Useless Box Project

The Italian artist Bruno Munari began building "useless machines" (macchine inutili) in the 1930s. He was a "third generation" Futurist and did not share the first generation's boundless enthusiasm for technology, but sought to counter the threats of a world under machine rule by building machines that were artistic and unproductive.[1]

Components

Limiter Switch

Battery Pack

Switch

Motor

Limiter Arm

Switch Arm

SOLIDWORKS Design

The base of the box.

Added structures to support the motor and limiter switch.

The hole for the heat-set nut, there is one on each side.

The complete design for the interior of the Useless Box. (without components)

The outer frame for the box, matches the shape and dimensions of the interior.

The heat-set holes on the outside line up with those on the inside.

This is the design I settled on for the lid after many failed test prints.

Motion GIFs

The lid of the box moves open when the lever comes out.

The motor moves the arm out to hit the switch, and reverses once done.

Test Prints

The first test print of the lid was too thin. It snapped across the top of the lid as well as the part connecting it to the base of the box.

For the second test print, I made both the lid and the support thicker. Although the lid was sturdy, the support connecting it to the base still snapped off.

For the third test print, I switched from Rapid PETG to PLA filament, which is less flexible. The same part still snapped as it was not thick enough. There was also not enough space between the pin and the lid for it to move smoothly.

I doubled the thickness of the pin for the fourth test print, as well as leaving a 2 millimeter gap between the pin and the lid. The print failed towards the end because there were no supports inside the gap. The dimensions were correct at this point.

Test print five was a success. I printed the same model as #4 however I added supports to the inside of the lid. This made sure that it would print correctly, although I had to spend time digging the supports out.

I test-printed the arms to make sure they would fit on the motor, which they both do. However, because these are detachable, they can be swapped out if necessary.

I also test-printed a section of the top of the box for the lever. I did this before realizing that the lever had a circular screw that is used to attach it, so this whole part ended up being useless.

Soldering (to be added)