Senior college projects are the culmination of years of theoretical learning finally put into practice. For many students they are their first experience of doing some proper, real world engineering. [Melangeaddict] chose to take on a persistence of vision display for his final project, and learned plenty along the way.
The display consists of a row of 48 RGB LEDs mounted on an arm capable of rotating a full 360 degrees, with a simple paper diffuser. This arm is spun up by a belt drive from an electric motor at significant rotational speed, so getting close to this machine is quite inadvisable. Thanks to quality bearings and a careful build, rotating resistance is minimal. An infrared LED is mounted on the frame, and the light picked up by a photodiode on the rotating arm, allowing the images to remain fixed in space without drifting over time. Images can be loaded to the display wirelessly over a Bluetooth interface, which was quite advanced for a DIY project in 2011.
We’re a fan of the 360 degree approach to POV displays, and with the right rotational speed and fast data rates, it would be possible to get some seriously high resolution out of the device. Just be careful not to stick your hands in the mechanism.
There’s a deep well to explore when it comes to POV displays, from three-dimensional builds to vibrating flexible setups. Video after the break.
Wonder if it works? WOuld have been nice to see it in action.
I managed to find a video of it running on the same channel – the camera isn’t playing nice with the POV effect but it gets the point across – https://www.youtube.com/watch?v=8w68AVkoZC8
In retrospect, we should have found another camera with a better refresh rate, but it was the end of the semester, and we were all eager to go home for the winter holidays.
As with almost all POV’s, it looked much nicer in person.
This is almost always true! We should do an “Ask Hackaday” on tips and tricks for photographing POV toys. Long exposures work great for stills, but for video?
Steve Mould does a good job at explaining this https://youtu.be/C-V1uXeyGmg
Better yet would be to use a still camera with a shutter speed of around half of the spin rate.
If you visit their channel on YouTube, there’s a video of it in action: https://www.youtube.com/watch?v=o7oOL0CvIfc
It, and the video linked here, were both posted some 7 years ago though, so the project is probably long since abandoned. POV is always cool, although at the end of the video of it in action, it shows it spinning with the room lights on and… I’d be a little hesitant to stand next to that thing!
YES! At full speed the thing was really spinning at a good clip. During the actual demo we built a ‘cage’ with plexiglass around it to keep people from getting too close.
It’s from 2011, but if you go to the member’s videos, you find: https://www.youtube.com/watch?v=8w68AVkoZC8 https://www.youtube.com/watch?v=w_DCqO-TkQU and https://www.youtube.com/watch?v=o7oOL0CvIfc
Glad you found the other videos! We had a ton of fun building the thing.
This looks like from 2011 and has no actual demonstration. Nice, but not really that newsworthy. Anything more recent?
I made a couple of videos showing it in action, but I guess they couldn’t embed more than one vid? I dunno. Here’s a better one showing it in action in the basement:
https://www.youtube.com/watch?v=o7oOL0CvIfc
It worked pretty well, having seen it in person. Decent persistence for the budget, time, and work of some college students. When they showed it in public, they had it caged off with some plexi I believe.
We did. In fact, if you look to the left of our poster in the background you can see it.