More POV Fan Message Hacking

August 27, 2011 by Mike Szczys 25 Comments

[Zach’s] company is all about the safety and to reinforce those ideals they handed out POV display fans to each employee. “Being Safe is Cool”, get it? Gimmicky… yes, but now [Zach’s] got a tiny little POV fan to hack. Although he may not have known it, this isn’t the first time we’ve seen this hardware. These fans were handed out as a promotion at Black Hat a couple of years ago and prompted some reverse engineering action. The message is stored on an EEPROM and there’s even a female programming header that makes it easy to write reflash it with your own messages if you know how to craft the data.

This is where the two products diverge. The older project uses a serial connection and PonyProg to dump and data. [Zach] first tried using his Bus Pirate to dump the data but after having no success he grabbed his Arduino and managed to get the job done. Once the message encoding protocol was worked out, he wrote a sketch to flash the EEPROM. So if you can get your hands on one of these the work has already been done. See [Zach’s] custom messages in the video after the break.

But we’d like to see this taken to the next level. How about a wall-mounted device that waits for something, like an incoming email or tweet, then spins up the fan to display it?

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Persistence Of Vision Helicopter Blades With RGB LEDs

August 12, 2011 by Brian Benchoff 17 Comments

A user named [BOcnc] on the rcgroups forums just posted his RGB POV helicopter blades.

The two blades are attached to the heli just as any other whirlygig. The electronics, though, are mounted underneath the blade with a battery pack. We covered a build last year that demonstrated weight added to a spinning blade won’t tear everything apart, but that build used only blue LEDs. This build is full color and makes us feel like we’re living in a cyberpunk future populated by Recognizers and Daft Punk.

The images are stored on an SD card that receives data from a USB port. The microcontroller is a PIC32, and from what we can assume from the schematics, the RPM of the blades is measured by an on-board hall effect sensor (don’t quote us on that, though). There’s no hope of a commercial release from [BOcnc], though. He can’t find anyone to manufacture the blades, and the entire build was too expensive. It sure looks pretty though, so check out the video of it after the break.

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Race Car POV LED Displays

July 15, 2011 by Mike Nathan 26 Comments

race_car_pov

Last year, when [Alex] was asked by his friend [Martin] to help him out with building some LED POV modules for a race car, his response was a enthusiastic “YES!”

[Martin’s] goal was to involve fans more deeply in the race, so he decided that the POV modules would carry messages from fans on-board, printing them in the night as the race cars screamed around the track. The pair started prototyping and testing a design, wrapping things up shortly before this year’s 24 hours of Nürburgring.

The modules consist of an Arduino-compatible AVR, a GPS module, a 16-LED light bar, and the circuitry for driving the LEDs. While most of the components are pretty standard fare, the we don’t often see a GPS sensor built into a POV display. [Alex] says that the sensor is used to calculate the speed of the cars, ensuring a uniform font size.

They took their LED displays to the 24 hours of Nürburgring, where they were invited by Audi to install the modules on a pair of R8 Le Mans race cars. As you can see by the pictures on his blog and Flickr set, the POV units worked out nicely without having to stretch the camera exposure times too far.

If you’ re interested to hear a bit more about how the displays were built, check out this entry in[Alex’s] blog, where he goes through some additional details.

Update:[Alex] pointed us to the videos!

Slick 16-segment POV Hard Drive Clock

July 10, 2011 by Mike Nathan 20 Comments

Hackaday reader [svofski] sent in a fantastic looking hard drive-based POV clock (Google Translation) created by a maker in the Sichuan province of China. The clock, like the one [svofski] built, relies on LEDs placed behind the spinning platter to create the POV effect.

Quite a few carefully placed cuts have been made to the platter, which make up the segments required to display both numbers and letters of the alphabet. This isn’t a simple 16-segment POV display however. The font uses a lot of sharp edges and odd segment lengths, so we’re guessing that quite a bit of care was taken in the production of this clock.

You can see a demonstration of the clock in the video embedded below, which shows off its ability to display numbers, text, as well as a handful of simple patterns. It looks like there are some details available on the designer’s site, however it is all in Chinese, and Google’s translation is questionable at best. If only we knew someone that could give us a hand with deciphering the inner-workings of this clock…

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Puppy POV: Four-legged Persistence Of Vision Display

June 14, 2011 by Mike Nathan 7 Comments

puppy_pov

We see lots of persistence of vision projects around here, but we can’t recall any that involve a POV display facilitated by a living, breathing animal (humans aside, if you want to picky). [Michael] has a Miniature Pinscher that just loves to run and run…and run…in circles. Since she generally runs very fast and in large curves, he thought she would make a great POV device.

He has a small fleece “jacket” for his dog, and on it, he mounted a Lilypad Arduino, the associated power supply, and five bright white LEDs. Naturally, conductive thread was used to wire up the circuit, and after a bit of trial and error, things came together nicely.

With the vest complete, [Michael] unleashed his dog at the park, letting her run to her heart’s content. All the while, her vest was writing out [Cory Doctorow’s] “Makers” while he snapped some pictures.

We can’t think of a more appropriate text to write with LEDs in the night, but in the spirit of the book, we were hoping to see a circuit diagram or the project’s code posted. If he shares it, perhaps we could convince [Cory Doctorow] to run about the park in a vest, writing out [Michael’s] code in bright white LEDs!

Small POV Device Shows Off Some Big Features

April 26, 2011 by Mike Szczys 21 Comments

We’ve already added the components needed to build [Rucalgary’s] tiny POV device to our next parts order. The little device sets a new standard for tiny persistence of vision boards. Instead of relying on the user to find the best speed and timing for swinging the board around, [Rucalgary] used an accelerometer. This is the point at which we’d usually groan because of the cost of accelerometers. We’re still groaning but this time it’s for a different reason.

The accelerometer used here is a Freescale MMA7660. It’s an i2c device at a super low cost of less than $1.50. The reason we’re still groaning is that it comes in a DFN-10 package that is a bit harder to solder than SOIC, but if you’ve got patience and a good iron it can be done. An ATmega48 drives the device, with 8 LEDs and one button for input. On the back of the board there’s a holder for a CR2032 coin cell battery and a female SIL pin header for programming the device.

Check out the video demonstration embedded after the break. We love it that the message spells and aligns correct no matter which way the little board is waved.

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Build A Spinning POV In A Day

April 19, 2011 by Mike Szczys 10 Comments

We love spinning POV displays but have yet to build one to call our very own. This project might be the one that we end up building. It’s looks good and it’s the only persistence of vision display that comes to mind which can be built in twelve hours.

The spinning is taken care of by a PC fan. This actually helps with some of the calculations as this fan spins at a know RPM. That information, along with a bit of geometry, can be used to calculate the timer interrupts for syncing the display. A reference point for this device is provided by an IR receiver/emitter pair which is easy to wire up since you already need a voltage source for the fan itself. The rest of the hardware is pretty common: a battery holder is centered on the axis for proper weight distribution and protoboard houses the components such as a PIC 18F252, 74LS373 data latches, and the LEDs themselves. The circuit is wire-wrapped, and works like a charm as evidenced in the clip after the break.

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