Tag Archives: servo motor multiplexer

PUSH-UPs… 2×8 pixel unit

After the design and build of the prototype PUSH-UPs articulated display panel, I have now built the first of 4 identical modules, each containing 16 controllable rods.

The four modules will form an 8×8 “pixel” animated surface display system to create a dynamically changing topography.

Stimulus for this display unit will be derived from a camera, an arrays of sensors, or purely from software that simulates different surface topologies.

PushUps: Top view of the 2×8 design

The design of the 2×8 unit parallels that of the 2×4 prototype. However, I changed the design of the servo horn and connecting linkage to ensure that the “pixels” fall onto a 33.34mm pitch (2 times the 16.67mm pitch of the LEDs on a 60 led/metre strip) for both rows and columns.

PushUps: side view showing the thinner servo horn and offset connecting linkage

In addition, the underside of the top plate was cut to allow for a simpler installation of the LED strip, that now contains a total of 34 LEDs.

PushUps: showing LED illumination for each “pixel” element

PushUps: all 16 units pictured in mid-articulation of a sine wave

PushUps: closeup of the servos

PushUps: closeup of the nano, 16-channel PWM/servo multiplexer and buck power supply

PushUps: close-up of the underside of the top plate showing installation of LED strip


Getting there!

PUSH-UPs: an articulated display panel

Introducing PUSH-UPs, an articulated display panel.

PushUps: a prototype for an articulated display surface

This is a 8 “pixel” prototype of a animated surface display system. The final goal is to create a surface with a hundred or more separately articulated “pixels” to create a dynamically changing topography. Stimulus for the larger unit may be from a camera, an arrays of sensors, or purely from software that simulated different surface topologies.

I’ve been talking about designing an articulated tabletop for sometime now – taking my inspiration from TRANSFORM, from the Tangible Media Group at MIT Media Labs. While I am not trying to copy their design, the key to this idea is in the design of a moving “pixel” that is small, provides several inches of “travel”, is able to be illuminated and, most importantly, cheap! This allows the design to be scaled to whatever size is desired. As this “pixel” element is actually a linear actuator, I have considered and experimented making all sorts of actuator designs but nothing I came up with is satisfying these criteria. In the video we can see that the table-top part of each pixel is a small square-section plastic tube connected to a wire or plastic linkage that connects to the control box below. But what is this control element and how does it provide the 4″ of travel that the video shows?

In a telephone discussion with Doug, an engineering colleague of mine, we noodled through some simple design ideas that would use cheap and readily available servo motors to articulate acrylic rods that can pass light.

So, the seeds of this prototype design were sown.

So, voila. PUSH-UPs.

I have made many designs using servos (see PopUp Clock, and Flipper) and I had plenty of the small metal-geared MG-90s on hand. In addition, I have created lots of clocks recently (yet to be posted) that use acrylic rods as light pipes for colourful displays so I had lots of 1/4″ and 3/8″ rod stock. And of course, I always have yards of addressable LEDs.

PushUps: going through the motions. Picture captured the unit articulating a sine wave

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