the motion-sensing radar
In this chapter, you’ll learn how to add your own sensors to MINDSTORMS EV3 by creating a radar device that can sense motion, as shown in Figure 7-1.
This radar uses the Doppler effect, by which objects in motion shift the frequency of a radio wave. If an object such as a human, vehicle, or animal moves through the radar beam, the radar detects its presence.
The Motion-Sensing Radar has two advantages over the standard LEGO-based sensors. First, the radar can see through windows, walls, or doors. So, for example, you can keep the Motion-Sensing Radar indoors with a view through a window to detect whether someone or something is moving outside. Or you could learn whether someone is approaching a closed door. Second, ...