Programming Lego Mindstorms NXT

Chapter 9. Sounds Received and Emitted

Introduction

The NXT brick can receive sound using a sound sensor, and emit sound using its loudspeaker. First we will look at some of the things that we can do with a received sound.

Sound is another way of communicating with a robot from a distance. The microphone in the sound sensor is better at picking up high-pitched signals, such as clapping or whistling, so we will confine ourselves to using this type of signal.

Start and Stop

As an illustration of what can be done with a sound signal, the program in Figure 9.1 makes a mobile robot start running upon hearing a sound, and stop running when it hears a second sound. Sometimes when the robot is running it will hear the sound of its own motors and ...