Activator
From Sega Retro
The Sega Activator was an octagonal game controller for the Sega Mega Drive/Genesis that used infrared beams to interpret movements. The Activator was placed on the floor, and the player stood inside the octagon, punching and kicking to break the light beams and send signals to the Genesis. It was marketed as a new type of martial arts simulator. The light beams were also easily distorted by a non-flat ceiling, or obstructions, such as beams of a ceiling fan or light fixture. It did not see much commercial success. Few games were designed to be used with it, one of them being Eternal Champions. Additionally, some normal games, most notably Mortal Kombat and Comix Zone, are actually more difficult to play with an Activator.
The Sega Activator was based on a musical instrument called the Light Harp conceived by musician and martial artist Asaf Gurner. It was brought to market by Interactive Light under a licensing agreement with Sega.