Pop-Up Clock and Flipper Clock – Magnetic Digit Elements

Season’s Greetings


It’s been a while since my last post, while I have been working on two new proof-of-concepts for some new clock displays. Both of these displays employ magnetic coupling – attraction and repulsion – to animate elements (segments / flippers) of a numeric display that will be incorporated into a clock.

The first is a single 7-segment digit for a new POP-UP CLOCK.

Pop-UP Clock: Single 7-segment Digit

And the second, for The FLIPPING TIME CLOCK -is a 3×3 flipper array for a digit that displays numbers 0-9 as “pips” on a domino.

Flipper Clock Digit: Showing 3×3 array of flippers used to display the numbers 0-9 like pips on a domino

Interested in reading how these elements work????

The genesis of the ideas…

First of all, both of these designs came from some thinking after a conversation with two friends – Mike Krause and Doug Commons – while we were discussing magnetism and its detection, and a specific application that Mike was working on for a client. It got me thinking that with the ubiquity and low cost of rare-earth magnets, I could use the fundamental properties of attraction and repulsion to articulate display elements that would inevitably end up in a clock.And they both have and I plan to continue to scale them to complete time devices.

Secondly, I believe that both of these designs are completely original and unique so hopefully all of the experimentation – which involved many (many) variants that did not work – was not in vain. To me, engineering is a verb, and it is in the act of the design and development of something novel that I get my kicks.

Thirdly, I am fortunate to count as friends a group of extremely smart engineering ‘geeks’ who, like me, enjoy a challenge… Nothing occurs in a vacuum and some of their musings, comments and suggestions during our “Geek Meets” ultimately find their way into my designs. In addition, as an engineer, I have the pleasure of their comradery and, I guess, enjoy in their validation.

So here’s how they work…

POP-UP CLOCK DIGIT

In the video below, the digit segments are articulated to display the four digits of the current time (19-29).

The assembly consists of a front face, with the 7-segment cut-outs, and a rear plate that mounts 7 separate servo motors. Each segment is made up of two separate parts. The first part – made from 6mm HDPE – attaches to a small metal geared servo (and is often referred to as a servo ‘horn’) and has arms that hold a pair of 5mm rare-earth element magnets. The second part, cut of two pieces of 6mm HDPE, also sandwiches a pair of magnets. This upper part is constrained to move in and out of the cut-outs of the face plate, and “floats” above the servo horn.

Pop-Up Clock Digit: side view showing the servos mounted on the rear plate and the segment elements located behind the cut-outs of the front face

The servo is controlled to rotate between two stable positions 180 degrees apart. In one position, the magnets of the servo horn align and attract the magnets of the upper segment, pulling the segment below the plane of the front panel. In the other position, the servo horn magnets counter and repel the magnets of the upper segment, forcing the segment to pop-up above the surface.  In this way, each segment can be controlled to show the numbers 0 to 9, and also a ‘-‘

FLIPPER DIGIT

In the following video, each flipper of a 3×3 matrix is flipped between its two stable positions – red and white.

 

The assembly consists of a 3×3 matrix of flipper mechanisms, mounted on a rear plate. Each flipper mechanism is made up of two separate parts. The first part – made from 6mm HDPE – attaches to a small plastic geared servo (a servo ‘horn’) and has arms that hold a pair of 5mm rare-earth element magnets. The servo rotates the horn in a horizontal plane. The second part, the flipper, is cut from 6mm HDPE and holds a single magnet. The flipper, mounted above the servo horn upper part, is allowed to rotate 180 degrees to display either a red, or white face.

Flipper Mechanism: showing set-screw to hold the rod that acts as pivots for each flipper

Flipper Mechanism: showing servo mount below each flipper

Flipper Mechanism: showing cables to each servo running underneath flippers

In operation, the servo is controlled to rotate the horn between two stable positions 180 degrees apart. In each case, the flipper is magnetically attracted to the closest pole of the servo horn and stays in position. As the servo horn is rotated, the magnet on the other end of the servo horn repels the magnet of the flipper which starts its flipping rotation. As soon as the flipper has moved past its vertical, its magnet is then attracted to the magnet of the other end of the servo horn, to complete its rotation. The ‘flipped’ flipper then stays in that stable position until the servo horn is rotated again.

Freaking attractive, huh?

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