The ring game is meant to be very frustrating, while also being very easy to learn and attempt. Players must move a ring from one end of a copper pipe to another without touching the pipe with the ring. The game is large and mounted to the wall, so they can stand around it and spectate or share strategies. The tone generated by the ring in the failure mode is annoying and demoralizing. The game is meant to appeal to those with a dexterity oriented skill set who appreciate a challenge.
The microprocessor running the game is keeping score. If the players have successfully touched the start terminal, they get a point. If they successfully touch the end terminal, they get a point. And if they touch the pipe in the middle, their score resets to zero. All terminals are electrically isolated and pulled up to digital high, and the ring is grounded.
The pipe circuit game has logic similar to the board game "Mastermind". Players are presented with a series of copper pipes on the left side of the game and an equal set on the right. Using flexible steel mesh pipe, they can connect one copper pipe to another. Only three "starting" pipes are relevant and they are each mapped to an "ending" pipe. If they involve a starting pipe in a connection, then a light turns on. And if they match the pipes correctly, the light turns green.
Half of the pipes are energized with a filtered voltage between 1 and 5v, and the other half are pulled down to ground through a high impedance resistor (high enough not to throw off the voltage readings, but not so high that human hands can make valid electrical connections). The microprocessor knows which three voltages it is looking for and the matching analog read ports.