Chapter 2, Setting Up Your Robot

1. Sensors mentioned in the text include:
   • Sonar sensors
   • Cameras
   • Microphones
   • Buttons
   • Analog-to-digital voltage sensors
   • Temperature via thermistors
2. PWM stands for Pulse Width Modulation, a type of digital-to-analog control scheme where pulses are sent out that get longer based on the amount of control desired. It is commonly used to control DC motors.
3. As the name says, analog to digital conversion (A2D) takes in an analog value, typically a voltage, and converts it into a digital value or number that the digital part of the computer can understand.
4. As stated in the text, the subsumption architecture was originally described by Dr. Rodney Brooks, a professor at MIT who would later help found iRobot Corporation and invent the Baxter Robot. Rodney was trying to develop analogues of insect brains in order to understand how to program intelligent robots. Brooks, Rodney. Cambrian Intelligence: The Early History of the New AI. MIT Press, 1999. Boston, MA.

5. The three laws of robots from Isaac Asimov first of all are fictional, while the subsumption architecture is a real process that is used to make real robots.

The three laws are:

• Robots will not harm a human being, or through inaction, allow a human to come to harm.
• Robots will obey orders from humans except when that violates the first law.
• Robots will protect themselves from harm, except when that violates the first two laws.

The bottom layer of the SA (subsumption architecture) is the part that looks inside the robot and takes care of internal systems. I like to compare it to the autonomic nervous system. That protects the robot. The second layer is the short-term manager. It tells the robot where to go, which includes obeying orders from users. The top layer contains the strategic thinking and planning processes. The correlation is pretty weak, to be truthful.

And, yes, readers, I am aware of the fourth, or Zeroth, law:  the robot shall not harm humanity , or allow humanity to come to harm.  That was a later addition.

6. This is a personal, subjective question for the reader. Why do we give robots names and not washing machines?
7. The most important variable in this set is the ROS_MASTER_URI, which tells all of the ROS parts where ROSCORE is located at. ROSCORE makes all of the connections in a ROS system.