A useless machine is described on Wikipedia as a device which “has a function but no direct purpose.” We most often see these in the form of the classic “useless box,” which has an external on/off switch. When you flip the switch to “on,” an arm pokes out of a compartment in the box and flips the switch back to “off.” You can apply some sort of philosophical meaning to that if you like, but it is really more of a joke for engineers than anything else. In the same vein is The Conflicted Candle built by James Cochrane, which can’t decide if it wants to be lit or not.
Useless machines date back at least to the work of Bruno Munari in the 1930s, which was meant to make a statement about our technological fervor by being largely pointless. Many implementations of useless machines have been built over the years, and the one thing they all have in common is that they were engineered to do something nonsensical. This is, however, the first useless machine we’ve seen that features a candle. The Conflicted Candle doesn’t do anything except continuously light its own wick and then immediately snuff out the flame.
The Conflicted Candle is controlled by an Arduino Nano board, which spins a gear motor via an L298N motor driver. All it does is endlessly rotate that motor. The motor, in turn, spins a big 3D-printed gear alternately clockwise and counterclockwise. Two 3D-printed linkages are mounted in such a way that they move past the candle. The end of one linkage contains an electric igniter and the end of the other contains a snuffer on an arm actuated by a servo. When the first linkage passes by the candle it lights the wick, and when the second linkage passes by it snuffs the flame. It then repeats that process over and over again as if it is unable to decide if it wants to let the flame continue to live or not.