1. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Sentry System Integration and Action See Teacher Guide for printing instructions

2. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Opening Activity What do you do when faced with the following situations? Suspicious person in the hallway at school Smell of gas in your home Lights go out in your classroom Students fighting in the locker room Broken bottles found on the playground

3. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Opening Activity What do you do when faced with dangerous situations? In some cases where the danger is immediate, you should take steps to ensure your own safety first In all cases, the proper response includes alerting a responsible authority figure as soon as possible

4. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Reaction Action How should your robot react to situations it detects? What is your robot’s role and place in the security plan? –This is up to your group to determine –Consider the limitations of your robot What you can detect What you can actually tell based on what you detect Physical limitations Legal liability – even human security guards have very strict limits on their legal authority! What are your robot’s priorities for keeping itself safe?

5. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Investigation Path (b) This version of Investigation 3 continues where the Two-Way Communication Sentry System Investigation left off Groups that chose a One-Way system should use Investigation 3a instead

6. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Logistics The two cooperating groups will continue to work together for this project The two sentries must perform their own lookout duties, as well as communicate with each other Two of a… Kind Of The two sentries must watch their own posts, but also listen for alerts from the other unit

7. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Integration and Action: Technical Review The Sensors

8. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Touch Sensor Poke, Poke? The cross axle probe inserted into the end of the Touch Sensor contact increases its effective range Detects physical contact Tells you: –1 if touched –0 if not touched

9. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Sound Sensor Detects Sound Tells you: –Amplitude (volume) of sound –Low numbers = quiet –High numbers = loud –Can be confused by sounds of different frequencies (pitch) Listen Carefully The Sound Sensor can detect many sounds, from gentle vibrations to jarring collisions

10. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Light Sensor Detects light intensity Tells you: –The intensity of light detected –Low numbers = dark –High numbers = light Light on the front can be turned on or off Light the Way The light sensor in Reflected Light mode shines its own light out and measures the amount that bounces back

11. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Ultrasonic Sensor Detects distance Tells you: –Distance to a surface or object in front –Indicates a distance in cm or inches Ro-Bat The Ultrasonic Sensor uses the same basic principle for detecting distance as cave-dwelling bats do.

12. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Rotation Sensor Rotato Chips The Rotation Sensor is built into the Interactive Servo Motors * If you also know the initial position and how the piece is attached, you can calculate this Detects rotation of the motor axle Tells you: –Amount the axle has rotated in degrees or full rotations –Rotational position of an attached piece* –Linear position of an attached piece*

13. © 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Detection is not enough. Your robot must also be programmed to respond appropriately to anything it detects. Furthermore, it must respond to anything the other robot detects! This investigation is a continuation of the (b) path for two sentries; you will need your previous Investigation 2b program for this Summary See previous investigations or the Advanced > Bluetooth section for Bluetooth information The two sentries should work together as partners, in a sensible way!