“Lightshow created from a cylinder of 288 RGB LEDs
The inspiration for this project is the numerous curves that are created by the intersection of a cylinder and a plane! I wanted to create an LED light show, but I have already built several LEDs cubes recently. I wanted to do something different, both from a hardware and software standpoint. And I thought this would be a fun environment in which to program –something with as much potential as a cube, but which is distinctly different!
I’ve chosen to use 8mm APA106 programmable LEDs for this tower. There’re more expensive than regular RGB LEDs, but they are so much easier to work with both from a hardware and software standpoint. No shift registers - everything is controlled by two data lines. And no ISR (interrupt service routine) and no multiplexing between layers of LEDs - these LEDs are on all the time.
I decided to build my cylinder/tower as a set of 12 rings stacked on top of each other. The rings are 8” in diameter, and each ring contains 24 LEDs spaced 1 ” apart (actually π * 8 / 24 but close to an inch). The rings are themselves separated by 1 inch, so LEDs are 1” apart in both directions. Acrylic rod is used to fasten the rings together to form the tower.
APA106 LEDs can draw 60 ma at max brightness and white, so worst case, this tower could draw 17 amps! But these LEDs are so bright that I seldom have the brightness set at more than 10% in software. And turning the whole tower white isn’t really done anywhere either. So in practice, I never had any problem using the USB port to power it. And if you want to use a separate power supply, 2 amps seems to work fine.”