What lies beneath these
Pinball machines have evolved into complex, computer-controlled mechanical games over the decades, but the layout has nearly always consisted of an inclined playfi eld and a backbox – the machine’s brain. To score points, players aim for targets, bumpers and slingshots. When a ball hits one of these, two contacts are forced together in an electro-mechanical switch, completing a circuit and registering a strike. Every switch is wired to a unique reference point within a switch matrix. A microprocessor locates a strike by detecting the change in electrical current at a particular grid reference point. It then processes the instruction dictated by the software stored in an EPROM chip (to increase the score for example). Most of the moving elements, like the fl ippers, are controlled by solenoids. Solenoids are electromagnetic tubes that, when powered, attract metal actuators towards them. This attraction can be manipulated into quick movements by rapidly switching the power on or off to certain solenoids – handy for kicking balls away from bumpers. Tilt sensors detect deliberate tilting and excessive shaking while a weighted metal rod swings like a pendulum within a conductive ring, this means that over-enthusiastic players will cause the rod to swing and make contact with the ring, activating a warning.