Now that the system can both hear and speak, you'll want to provide the robot with the ability to respond to your speech and execute commands based on the speech input. Next, you're going to configure the system to respond to simple commands.

In order to respond, we're going to edit the continuous.c code in the /home/pi/src/programs directory. We could create our own C file but this file is already set up in the make system and is an excellent starting point. You can save a copy of the current file as continuous.c.old so that you can always go back to the starting program if required. Then, you need to edit the continuous.c file. It is very long and a bit complicated. However, you are looking for a specific section in the code, which is shown in the following screenshot. Look for the /* Exit if the first word spoken was GOODBYE */ comment line:

In this section of the code, the word has already been decoded and is held in the hyp variable. You can...