1. Team Spot Cooperative Light Finding Robots A Robotics Academy Project Louise Flannery, Laurel Hesch, Emily Mower, and Adeline Sutphen Under the direction of: Professor Chris Rogers Tufts University, Fall 2003

2. Team Spot: Motivation The Robotable The Robotable combines virtual and real world objects, allowing users to communicate and manipulate each other’s robots in a real time environment. The Robotable combines virtual and real world objects, allowing users to communicate and manipulate each other’s robots in a real time environment. A table similar Tufts Robotable is in development at Lincoln University in Christchurch, New Zealand. A table similar Tufts Robotable is in development at Lincoln University in Christchurch, New Zealand.

3. Team Spot Project Goal Develop a team of mobile autonomous robots that, within the boundary of the Robotable, will locate and travel to a spot of bright light. Develop a team of mobile autonomous robots that, within the boundary of the Robotable, will locate and travel to a spot of bright light. To relate the project to children through education outreach through the CEEO and Tufts Department of Child Development. To relate the project to children through education outreach through the CEEO and Tufts Department of Child Development.

4. Design Constraints The robots must be autonomous The robots must be autonomous No central processing unit. No central processing unit. The robots must fit onto the Robotable The robots must fit onto the Robotable Must be small enough to maneuver around the table. Must be small enough to maneuver around the table. The stationary robots must determine the position of the light and verify it using a mobile robot and to report that position to the user. The stationary robots must determine the position of the light and verify it using a mobile robot and to report that position to the user.

5. Design Idea: Triangulation 3 Robots (2 Stationary, 1 Mobile) The two stationary robots will scan 90 degrees and determine the position within the scan at which the the greatest light intensity was found. They will send this position to the mobile robot The mobile robot uses this position to determine its movement pattern. The mobile robot then travels to the identified location. St. M

6. Design Idea: Sliding Arms 3 Robots (2 Robotic Arms, 1 Mobile Robot) Robotic Arms start at (0,0) and advance out, along their specific sides- the x and y axis of the RoboTable. The arms locate the x and y coordinates with the greatest light intensity and send the information to the mobile robot. When the mobile robot has found the light spot, it reports its coordinates. ARMARM ARM X Y M

7. Design Idea: Quadrant System 4 Mobile Robot System The Mobile robots will determine which quadrant has the light spot. This quadrant will be subdivided into 4 quadrants. The within the specified quadrant mobile robot will move to the corner of its new sub- quadrant and determine which sub-quadrant holds the light spot. The other robots will move to positions on the edge of their quadrants closest to the spot of light The mobile robots will repeat this process until one converges on the light spot. Once again, upon completion the mobile robot will report its coordinates. Li gh t Sp ot M4M4 M1M1 M2M2 M3M3

8. Prototype: The Spot Finder Lego prototype. Lego prototype. Triangulation method Triangulation method RCX IR communication RCX IR communication Successes Found the position of the light using triangulation. Found the position of the light using triangulation. Developed programming methods for combining and processing data between multiple robots Developed programming methods for combining and processing data between multiple robots Areas of Improvement Need for more sturdy robots. Need for more sturdy robots. Limited range with IR communication Limited range with IR communication Lego rotation sensor unreliable for find the position of the light. Lego rotation sensor unreliable for find the position of the light.

9. Prototypes: Lego Robots Original Mobile Robot Original Stationary Robot

10. Flow Chart of Functionality Stationary robots scan for brightest light position. The position of the greatest spot is transmitted via IR to the mobile robot. Mobile robot reads in light value Interprets value using a lookup table Mobile Robot moves to correct position

11. Electrical Components There are three main electrical modules: There are three main electrical modules: Infrared Communication Infrared Communication Motor Control Motor Control Light Sensing Light Sensing These three modules were coordinated using the OOPic-R Microprocessor. These three modules were coordinated using the OOPic-R Microprocessor.

