Impractical electromechanical display
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Gavan Fantom 5e72f0a55d Pixel hardware and software 7 years ago
STL Pixel hardware and software 7 years ago
scad Pixel hardware and software 7 years ago
software Pixel hardware and software 7 years ago
README Pixel hardware and software 7 years ago


To make the pixel, 3D print all 7 parts.

The pixel insert (screw) should be in one colour. The case and guide should
be in a contrasting colour. The small parts can be in any colour, and are
only visible from the back.

Print one pixel before trying to scale up. Some of these objects are difficult
to print and will require a well set up 3D printer.

I printed the large parts on an Original Prusa i3 MK2S and the small parts
on a Creality CR-10. The printing time was of the order of two weeks plus
failures and spares.

There is some redesigning that would be helpful before scaling up.

The pixel also requires 2 nails and a Tower Pro SG90 servo motor.

Driving the system requires a Pololu Mini Maestro 24-channel USB Servo
Controller for each 24 servos.

Also required is a suitable 5 volt power supply. I used a Mean Well RS-150-5
for each servo controller. The worst case current of the servo is around an
amp, and while the average current will never reach anywhere near that, I sized
the power supplies accordingly so that they should never shut down due to
transients. The PCB trace on the servo controller is unlikely to be able to
handle that much current for long.

Note that the pixel grid will need external mechanical support. I used parts
from a couple of monitor stands, but any sturdy vertical pole on either side
should suffice. Black cable ties will then hold it steady.

Assembly should be done carefully. Most parts are push-fit, but that does
rely on 3D printing tolerances. You may need to slightly adapt some of the
sizes in the source files to your printer, or be careful about how much
you file or cut away the rim of the first layer.

Prototyping with a single pixel is essential.