If you want a more permanent fan POV try adding display hardware to a ceiling unit.
Continue reading “POV Display with an Element of Danger”