ECE 477 Design Review Group 7  Spring 2005

Outline Project overviewProject overview Project-specific success criteriaProject-specific success criteria Block diagramBlock diagram Component selection rationaleComponent selection rationale Packaging designPackaging design Schematic and theory of operationSchematic and theory of operation Preliminary PCB layoutPreliminary PCB layout Software design/development statusSoftware design/development status Project completion timelineProject completion timeline Questions / discussionQuestions / discussion

Project Overview An autonomous vehicle designed to look for moving heat-emitting targets and engage them while patrolling a limited area and avoiding ground obstacles. +=

Project-Specific Success Criteria An ability to detect a heat-emitting targetAn ability to detect a heat-emitting target An ability to determine and display the number of engagements and battery levelAn ability to determine and display the number of engagements and battery level An ability to fire the weaponAn ability to fire the weapon An ability to turn weapon to face targetAn ability to turn weapon to face target An ability to avoid collisions with inanimate objectsAn ability to avoid collisions with inanimate objects

Block Diagram Freescale HC(S)12 (1) Servo motor (1) Passive IR sensors (4) Ultrasonic sensor (1) LCD screen/Shift Register (1) AirSoft gun (1) H-Bridge for Drive Motors (1)

Component Selection Rationale MicrocontrollerMicrocontroller Ultrasonic SensorsUltrasonic Sensors Passive Infrared Sensors (PIR)Passive Infrared Sensors (PIR) Robot BaseRobot Base Liquid Crystal Display (LCD)Liquid Crystal Display (LCD) Servo MotorServo Motor Paintball GunPaintball Gun

Component Selection Rationale Micro-controller: Motorola M68MOD912C32Micro-controller: Motorola M68MOD912C32 - Pre-made DIP Module - Contains requisite I/O - Instruction Set/Capability Familiarity

Component Selection Rationale Ultrasonic Sensors: Devantech SRF04Ultrasonic Sensors: Devantech SRF04 - Ease of use - Small size - Low cost

Component Selection Rationale Passive Infrared Sensors: Kitsrus K30Passive Infrared Sensors: Kitsrus K30 - Easy to interface. - Good range ( Approx. 120 degree spread ) - Low cost

Component Selection Rationale Robot Base: Rogue Robotics RT-ATRRobot Base: Rogue Robotics RT-ATR - Easy to control ( 2 geared motors ) - Flexible/Expandable design - Multiple levels - Came with H-bridge

Component Selection Rationale Liquid Crystal Display: Optrex DMC20261ALiquid Crystal Display: Optrex DMC20261A - Free - 20 Chars x 2 Lines - Backlit - Heavy-duty

Component Selection Rationale Servo Motor: JR NES-537Servo Motor: JR NES Easy to interface/operate compared to stepper motor - High torque rating ( 45 oz-in ) - Very small/lightweight - Low cost degree range degree range

Component Selection Rationale Paintball Gun: KTC Paintball Gun: KTC Fully Automatic - Electronic Trigger - Small ( 9” after cut down ) - Light weight ( less than 1 lb ) - Easily interfaced

Packaging Design – Front View

Packaging Design – Side View

Schematic/Theory of Operation Voltage regulatorsVoltage regulators LCD interfaceLCD interface PIR interfacePIR interface Ultrasonic sensor interfaceUltrasonic sensor interface Servo interfaceServo interface H-Bridge and drive motors interfaceH-Bridge and drive motors interface Gun trigger interfaceGun trigger interface Battery level indicatorBattery level indicator

Schematic/Theory of Operation – Voltage Regulators Power supply for microcontroller module and other digital components:Power supply for microcontroller module and other digital components: –Linear Tech LT switching regulator –Step down from 14.4 V input to 5 V regulated output –Can supply up to 1.25 A current –Up to 88% efficiency, typically around 86%

Schematic/Theory of Operation – Voltage Regulators 10  H Inductor because the current draw could be more than 0.6 A10  H Inductor because the current draw could be more than 0.6 A

Schematic/Theory of Operation – Voltage Regulators Power supply for motors:Power supply for motors: –Linear Tech LT switching regulator –Step down from 14.4 V input to 5 V regulated output –Can supply up to 4.25 A current –Up to 90% efficiency, typically around 88%

Schematic/Theory of Operation – Voltage Regulators 10  H Inductor because the current draw could be more than 3.5 A10  H Inductor because the current draw could be more than 3.5 A

Schematic/Theory of Operation – LCD interface Utilizes the SPI capability of the MCUUtilizes the SPI capability of the MCU A shift register, 74HC164, will be used to register data to be displayed on the LCDA shift register, 74HC164, will be used to register data to be displayed on the LCD Pin PM5 will be used to supply SCK to the shift registerPin PM5 will be used to supply SCK to the shift register Pin PM4 will be used to supply SDO to the shift registerPin PM4 will be used to supply SDO to the shift register Pin PM3 will be used to supply RS to the LCD modulePin PM3 will be used to supply RS to the LCD module Pin PM2 will be used to supply Enable to the LCD modulePin PM2 will be used to supply Enable to the LCD module A 7x2 header will be used to connect LCD to the PCBA 7x2 header will be used to connect LCD to the PCB

