Beating the Motion Sensor
A laser beam allows small movements to be tracked by the human eye. Could you beat this motion sensor?Copyright 2004 Sandia National Laboratories http://www.sandia.gov/
Lighting is responsible for nearly one-third of the electricity use in buildings. One of the best ways to conserve energy is to make sure the lights are turned off when no one is in a room. This process can be automated using motion sensors. In this activity, students explore material properties as they relate to motion detection, and use that knowledge to make design judgments about what types of motion detectors to use in specific applications.
Through this activity, students experience how different types of common building and furniture materials interact with motion detection technology, and extend that knowledge into the field of architectural engineering. Architectural engineers are often involved in designing the systems that control building lighting, heating and cooling systems. They also determine what types of sensors are most appropriate for each space type and the amount of use it receives. Students in this activity act as engineers making decisions like those made during commercial building design.
After this activity, students should be able to:
- Describe how the two main types of motion sensors (passive infrared, or PIR, and ultrasonic) detect motion using heat and sound waves.
- Describe how different materials interact with heat and sound waves.
- Explain why a motion sensor did, or did not, "see" a moving object because of the way in which materials interacted with it.