Keyboards are the most common trigger devices, but MIDI events can also be triggered by other devices. The MIDI guitar is played very much like an electric guitar. Some triggers are activated by hitting them with drumsticks, for example Octapads. Another common trigger is the wind synthesizer, which is played much like a reed instrument. Information stored in a computer can also act as a triggering device. There are a variety of triggers already available, and more in the wings.
