It was christened “Magic Wand” by the sub editor of the magazine. Nowadays this sort of thing is referred to as a POV or persistence of vision project.
Nevertheless it is simple to make and fun so I though it was a good candidate to adapt for the Pi.
Incidentally, not only did I make the cover photo that month, but also the Fractal graphics article was mine as well.
The concept is simple, a column of LEDs flash out a message displaying one column at a time in a rapid sequence. You then move the LEDs so that each column lights up in a slightly different physical location. Then the persistence of vision that the eye possesses makes it look like there are LEDs in each position where they were like up. In other words waggle some LEDs on a stick and see words appear in mid air.
The concept can take many forms, perhaps the most impressive is where the whole unit is spun on a bicycle wheel but here I just want to show how to make the simplest version and let you explore the many possibilities of this effect.
My original circuit had 5mm LEDs arranged in a column, now you can get the LEDs closer together and get a more solid looking display if you use surface mounting LEDs. These come in many sizes but an 0806 or 0605 package will fit nicely on adjacent tracks of veroboard. As well as being many different colours to choose from there are also many different styles. I chose an LED with a diffuser built in to spread the light over the whole area of the package, and not just have a point source. I thought this might be better for photography. However, I don’t think you can go wrong with what ever sort you choose.
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
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.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.