Split Flap Display

The split flap display was a very widely used technology in the 80s and 90s at train stations, bus stations, and airports, to display the schedule and timetables. They are extremely clear to read from a long distance, and the characters can be very large. On the down side, it relied on electromechanical technology which required maintenance, and dust free environments.

It took longer to change the display because the wheel could move in only one direction. Therefore changing a character meant moving the wheel to the reset home position first, then moving the flaps forward one at a time to reach the desired character. Most people will remember the familiar flicking through a book sound these displays made.

A metal strip, for each display wheel, prevents the front card from flipping over. As the wheel turns the front card lowers vertically and the metal strip can no longer hold it back, therefore it flips over by gravity.

Here is a view from the top showing the stack of flip cards.

The flip cards are around the outer circumference edge of the wheel. Each card has a pivot hole allowing it to move.

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