Quotes from Mordechai Ben-Ari

Ground sensors are mounted on the bottom of the robot. Since these sensors are very close to the ground, there is no meaning to distance or angle; instead, the sensor measures the brightness of the light reflected from the ground in arbitrary values between 0 (totally dark) and 100 (totally light).

The robot is equipped with an embedded computer (Fig. 1.12). The precise specification of the computer is not important but we do assume certain capabilities. The computer can read the values of the sensors and set the power of the motors. There is a way of displaying information on a small screen or using colored lights. Signals and data can be input to the computer using buttons, a keypad or a remote control.

The computer includes a timer which functions like a stopwatch on a smartphone. A timer is a variable that is set to a period of time, for example, 0.5 s, which is represented as an integer number milliseconds or microseconds (0.5 s is 500 ms). The hardware clock of the computer causes an interrupt at fixed intervals and the operating system decrements the value of the timer. When its value goes to zero, we say that the timer has expired; an interrupt occurs.

We do not give programs in any specific programming language; instead, algorithms are presented in pseudocode, a structured format using a combination of natural language, mathematics and programming structures. Algorithm 1.1 is a simple algorithm for integer multiplication using repeated addition.

Whenever a physical quantity is measured, the measurement can be characterized by its range, resolution, precision and accuracy, concepts that are often confused.

In robotics, accuracy is not as important as precision, because a sensor measurement does not directly return a physical quantity.

Sensors are classified as proprioceptive or exteroceptive , and exteroceptive sensors are further classified as active or passive

Electrical motors used in mobile robots are controlled by modifying the voltage applied to the motors using a technique called pulse width modulation. In many educational robots, control algorithms such as those described in Chap. 6, are used to ensure that the motors rotate at a specified target speed.