POV LED Staff Takes Art For A Spin

The human body does plenty of cool tricks, but one of the easiest to take advantage of is persistence of vision (POV). Our eyes continue to see light for a fraction of a second after the light goes off, and we can leverage this into fun blinkenlight toys like POV staffs. Sure, you can buy POV staffs and other devices, but they’re pretty expensive and you won’t learn anything that way. Building something yourself is often the more expensive route, but that’s not the case with [shurik179]’s excellent open-source POV staff.

There’s a lot to like about this project, starting with the detailed instructions. It’s based on the ItsyBitsyM4 Express and Adafruit’s Dotstar LED strips. You could use the Bluetooth version, but it’s already quite easy to load images to the staff because it shows up as a USB mass storage device. We like that [shurik179] added an IMU and coded the staff so that the images look consistent no matter how fast the staff is spinning. In the future, [shurik179] might make a Bluetooth version that’s collapsible. That sounds like quite the feat, and we can’t wait to see it in action.

As cool as it is to wave a POV staff around, there’s no real practical application. What’s more practical than a clock?

9 thoughts on “POV LED Staff Takes Art For A Spin

  1. Persistence of vision displays have a long history. I first saw one using LEDs and a computer in the late 1970s at a meeting of the New England Computer Society, a long-gone group that used to meet at MITRE in Bedford MA. One month somebody demonstrated what he called the Magic Wand, a flexible stick with eight LEDs that could be used to display a line of text.

    You used it by holding the wand in one hand and making it wave back and forth. Like the arm of a metronome, the wand had a natural period, so the software could just assume that; it had switches to detect the ends of travel so it could be synchronized properly. It wasn’t a standalone device; it was tethered to a microcomputer board.

    At the time, other methods of displaying an entire line of text were costly. Unfortunately for the inventor, few users were interested in holding a display device to make it wave so it never caught on.

    1. Another often overlooked example is many of the 7-segment LED displays with more than one digit.
      These are often driven one digit at a time and quickly cycling through them, relying on the POV effect.

      It isn’t the most glamorous implementation, but quite a clever one considering the options in the 70’s for driving such displays, often coming down to a handful of 7400 series logic chips and little more.

  2. The very first TV’s used this before cathode ray tube television where invented.
    They read the light with a light dependent resister (LDR) looking through holes in a spinning disc.
    Then to show the image the light level from a lamp was changed while viewing it through holes in a spinning disc.

    When the BBC started the first TV service in the world, they would use the spinning disc one week then the cathode ray tube the next.
    They chose and we ended up using cathode ray tubes.
    This was before World War Two.

  3. “Our eyes continue to see light for a fraction of a second after the light goes off”

    Don’t you mean our eyes continue to perceive the effect of the light after the light goes off?

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