Building a Mechanical Flip-Dot Style Display Using a Bunch of Servos

Electromechanical flip-dot displays used to be very common in places like train terminals, because they could show dynamic information in large, high-visibility characters. But then modern display technologies, such as LCD screens, became practical and affordable enough to make flip-dot displays obsolete. Today, flip-dot displays are very expensive and hard to come by, and that is a shame because they're still really cool. To provide a more affordable and versatile alternative, AIRPOCKET designed this mechanical display actuated by a whole bunch of servo motors.

Traditional flip-dot displays operate using electromagnets, so pulsing the electromagnet with a particular polarity will flip the dot to the corresponding state. In the past, when the necessary components were manufactured in large quantities, flip-dot displays were relatively affordable and practical. But building a flip-dot display today costs a lot of money. Micro servo motors for hobbyists, on the other hand, are very inexpensive and easy to drive. When purchasing in bulk, it is possible to get them for less than $1 per piece. AIRPOCKET determined that it was more practical to use servo motors to actuate their display than traditional electromagnets, and that provided an additional benefit.

The "pixels" on a flip-dot display can only be set to one of two states. Most often, one side is black and the other side is a bright color. But because AIRPOCKET's mechanical display uses servos, the "pixels" can be set to any angle. That enables some interesting possibilities. Depending on the shape and color of the pixels, along with the lighting conditions, this display can create more variation than just "on" or "off."

All of the pixel flaps on the prototype 8x8 grid were 3D-printed, as were the actuation mechanisms. The servo motors all seem to be standard 9g models, which are popular among hobbyists. AIRPOCKET doesn't provide details on the other hardware, but we can assume that they're using some kind of microcontroller to control the servos through multiplexing.

This is still a work in progress, but AIRPOCKET's concept is a great alternative to expensive flip-dot displays and we're excited to see where the project goes.