Death Stars were destroyed twice in the Star Wars movies and yet one still lives on in this 168 LED persistence of vision globe made by an MEng group at the University of Leeds in the UK. While Death Stars are in high demand, they mounted it on an axis tilted 23.4° (the same as the Earth) so that they can show the Earth overlaid with weather information, the ISS position, or a world clock.
More details are available on their system overview page but briefly: rotating inside and mounted on the axis is a Raspberry Pi sending either video or still images through its HDMI port to a custom made FPGA-based HDMI decoder board. That board then controls 14 LED driver boards mounted on a well-balanced aluminum ring. All that requires 75W which is passed through a four-phase commutator. Rotation speed is 300 RPM with a frame rate of 10 FPS and as you can see in the videos below, it works quite well.
This isn’t the first POV Death Star we’ve seen here. [Jason] made a smaller one using his own rotating PCB that can be described only as awesome.
[via Adafruit]
Oh, I know just where I’d put that in my home. I think these are great.
Somewhere safe were it can’t be accidentally touched during operation.
Or just put a glass dome around it like they did here? ;)
Note, when filming your POV globe, dont use your phone. use a real video camera where you can set the frame rate to lower than the rpm of the globe.
It was done on a DSLR which was the only thing I had at the time (other than a phone) to record with, but it doesn’t have the option to change the frame rate/shutter speed in video. I’ve been meaning to make a better one, but the last couple of years I was working abroad so didn’t have access to the globe (I do now I’m back working at Leeds Uni), and to be fair I wasn’t expecting it to make the rounds again on blogs/twitter given we made it 3 years ago.
What you can do is up the exposure value (EV) to decrease the shutter speed and put an neutral density (ND) filter to darken it back down so that it doesn’t blow-out to white. Even a sunglasses lens can do the same job as an ND filter.
It’s the same process used to capture those “see of mist” seaside photos and flowing water/waterfall/stream photos.
Pretty slick.
Now they just need to have a setting so the timing matches the video frame rate so their videos do the project justice.
That is really great! Only complaint is the camera video flicker, but it does make it easy to see how accurate the LED timing is.
Hollywood brain-washed HaD authors can only see the death star. That´s some serious macular degeneration. It´s a “carnage”
Resistance is futile. Oh wait, that’s Star Trek. I did mention their using it for showing an Earth overlaid with weather information and the ISS position. I thought that was pretty cool. Made me wonder if somehow a second ring with larger diameter could be spinning outside the first so that the weather info and ISS could really be “over” the Earth.
And X-wings could be swarming over the Death Star.
Or have a second string of LEDs simulate the vent
(Leeds uni student here) It’s been knocking around the university for a few years now; Usually gets wheeled out for taster days etc. It’s a pretty nicely done chunk of kit, though; I liked the way they did the modular LED boards.
If it rotates at 300 RPM, shouldn’t the frame rate only be 5 FPS?
how much radii in one diameter ?
14 LED boards, 7 on each half.
There are two arms, each displaying half of a frame at a time, so the actual frame rate is double the rotation speed.
Video with no audio? That shit must be loud
Something to consider, interlace the LED’s on both halves of the ring that spins and get rid of the evil spaces between them. IMHO it would look a lot better with a smaller presentation but no gaps.
The gaps are an artifact of the frame rate problem that several people have mentioned. To human vision it should look solid, if a little flickery.
Oh these youngins and their calling SNES “Nintendo.”
. My previous favourites are the bike-wheel ones… but this is now the coolest POV implementation I’ve seen.