Buzzer (or Beeper)

An audio device used to signal an event, the way we look at them, they are basically used in the same way as LED's but instead of giving us a light output they give us an audio output. Which of course is more irritating and should be used to alarm users of improper use of the robot, or of incoming danger. They are a piezoelectric devices which means that there is an elastic disc inside the buzzer, this disc vibrates when we output current to it, this vibration is the sound that we hear.