1. D.A.V.E.
Robot Construction Project
Lara Cowan
Victor Johnson
Hector Malagon
Michael Zaw

2. Following Lines
• Simple device structure
• Basic algorithm
• Many ways to implement design

3. Research & Development

4. The Robot

5. Overview
• Sensory systems
– Data input systems; Collect information of outside
world
• Data processing/motor control
– Systems to interpret input signals and decide what to do
• Drive systems
– Output systems for machine; Implement signals from
motor controller

6. Sensory Systems
• Photoresistors
• Phototransistors
• Photodiodes

7. Photoresistors
• Resistance is inversely
proportional to light levels
• Cheapest of the three types
of photoconductive devices
• Have the slowest reaction
rate of all photodetectors

8. Phototransistors
• Current is sourced in the
presence of light
• Moderately priced
• Respond about 1000 times
faster than photoresistors

9. Photodiodes
• Current is sourced in the
presence of light
• Most expensive class of
photoconductors
• Respond about 1000 times
faster than photoresistors

10. Data Processing &
MotorControl
• Algorithm
• Programmable logic device
• Microcontroller

11. Line Following Algorithm
• Robot direction is determined by what the
robot “sees”
– If line is centered in front of robot, go forward
– If line is left of center, turn left
– If line is right of center, turn right
– If no line is detected, circle until line is found

12. Line Following Algorithm
• Straight
• Left
• Right
• Circle

13. Programmable Logic Device
(PLD)
• Relatively inexpensive
• Can easily implement finite state automata
• Has limited program capacity
• Has limited program capabilities

14. Microcontroller
• Costlier than PLD
• Relatively easy to program
• Memory can be expanded, if needed

15. Drive Systems
• DC motor
• Stepper motor
• Servo motor

16. DC (Toy) Motors
• Abundant and cheap
• Easy to implement
• Provide no feedback
regarding motor speed or
position

17. StepperMotors
• Expensive
• Require special circuitry to
implement
• Provide no feedback
regarding motor speed or
position

18. Servo Motors
• Very expensive
• Provide feedback data
• Require sophisticated
algorithms to implement

19. Research & Development

20. Phototransistors
• Cost less than photodiodes
• Have better reaction time than
Photoresistors

21. PLD
• Cheaper than microcontroller
• More appropriate, given program size

22. DC Motor
• Cheap
• Will be run continuously
• Does not need advanced features of servo

23. THEEND