A Useless Robot, But Kawaii

The term “kawaii” has more depth in Japanese culture, but in the West we tend to think of it as a synonym for “cute” — just in a Japanese Hello Kitty sort of way. It is a particular kind of cute that is very much a “know it when you see it” type of thing. And this Kawaii Useless Robot built by Tobychui certainly fits the bill.

The classic “useless machine” is a novelty device with only one function, which is turning itself off. The quintessential design was created by Marvin Minsky in the 1950s and looks like a box with a switch on top. When a curious passerby flips that switch to “on,” the machine receives power. That power lets it perform its one function: extending an arm up through a lid to flip the switch back to “off.” The clever engineering and even cleverer satirical nature of the useless machine has made it a mainstay in certain technical circles.

Tobychui’s Kawaii Useless Robot, inspired by a similar project completed by Kairoshim in 2012, does the same thing, but in a much cuter way. In addition to flipping its switch back to “off,” this robot also wiggles and pulls angry faces to make its displeasure clear. The integrity of the useless machine concept remains mostly intact, but with a new personality that is kawaii grumpy.

Unlike the simplest useless machines, which are purely electromechanical devices, this Kawaii Useless Robot functions under the control of a microcontroller. It has an ESP32 microcontroller on a custom PCB inside the box, giving it much more capability. Its two most basic functions are detecting the flip of the switch and actuating a servo to flip that switch back off. But it also handles the additional functions that give this device its personality.

The most important is the LED matrix display that shows the robot’s mad little face. That consists of eight LED matrix modules, each with an 8×8 grid of red LEDs, resulting in a total resolution of 32×16. Those shine through translucent black acrylic, so they aren’t visible when the LEDs are off. The other personality-enhancer is a pair of stepper motors that let the robot move around. They give it the ability to shimmy in outrage or drive backwards to escape the switch-flipper.

Together, those capabilities make this robot much more interactive than a typical useless machine. That does diminish the original joke a bit, but we think the sacrifice is acceptable to achieve such cute results.