[Jason] used a strip of 142 Adafruit LPD8806 Addressable RGB LEDs to create the StarGate Eggbeater persistence of vision display. The LED strips are controlled by an Arduino Mega, which is used to control the strip and provides 21 bit color control for each LED. The strip is housed into a ring-shaped tube which is mounted onto a rod and bearing to allow it to spin. A 1/4 HP motor is used to spin the ring at 250 RPM creating the POV effect.
One issue when controlling a spinning object is making electrical connections to a spinning object. The LPD8806 requires four connections: power, ground, clock, and data. To make the connections, [Jason] used a MOOG Slip Ring. This allows for the four connections to be made while the ring spins at 250 RPM.
Of course POV demos need videos, so check one out the “boss program” video after the break.
Continue reading “StarGate Eggbeater”
Watching Big Buck Bunny on a spinning POV display is pretty impressive. Sure, the circular display area cuts off some of the picture, but otherwise it looks fantastic. This POV display is based on a Gumstix board. It runs embedded Linux which makes video playback rather easy. But translating each frame to the round display is another story.
The device is the result of a course project at Telecom ParisTech. [Félix], [Sylvain], and [Jérémy] used an FPGA to do the pixel mapping. This uses an encoder wheel (rather than a traditional hall effect sensor) to ascertain the blade’s position. The sensor that monitors the disc sends quadrature encoded pulses which result in 10-bit position data. The FPGA uses that data to calculate where each LED falls in its arc, then looks up the pixel color for that position. It’s not the largest POV display we’ve seen, but it certainly has the very best RGB resolution by far.
Continue reading “Full-color video on a spinning POV display”
We’ve seen our fair share of remote-controlled planes turned into UAVs and FPV platforms, but the Techpod is the first airplane we’ve seen specifically designed to be used as a camera-equipped robotic airplane.
The Techpod is the brainchild of [Wayne Garris]. He has been flying camera-equipped FPV airplanes for a while now, but recently realized the current offerings of remote control planes didn’t match his needs. [Wayne] decided to design his own plane specifically designed with a pan/tilt camera mount in the nose.
[Wayne]’s prototype was designed with some very fancy aeronautical design software packages and milled out of foam. From the videos after the break, we can see the Techpod flies beautifully, but needs the Kickstarter community to bring his model to the masses.
The specs for the Techpod put it up there with other high-performances FPV and UAV models; with its 102 inch (2590 mm) wingspan and a pair of batteries wired in parallel, the Techpod can stay aloft transmitting video for up to one hour.
Video of the plane in action after the break.
Continue reading “RC plane made specifically for UAVs”
Being an intern a Texas Instruments isn’t all fun and games, but from [George], [Valerie], and [Ryan]’s TI intern design project, it sure looks like it. They built a persistence of vision display for a bicycle using the ever popular MSP430 Launchpad board.
The team of interns created a POV display by combining the power of the TI Launchpad with a row of 32 RGB LEDs soldered onto a booster pack. Once the whole circuit is fastened securely to the bike wheel, a hall effect sensor mounted to the bike frame allows the MSP430 to detect how fast it is going. From there, it’s just a matter of flashing LEDs at the right time to create a stationary display inside a rotating wheel.
Although the display will theoretically work with just one Launchpad/Booster pack combo, the team decided to use three of these circuits, totaling 96 LEDs per wheel, to create a really nice RGB display. The video (available after the break) shows a little bit of flicker but this is an artifact of the camera. In real life, the POV bike wheel display is simply stunning.
Continue reading “POV bike wheels with the MSP430″
[Matt Pandina] has been documenting his build of a very nice light painting bar on his G+ page. His light painting bar has 64 RGB LEDs being driven by an ATmega328P and four TLC5940 chips. He wrote his own libraries to talk to the TLC5940 as well as his own libraries to pull images off of a MicroSD card. He also wrote a cross-platform program that automatically converts a directory of pngs to something the TLC5940s expect. He says the secret to getting his24-bit color correction looking right is gamma correction. It seems that when the LEDs were run too bright, he couldn’t get the colors quite right. In case you’re curious, those images are 15 inches tall!
You can follow along through his posts as he starts with just a few LEDs and slowly updates and grows it to the impressive state it is at currently.
Although [Serokoy] is not thrilled with the outcome of his Nipkow disk clock (translated), but we really enjoy it. It uses the Persistence of Vision concept to create a light display from a rotating disk.
We’ve come across a lot of rotating disk clocks. Several were based off of the platters of a hard drive, using a slit, or series of slits to make up the display. This Nipkow disk uses a similar technique but in a more general way. The series of holes arranged in a spiral pattern allows a grid of concentric rings to be used as pixels when the disk is spinning. The bottom portion of the disk is used as the display area. Each pixel is illuminated at just the right time by LEDs below in order to freeze that pixel in the viewer’s eye. The demo is a bit rough, and [Serokoy] mentions that the precision of the hole layout makes all the difference. He drilled these by hand in a CD which was spray painted matte black. Even though he used a computer to lay out and print a template, it took four tries to get a suitable disk.
The more we think about this one the more we like it. [Michael] built himself a wind-powered persistence-of-vision weather station. Okay, that sounds interesting, but he ups the ante when you find out what’s included in the system.
A stepper motor acts as the generator which powers the electronics. As we’ve seen before; if you spin the shaft of a stepper motor electricity is produced. [Michael] is actually spinning the housing of the motor, with the shaft mounted to the base that holds the weather station in place. This way, the electrical contacts are spinning along with the blades of the generator. By mounting all of the electronics on these blades he gets around the problem of transferring power onto a spinning platform.
A set of LEDs on the end of the blades display temperature and relative humidity readings. A hall effect sensor pulled form an old floppy drive syncs the display with the rotational speed. He’s even got a shunt system which keeps the input voltage at a safe level, and will act as a break in high winds to keep the rotors from spinning out of control. See what we mean? An interesting idea because a fantastic project when you build in features like these!