Persistence of vision (or POV) is the phenomenon by which the eye, seeing a rapidly moving objects, stitches together the object’s position at different times into a single cohesive image. This phenomenon is leveraged by CRT displays, which use raster scanning to draw individual pixels in each horizontal scanline before returning to the beginning of the next one. In contrast, our spherical display displays scanlines vertically. We have built a spherical display that creates a picture by rapidly alternating the colors displayed by each of a column of LED pixels. Each column of vertical pixels displays simultaneously. The physical location of the light source is then moved by a short distance before the subsequent vertical scanline is displayed.
Our system consisted of a 60-pixel LED strip mounted on an acrylic ring, which was lined with a 60-pixel LED strip running an array of LED pixels. Its bottom is mounted to a 6V DC motor with an encoder which uses a Hall-effect sensor to accurately determine its position. The motor’s rotational velocity is set to 500 rpm. A 6-wire slip ring from Adafruit allowed us to connect the LED power, clock, and data lines from a stationary frame to the rotating acrylic ring. (Since 6 wires are available, 2 wires each are used for power and ground lines.)
Each Monday is ArduinoMonday here at Adafruit! Be sure to check out our posts, tutorials and new Arduino related products. Adafruit manufactures the Arduino right here in the United States in cooperation with arduino.cc. We have a huge selection of Arduino accessories and all the code and tutorials to get you up and running in no time!
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.