Schematic/Theory of Operation – LCD interface

Schematic/Theory of Operation - PIR interface Four PIR (passive IR) sensors to detect heat emitting moving objectsFour PIR (passive IR) sensors to detect heat emitting moving objects AN0 to AN3 will be used to receive the inputs from the sensorsAN0 to AN3 will be used to receive the inputs from the sensors 9 V pulse when a heat emitting moving target is detected9 V pulse when a heat emitting moving target is detected A voltage divider is used to reduce the voltage input to the MCU to 5 VA voltage divider is used to reduce the voltage input to the MCU to 5 V Resistors with the values of 1 k  and 1.2 k  will be used as the voltage dividerResistors with the values of 1 k  and 1.2 k  will be used as the voltage divider

Schematic/Theory of Operation - PIR interface Vout = (R below /(R up +R below )) * V in 5 = ( R below /( R up +R below )) * 9 R below /( R up +R below ) = 5/9 1.2 k  / (1k  k  )  5/9

Schematic/Theory of Operation - Ultrasonic interface PT7 will output trigger pulse to the sensorPT7 will output trigger pulse to the sensor PT6 will receive the input pulse from the ultrasonic sensorPT6 will receive the input pulse from the ultrasonic sensor Distance is determined by how long the input pulse is held highDistance is determined by how long the input pulse is held high

Schematic/Theory of Operation - Servo interface Pin PT4 will be used to output pulses regulated by the built-in PWM to the servo to rotate the gun turretPin PT4 will be used to output pulses regulated by the built-in PWM to the servo to rotate the gun turret Wiring setup image courtesy of Parallax, Inc.Wiring setup image courtesy of Parallax, Inc.

Schematic/Theory of Operation - H-bridge and motors interface PT0 to PT3, will be used as output pins to the H-bridge to drive the direction of the robot and PWM will be used to control the speed of the motorsPT0 to PT3, will be used as output pins to the H-bridge to drive the direction of the robot and PWM will be used to control the speed of the motors Drive motors will be connected and powered through the H- bridgeDrive motors will be connected and powered through the H- bridge The power supply to the drive motors will be regulated by the LT converterThe power supply to the drive motors will be regulated by the LT converter The H-bridge’s power will be regulated by the LT converterThe H-bridge’s power will be regulated by the LT converter H-bridge image courtesy of Rogue RoboticsH-bridge image courtesy of Rogue Robotics

Schematic/Theory of Operation - Gun trigger interface PM0 will be used as triggerPM0 will be used as trigger The gun will be optically isolated from the MCUThe gun will be optically isolated from the MCU 4N28 opto-isolator will be used4N28 opto-isolator will be used

Schematic/Theory of Operation - Battery level indicator AN4 will be used to receive an analog voltage reading from the power supply to indicate the current level of the batteryAN4 will be used to receive an analog voltage reading from the power supply to indicate the current level of the battery 10-bit analog input and the analog to digital (A/D) converter will convert the input voltage to a digital value that can be used to compute the current battery level10-bit analog input and the analog to digital (A/D) converter will convert the input voltage to a digital value that can be used to compute the current battery level Will be displayed on the LCDWill be displayed on the LCD A voltage divider is used to reduce the voltage input to the MCU to maximum 5 VA voltage divider is used to reduce the voltage input to the MCU to maximum 5 V Resistors with the values of 2.2 k  and 1.2 k  will be used as the voltage dividerResistors with the values of 2.2 k  and 1.2 k  will be used as the voltage divider

Schematic/Theory of Operation - PIR interface Vout = (R below /(R up +R below )) * V in 5 = ( R below /( R up +R below )) * 14.4 R below /( R up +R below ) = 5/ k  / (2.2 k  k  )  5/14.4

Preliminary PCB Layout

Software Design Software Design Target Detected? Display Engagements Poll PIR Sensors Poll Ultrasonic Sensor Obstruction Detected? Turn Motors ON FWD Turn 90 o Right Turn Motors OFF Stop Turret Fire Weapon Set Engagement Flag Engagement Flag Set? Increment Engagement Count on LCD Pause for 10 Seconds Clear Engagement Flag Spin Grover 180 o Turret Sensor Triggered? Turn Maxed? Turn Turret Right Turn Turret Left Stop/Reset Turret Reset Gun Clear LCD Start Which PIR Sensor? Yes Turn Motors OFF Yes No Display Battery Level Spin Grover 90 o in Same Direction

Project Completion Timeline Week Project Completion 8 - Finish PCB layout and fit parts to printout - Receive final O.K. from Chuck 9 SPRING BREAK (Gambling in VEGAS!) 10 - Start mounting parts to PCB - Continue with software prototyping 11 - Start interfacing software with hardware 12 - Finish up on packaging with gun turret and servo motor mount 13 - Finish software interfacing - Begin working on user manual 14 - Finish user manual - Work on demonstration video and final presentation 15 - Final Presentation

Questions?