1. The Sentinel Designed by Aleksandras Kaknevicius Intelligent Machine Design Lab Fall 2011 TAs: Ryan Stevens & Tim Martin Dr. Eric M. Schwartz & Dr. A. Antonio Arroyo

2. Basic Description The Sentinel should be able to successfully safeguard a doorway or hallway, blocking intruders or alerting others when an intruder has tried to pass it. If the passerby is friendly, he/she will be able to produce a pattern of four audible frequencies and the robot will allow passage.

3. Sensor List  Microphone with Preamplifier x1  Pyroelectric Sensors x 2  Sonar Rangefinders  Maxbotix LV-MaxSonar-EZ0 x 2  Maxbotix LV-MaxSonar-EZ4 x 1  Bump Switches x 2

4. Sensor List  Microphone with Preamplifier x1  Pyroelectric Sensors x 2  Sonar Rangefinders  Maxbotix LV-MaxSonar-EZ0 x 2  Maxbotix LV-MaxSonar-EZ4 x 1  Bump Switches x 2

5. Microphone Preamp Design

6. Frequency Detection

8. Initial Detection & Tracking Two Pyroelectric Sensors Rangefinder Sensor Tracks and stays in front of approaching target.

9. Revised Detection & Tracking

11. Obstacle Avoidance  Sonar Rangefinders  Maxbotix LV-MaxSonar-EZ0 x 2  Based on distance difference between the two sensors. If both sensors read a close distance, an obstacle is directly ahead, and the robot needs to turn fast to avoid it. If the one sensor reads a close distance, and the other reads a far distance, then a lesser turn is required.

12. Final Product