The parts that come in an EV3 package (Home or Education) can be broadly classified into four categories: brick, motors, sensors, and Technic pieces.
The brick is both the power source and the control center of the robot. All of the motors and sensors are attached directly to the brick and are controlled by it. The brick is described in greater detail in the An overview of the brick section of this chapter and is illustrated in the following image:
EV3 comes with one medium and two large (high-torque and high-precision) motors. The motors can be operated in two modes: they can be run at a constant speed or rotated through a fixed angle. In both modes, the motors can be queried for their current angular position, which enables motors to function as both input and output devices. Motors are described in greater detail in Chapter 2, Sensors and Motors. In the following figure, the large motor is on the left and the medium motor is on the right:
EV3 comes with a variety of sensors that provide the robot with information about its environment. The sensors that are common to the Home and Education sets are:
- Touch sensor
- Infrared sensor
- Color sensor
The Education set additionally comes with ultrasonic and gyroscopic sensors. These sensors are described in detail in Chapter 2, Sensors and Motors.
Technic is a Lego series primarily consisting of slotted beams and pins designed for 3D construction with particular emphasis on allowing rotation. Technic pieces are the most numerous component of the EV3 package and bear primary responsibility for the actual construction of a robot.
Along with a variety of slotted beams and pins, the EV3 package contains axles, gears, crossbars, wheels, tracks, and a number of decorative pieces among others, as shown in the following image:
The EV3 brick has been designed with slots built into three of its sides (the bottom, left, and right faces), which allow it to be attached directly to other Technic pieces and thus incorporated into the body of the robot.
The construction of a robot consists of situating the brick, using Technic pieces to build the body around it, and then attaching motors and sensors at strategic locations. It brings back the sheer childhood joy of playing with Lego.