12. OOPic-R Microprocessor This microprocessor uses object oriented programming in Basic, which simplifies the programming process. This microprocessor uses object oriented programming in Basic, which simplifies the programming process. The chip includes 31 I/O pins and additional voltage sources for device interface. The chip includes 31 I/O pins and additional voltage sources for device interface. The microprocessor’s voltage source was used for IR communication, the Liquid Crystal Display (LCD), and the photo-resistor circuits. The microprocessor’s voltage source was used for IR communication, the Liquid Crystal Display (LCD), and the photo-resistor circuits.

13. Light Sensing A simple photo-resistor was placed in series with a resistor to register values of light. A simple photo-resistor was placed in series with a resistor to register values of light. This was inputted to the microprocessor using the analog to digital converter This was inputted to the microprocessor using the analog to digital converter This module’s accuracy is hampered by ambient light spots that are brighter than the light being sought. This module’s accuracy is hampered by ambient light spots that are brighter than the light being sought.

14. IR Communication While infrared communication is currently functional, it is inaccurate over long distances. While infrared communication is currently functional, it is inaccurate over long distances. High speed serial communications functionality was abandoned due to a high degree of inaccuracy. High speed serial communications functionality was abandoned due to a high degree of inaccuracy. Currently, the stationary robots send infrared pulses corresponding to the position of brightest light. Currently, the stationary robots send infrared pulses corresponding to the position of brightest light. The Mobile Robot interprets the number of pulses sent to determine the stationary robot position. The Mobile Robot interprets the number of pulses sent to determine the stationary robot position. This was the most problematic module in this project. This was the most problematic module in this project.

15. Motor Control The microprocessor controls the servo motors for both the mobile and stationary robots. The microprocessor controls the servo motors for both the mobile and stationary robots. The servos have highly variable torque, which makes the mobile robot veer to one side and the stationary robots have slightly variant positional rotation. The servos have highly variable torque, which makes the mobile robot veer to one side and the stationary robots have slightly variant positional rotation. The motion is calculated looking a look-up table using the IR received value as inputs. The motion is calculated looking a look-up table using the IR received value as inputs.

16. Motor Controller: Look-Up Table

17. Mobile Robot Powered by 2 Servo Motors Powered by 2 Servo Motors Controlled with the OOPIC-R microcontroller Controlled with the OOPIC-R microcontroller IR receiver IR receiver Liquid Crystal Display Liquid Crystal Display

18. Stationary Robot Light sensor rotates atop a DC servo motor Light sensor rotates atop a DC servo motor Controlled by OOPIC-R microcontroller Controlled by OOPIC-R microcontroller IR transmitters IR transmitters

19. Team Spot In Action

20. Team Spot in Action

21. Team Spot Webpage

22. Child Development Objectives Learn about the engineering process and the science and technology content of each Team’s robotics challenge. Learn about the engineering process and the science and technology content of each Team’s robotics challenge. Help engineers think about how to communicate and adapt their knowledge for peers without their engineering background and for children. Help engineers think about how to communicate and adapt their knowledge for peers without their engineering background and for children. Synthesize and adapt main concepts from team projects appropriately for a 4 th -6 th grade robotics curriculum. Synthesize and adapt main concepts from team projects appropriately for a 4 th -6 th grade robotics curriculum. Implement this curriculum as an after-school enrichment program in Spring 2004. Implement this curriculum as an after-school enrichment program in Spring 2004. Evaluate the process of making complex technology accessible to children. Evaluate the process of making complex technology accessible to children.

23. Course Structure Day of Introduction Day of Introduction 3 Main Phases: 3 Main Phases: Mobile robots Mobile robots Stationary robots Stationary robots Integrative final project-Treasure Island Integrative final project-Treasure Island Analysis of curriculum Analysis of curriculum

24. Team Spot: The Future IR will be replaced with blue tooth technology. IR will be replaced with blue tooth technology. Implementation of the multiple spot and moving spot problems. Implementation of the multiple spot and moving spot problems. Development of more accurate methods of scanning through 90-degrees (stationary robot). Development of more accurate methods of scanning through 90-degrees (stationary robot). Development of method for altering the inequality of the mobile robot servo motors. Development of method for altering the inequality of the mobile robot servo motors. CEEO after-school workshops in Spring 2004. CEEO after-school workshops in Spring 2004.