[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.
[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.
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.
[Akeeh] posted something to our flickr pool that caught our eye. The image was a rotating POV display, playing pong. We followed through the links and found this very well done rotating pov display. The construction is quite nice, showing multiple colors and smooth motion. there’s a little bit of wiggle even though it has a custom round pcb. Maybe a little better counter weight would help with that. The idea isn’t new, but it is good looking and elegantly made.
We pretty much don’t know anything about this POV device other than it uses 96 LEDs. We’ve seen POVs with more LEDs, but usually they aren’t packed in so tight. This thing looks almost capable of displaying low res movies. Wouldn’t this thing be cool, and probably dangerous, in a hat?
[Mario Mauerer] and friends were commissioned to build this 2m persistence of vision display (translated) for a party (in a hight-voltage lab no less). Dubbed “Display from Hell”, it uses 100 blue SMD LEDs to generate the POV images. They’re connected to an ATMega64 via shift registers. Their target speed is 600rpm for a flicker free image, which means the propeller tips are moving at 140mph. The board can be updated wirelessly via IRDA and plans for adding SD storage are in place. You have to see and HEAR this thing in the video embedded below. Read the rest of this entry »
[Rory Hyde] and [Scott Mitchell] are exploring several projects that add more information to public spaces. The first is the Spoke-o-dometer a persistence of vision device that can display bicycle speed and distance traveled. To develop the device, they first bought a few POV kits to test out. They decided to build their version using an Arduino. Once they had the display proof of concept working, they added a hall effect sensor like the SpokePOV so they could determine speed and orient the display. Check out their project site for plenty of example code and development details.
