DESIGNERS: Jennifer Andrade Warren Hirschbuehler Scott Hansen Ronald Estacio Erik Marshall

1. DESIGNERS: Jennifer Andrade Warren Hirschbuehler Scott Hansen Ronald Estacio Erik Marshall Senior Project December 2nd, 2004

2. Table of Contents • Background • Challenge • Electrical/Mechanical Tasks • Scout Chassis • Power Supply Design • Receiver/Transmitter Design • Motor Control • Programming Hurdles • Speed Control • Line Following • Obstacle Avoidance • “Bomb” Location • “Bomb” Disarming • Timeline • Budget • Recap • Contact Information

3. Electrical/Mechanical Tasks • Scout Chassis: • Rear wheel differential steering • Two rear driving wheels • Benefits: • Ease of control when turning • Fewer Motors reduces power consumption • Pushing increases traction on inclines

4. Electrical/Mechanical Tasks (cont) • Scout Chassis: • Main plate angled downward • Benefit: • Reduces chance of flipping when on incline

5. Electrical/Mechanical Tasks (cont) • Scout Chassis: • Sonar Turret • Mounting • 25K Ultrasonic Receivers • 40K Ultrasonic Transmitter and Receiver • Infrared Transmitter and Receiver • Servo Motor • Controlled by FPGA

6. Electrical/Mechanical Tasks (cont) • Scout Control: • FPGA • What is a FPGA? • Field Programmable Gate Array • FPGA Acts as the “Brain” • Digilent Spartan 3 • 200,000 Transistor Level Gates • Programmable RAM • Large Number of I/O’s for Peripherals

7. Electrical/Mechanical Tasks (cont) • Power Supply Design: • Source: • 14.4 Vdc Battery • Dependants: • Motors • 14.4 Vdc (pulse modulated) • Sensors (IR and Ultrasonic) • 5 Vdc • IR Transmitters • 5 Vdc • Ultrasonic Transmitters • 5 Vdc • FPGA Board • 5 Vdc

8. Electrical/Mechanical Tasks (cont) • Power Supply Block Diagram: Battery POWER SUPPLY 14.4 Vdc 14.4 Vdc 5 Vdc Ultrasonic Transmitter Left Motor Left H-Bridge Digilent Spartan 3 IR Sensors Right Motor Ultrasonic Sensors Right H-Bridge FPGA Encoders Comms 14.4 Vdc 5 Vdc

9. Electrical/Mechanical Tasks (cont) (1) 7805 • 2 3 LM317 • 2 3 F2 F1 +Batt +5v out #1 C1 0.1µF C2 0.1µF C3 0.1µF R2 240 R3 1550 R1 (2) 7805 • 2 3 R6 F3 +5v out #2 C4 0.1µF R4 (3) 7805 • 2 3 F4 +5v out #3 C5 0.1µF R5 • Power Supply Schematic:

10. Electrical/Mechanical Tasks (cont) • Receiver/Transmitter Design: • Receivers: • Infrared • Mine code detection • Ultrasonic • Mine detection • Transmitters: • Infrared • Mine code disabling • Line Detection Pegasus Comparator Sensor Amplifier

11. Sensor Amplifier Pegasus Comparator Transmitter Driver Electrical/Mechanical Tasks (cont) • Sensor/Transmitter Design: • Transceivers: • Infrared • Encoders • Line followers • Ultrasonic • Obstacle avoidance

12. Electrical/Mechanical Tasks (cont) Barrier 40k Hz . . . Start clock • Ultrasonic Transmitter 40k

13. Electrical/Mechanical Tasks (cont) Barrier Distance = (Dt) x (speed of sound) ∆t ∆d 2 Reflection • Ultrasonic Receiver 40k

14. Electrical/Mechanical Tasks (cont) 25k Hz L BOMB R R = L = ∆t • Ultrasonic Receiver 25k

15. Electrical/Mechanical Tasks (cont) L BOMB R L= ∆t≈O R= • Ultrasonic Receiver 25k

16. 5v 14.4 v R2 R1 33078 + _ From FPGA Output (to Transmitter) 5v R3 R4 R5 Electrical/Mechanical Tasks (cont) • Ultrasonic Transmitter Schematic

17. +5v 5v +5v +5v R6 R8 2 From Receiver _ 1 8 + 3 7 5v R7 +7 -6 From FPGA RG1 AD623 6 5 5v LM 339 4 3 Electrical/Mechanical Tasks (cont) • Ultrasonic Receiver Schematic

18. Electrical/Mechanical Tasks (cont) Full Signal • Infrared Transmitter/Receiver

19. Electrical/Mechanical Tasks (cont) Full Signal Zoom • Infrared Transmitter/Receiver

20. Electrical/Mechanical Tasks (cont) • Motor Control: • Motors: • Gearbox - 64.4 : 1 DC • Encoders: • IR Transceivers • Look-across sensors • FPGA: • Interfaces with H-Bridge • Speed and Direction • Pulse width modulation • Encoders

21. Electrical/Mechanical Tasks (cont) • Motor Control:

22. Programming Hurdles • Speed Control • Encoder Interaction • Line Following • Differing States of Line Sensors • Obstacle Avoidance • Obstacle Location • Avoidance Algorithm • Turret Control

23. Programming Hurdles (cont) • “Bomb” Location • Lock-In Vs Obstacle Avoidance (Ultrasonic) • Turret Control • “Bomb” Disarming • Determining Bomb Code (IR) • Bit Manipulation • Bomb Disabling

24. Timeline

25. Budget • For time, materials, and research, an initial investment of two-hundred fifty dollars will be required to bring this project to fruition. • This low budget is to produce a robot that is an inexpensive alternative to current options.

26. Recap • Background • High cost and casualty creates a need for alternative • Tasks • Scout Chassis • Two wheel differential rear drive • Power Supply Design • Multiple voltage requirements • Sensor/Transmitter Design • IR and Ultrasonic sensors multiple uses • Motor Control • FPGA / H-Bridge driven with encoder feedback • Timeline • Several concurrent processes being done simultaneously • Budget • Low budget

27. Contact Information • San Diego State University • Electrical and Computer Engineering Dept. • 5500 Campanile Drive • San Diego, CA 92182 • www.scout.sdsu.edu • scoutindustries@yahoo.com