MOBILE ROBOT WITH INFRARED DETECTION

1. MOBILE ROBOT WITH INFRARED DETECTION Sean Coenen http://www.snc.edu/compsci/cs460/coenst

2. General Requirements: • The robot uses infrared detection to compute distances. • The robot must be able to react to its environment using two input detectors using a priority based scheduling algorithm. • The robot must stay out of harms way • Design and implement at least two personalities

3. The Brains • HandyBoard • Microcontroller • 32K of battery-backed static RAM • Outputs for four DC motors • Input for a variety of both Analog and Digital Sensors • Runs InteractiveC Example

4. Input Sensors • Bump Sensors • Digital Inputs • 1 = Sensor Hit • 0 = No Hit • Four located on robot chassis

5. Input Sensors • GP2D02 Sensors • Digital Input Sensor • Only returns value at specified interval • Returns value based on distance from object

6. Input Sensors • GP2D02 Sensors • Takes distance reading when enabled • Reports the distance as a byte-value • Returns meaningful distances from 10cm (~4") to 80cm (~30") Example

7. Actions: • Avoid Objects • Follow Wall • Follow Object

8. Avoid Objects • Drives straight until confronts object • Turns based on which flags are triggered • Continues straight until confronts another object • Bump Sensors used in case infrared detector misses object Example 1 Example 2

9. Follow Wall • Initially finds wall to follow • Maintains specified distance from wall • Adjusts wheel speed to compensate for distances • Turns to follow corners/turns in wall Example 1 Example 2 Example 3 Example 4

10. Follow Object • Finds object in sensor • Turns to follow object with front sensor • Continues to follow object until robot gets too close or object disappears from field of vision Example 1 Example 2 Example 3 Example 4

11. Solution • Constant monitoring of four infrared sensors • Based on distances from objects, different sensors are triggered • Depending on distances/what flags are triggered, different actions are taken • Avoid Objects – when close, turn away • Follow Wall • When get far away, turn toward • When lose wall, turn to find again • When find corner with two sensors, turn to avoid • Follow Object: • Keep within given distance of object • If lose object, and it appears in another sensor, turn to follow

12. What I Did Not Solve • Make the robot respond/move toward other IR devices • Remote Control • IR Beacons • Interact with other devices with IR detectors • Two robots move around room, but avoid one another

13. Methodology • Start small • Get basic functions working • Distance measurement • Flag variables • Expand to more complicated functions once these concepts are working

14. Strategies • Independent learning about: • Electronics • Wiring/Soldering • Circuits & Resistors • Robotic Explorations: A Hands-on Introduction to Engineering • Book by Fred G. Martin • Professor of Computer Science at University of Massachusetts Lowell • Inventor of Handyboard Microprocessor

15. Techniques • Preemption • Priority • Threads • Global Variables/Flags • Event Programming • Computer Engineering • Processor Chip • Wiring • Circuitry

16. Extensions • Interaction of multiple robots using infrared • Use of more than four infrared detectors for better accuracy/coverage • Explore use of different detection such as Sonar

17. Advice • Mechanical problems can be very frustrating – need patience • Start with small modules and work your way to the large ones • Set a timeline and stick with it

18. Questions? Thank You For Coming!