[Ben] told us about his POV globe yesterday. We took a look and saw just one photo and the code with no real explanation of his project. He certainly set to work over night and now we see all the goodies we look for in a great build log. He even threw the Hackaday logo up for our enjoyment. His build is well executed and he found some creative ways around the common problems in these projects. We take a closer look after the break. Read the rest of this entry »
Hacking with Gum got their hands on one of the persistence of vision display fans that Cenzic was giving away at Blackhat this year. It’s not the biggest fan-based POV display we’ve seen but it’s still a fun device to tinker with. They hacked into the EEPROM on the device in order to change the message the fan displayed.
This is very similar to the other EEPROM reading/writing we’ve seen recently. Hacking with Gum read the data off of the EEPROM and then disassembled it to discover how the message data is stored on the chip. This was made easier by noting the messages displayed when the fan is running. The first byte of data shows the number of words in the message, then each chunk of word data is preceded by one byte that represents the number of letters in that work. Data length was calculated based on the number of pixels in each display character. Once he knew the data-storage scheme, it was just a matter of formatting his own messages in the same way and overwriting the chip.
This is a great write-up if you’re looking for a primer on reverse engineering an unknown hardware system. If you had fun trying out our barcodechallenges perhaps deciphering EEPROM data from a simple device should be your next quest.
[Jared] sent us a feature he posted involving time-lapse photography and an LED. Using a custom built aparatus an LED is moved on two axis’ during a long exposure of around thirty seconds. The frame is wood and PVC with two gearhead motors powered by AA batteries to provide the locomotion. The LED is powered by a 3v button cell and automatically transitions through different colors.
We’ve brought you an HDD clock in the past, but [mb1988] tried to bring his project to another level by fully documenting it (in Polish). Inspired by [dzgdzzh]’s version of the same invention, [mb1988] decided to reverse engineer it (as well as make a few changes) and base it on the powerful ATmega128. Since this clock, along with most HDD clocks, can only display solid lines of radii, it cannot be used to display text. However, color schemes and animations can be toggled using a remote control. The housing itself is also pretty impressive. The back part of the enclosure was molded out of Rayobond, while the front was simply the original HDD case but spray-painted black and etched with some original artwork. The source code, schematics, and PCB layouts are freely available to download on the project’s thread, but you will have to login to the forum to access them.
This bit of nostalgia really caught our attention. A german hacker or “inventor” as we were called back then, came up with this interesting concept. He would project an image on to the moving blades of an Autogiro, relying on the POV effect to make it appear complete. While this is not the same system of utilizing POV that we currently use, it relies on the same principles. It looks like he’s hanging the projector or “magic lantern” from below the Autogiro, using the length of the rope to hang it as a focusing system. Were this to have actually gone into production, it probably would have really freaked people out. If only he had had access to something along the lines of the ceiling fan POV system.
[thanks itay]
[update: Why didn't we look around for this earlier. It was brought up in the comments, there is in fact a POV system for R/C helis. http://www.nightgraphix.de (translated)]
We know some of you are getting sick of POV projects, but this one was just so cool, we couldn’t resist. [UncleBone] thought POVs were pretty cool, and wondered if he could use one on his ceiling fan. It would have been a breeze just to toss something like the RGBike POV on there and call it finished, but he designed his own. Opting to blow away the norm of using a single row of LEDs, he chose to do 5 different rows of LEDs, one for each blade. The whole thing is controlled by an Arduino, with a spreadsheet for image manipulating. Unfortunately, we don’t see any source files for the project available. Maybe he’ll put them on there if we ask really nicely. If he could get it playing animations, we would just chill and watch it for hours.
[Hazard] wanted a full color POV display for his bike wheel. Adafruit’s SpokePOV is single color and Monkeylectric’s original version didn’t display images. He also balked at the cost and decided to manufacture his own version. It uses 16 RGB LEDs on a single layer board he manufactured himself. It’s an entirely through-hole design to make assembly easy. It uses a hall effect sensor to synchronize the image display. The two main components are an ATmega328p microcontroller, which should make it Arduino compatible, and a TLC5940 PWM LED driver. It’s a very well documented build and certainly a good looking effect.
[Jon Stanley] has a nice write up on a POV propellor clock powered by a PIC microcontroller. He improved on the original design by [Bob Blick]. Jon tried a few different methods of powering the spinning circuit, some of which could be handy for other projects. As a double plus good bonus, schematics and code are all linked on the site. This clock would look nice and sinister sitting on any mad scientist’s dresser.
[Hazard] is designing this open source POV system for bikes. With the recent release of Monkey Electric’s m464q, [Hazard] was inspired. He found the price tag of roughly $2,000 to be way too much though. He is designing his own and taking us along for the trip. He hasn’t quite reached the Monkey Electric level of features, but he does have image display and simple animation. He encourages others to join him in improving the design. He notes that the image on the back side of the wheel is mirrored, so text would be backwards. Maybe he can pick some tips up from this old project.
Here’s another POV project for you. It’s pretty big, at 1 meter in diameter, not quite as large as the stupidly huge one. What is interesting about this display is that it has a dual motor set up. The original motor didn’t quite have the power to get the display up to the required speed. A second one was added as the shaft of the rotor. Yes, one motor is actually spinning another motor that is spinning the display. Well, it’s hard to tell from the description. The original motor might be completely unused, but left in place.
