This is our Arduino radar finished. It uses an Arduino Uno, ultrasonic sensor, servo motors, and jumper wires.

The radar program is run from Processing 3.  The radar works by sending out high-frequency sound pulses from the transmitter side of the sensor. The pulses then reflect off a physical object and back to the receiver side of the sensor. While this is happening, the Arduino tells the servo motor to move small in increments from 0-180 degrees and back. The Processing 3 program then converts the data received by the Arduino into a radar on the computer screen.

http://education.rec.ri.cmu.edu/content/electronics/boe/ultrasonic_sensor/1.html

This relates to engineering because we are using technology to build machines to solve problems. For example, you could use this radar to find out if someone is in front of your bedroom door.