Ultrasonic Sensor Robot Design Project: Don't Bump into Me!
A LEGO robot with an ultrasonic sensor is used in this activity. Similar sensor concepts are used in sonar technologies that survey the ocean floor.Copyright (middle) 2009 Bermuda: Search for Deep Water Cave via NOAA; (middle) NOAA; (left) 2006, Flickr: Robot 1 via Nogwater, Wikimedia Commons http://oceanexplorer.noaa.gov/explorations/09bermuda/background/multibeam/media/multibeam_fig2.html
http://oceanservice.noaa.gov/gallery/image.php?siteName=nosimages&cat=Multibeam%20Sonar
http://commons.wikimedia.org/wiki/File:Robot_1.jpg
Students' understanding of how robotic ultrasonic sensors work is reinforced in a design challenge involving LEGO® MINDSTORMS® EV3 robots and ultrasonic sensors. Student groups program their robots to move freely without bumping into obstacles (toy LEGO people). They practice and learn programming skills and logic design in parallel. They see how robots take input from ultrasonic sensors and use it to make decisions to move, resulting in behavior similar to the human sense of sight but through the use of sound sensors, more like echolocation. Students design-test-redesign-retest to achieve successful programs. A PowerPoint® presentation and pre/post quizzes are provided.
Ultrasonic sensors send out sound waves and measure how long it takes reflected waves to come back—similar to how bats echolocate. Knowing the velocity of sound and the time it takes to travel forward to the object and come back enables estimation of the distance of objects from the sensor. Engineers have incorporated the same concept into many engineering designs. For instance, radars are used to monitor weather and storms, measure speeding vehicles, navigate airplanes, and measure the changing amounts of ice in Polar Regions. Sonar technologies enable naval navigation, deep sea fishing, and surveying the ocean floor. Ultrasound equipment provides a medical diagnostic tool.
Computer programming is key to many modern engineering designs. As students design robot programs using the engineering design process in this activity, they begin with a "goal" or "concept" of what the program solution needs to do, before they begin writing the code. Next, the process of working on the code and "debugging" it inherently constitutes "revising and improving their designs based on the results of testing." In that sense, the thought processes required to code programs that meet problem constraints are very similar, if not identical, to the thought processes required for traditional engineering design of physical structures and products.
After this activity, students should be able to:
- Program a LEGO robot to take input from ultrasonic sensors and make decisions such as moving around and avoiding obstacles.
- Explain how the program and the ultrasonic sensors work.
- Relate the program (robotic response to ultrasonic sensor information) and how the ultrasonic sensor works to human and bat methods for estimating distance.