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Critical Design Review Dayrider

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Tim Ikenouye, Kieran Tie. 8/31/09. CDR - Team Dayrider. 2. Objectives. Minimum: A solar-powered, ... Optimal: A vehicle that combines efficient design, ... – PowerPoint PPT presentation

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Title: Critical Design Review Dayrider


1
Critical Design Review - Dayrider
  • Team Dayrider
  • George Jenny, Amjad Sawaged,
  • Tim Ikenouye, Kieran Tie

2
Objectives
  • Minimum A solar-powered, router-controlled RC
    vehicle
  • Target A self-controlled software-sensor
    interface with regenerative techniques for energy
    recapture measurements
  • Optimal A vehicle that combines efficient
    design, functional power management, and a
    dynamic user interface in an aesthetically
    pleasing package

3
Status
  • Components selected and shipping
  • Preliminary wire-wrapping of modular pieces
    (ADCs)
  • Control software of the MSP430 I.P.
  • Schematics main board, subsystems sketched out
    and transferring to Altium
  • Router hardware/software modifications completed

4
Block Diagram
5
Motor - Traxxas Stinger 540
  • 20-turn DC brushed motor
  • 1.5A at 3V no load
  • 33mA at 500 mV reverse
  • Already standard on the current chassis

6
Battery STAAB
  • 6V output
  • 3.4 Amp-hour capacity
  • 7-7.5 rated charging V
  • 0.692 kg
  • 134mm/34mm/60mm

7
Solar Panels
  • 7.2 V _at_ 200 mA
  • Thickness 0.6mm (24 mil)
  • Total Size 253mm x 150mm
  • Weight-25.9g

8
Microcontroller - TI MSP430F1611
  • 16 bit RISC CPU
  • 8 MHz operational frequency
  • 48 KB Flash, 10 KB Ram
  • 48 GPIO pins
  • Analog Comparator, DMA
  • Hardware Interface
  • 2 UART or SPI for hardware Interface (USART 0,
    USART1)
  • I2C mode for peripheral interface

9
Microcontroller - TI MSP430F1611
10
Modular Peripherals
  • Hardware addressed on each peripheral board
  • Plug and Play onto main board
  • Modularized design allows for easier assembly and
    debugging
  • I2C Bus supports 7 and 10 bit addressing modes
    (p308 user guide)

11
I2C Bus
  • Basic implementation of I2C Bus
  • Must be implemented in USART0

12
USART0 Control Register
RXDMAEN - Transmit data from I2C via DMA upon
receiving data SYNC (1) for SPI or I2C mode,
(0) for UART mode I2C (1)selects I2C mode when
SYNC 1 I2CEN enables(0) or disables(1)
operation of I2C mode MST selects master (1)
or slave (0) mode
13
I2C Timing Diagrams
One clock pulse is generated by the master device
for each data bit transferred. The I2C module
operates with byte data. Data is transferred
most significant bit first as shown in Figure
15.3
STOP Condition SDA Low to High while SCL is
High
START Condition SDA High to Low while SCL is High
Change of Data only allowed while SCL is Low,
otherwise START and STOP conditions are generated
14
I2C Addressing Scheme
Start Condition
Stop Condition
Acknowledge bit sent by receiver after each byte
Direction of data flow on SDA can be changed by
master by issuing a repeated start condition
RESTART is issued, slave address issued with new
value for R/W bit
15
Motor Controller - LMD18200T
  • Controlled using PWM by additional MSP430F2003TN
    connected to I2C bus
  • Steering mechanism 5 V supply servo motor, dead
    straight D 50, f 392 Hz _at_ 1 V, modulating D
    from 40 60 steers left to right.

Functional diagram
16
Motor Controller Schematic
3 inputs to motor controller supplied by smaller
MSP430F2003
17
Analog to Digital Converter - PCF8591
  • Operating supply voltage 2.5 6 V
  • Serial throughput of data via I2C
  • 4 Analog input programmable with multiplexer
  • Addressing via 3 hardware addressing pins
  • Sampling rate given by I2C bus speed

Programmable hardware bits
18
ADC schematic
  • 4 input ports
  • I2C interface
  • 3 programmable hardware bits

19
Light-to-Voltage Converters - TSL14S
  • Converts light intensity to output voltage
  • Single supply operation 2.7-5.5V
  • Connect to PCF8951 ADC
  • Mount along perimeter of car

Output pulse falling edge
Output pulse delay rising edge
Output pulse fall time
Output pulse rise time
20
TSL14S LVC schematic
  • 4 LVCs connected directly into ADC
  • We will have 2 of these modules for a total of 8
    LVCs

21
Range Sensors - MaxSonar EZ1
  • Analog 10mV/inch output
  • Detection from 0 255 inches (20 ft.)
  • Single 5V power supply
  • Very low power draws only 2mA
  • lt ½ the size of other sensors in its class
  • Connect to PCF8951 ADC

22
Range Sensor Schematic
  • All 3 sensors multiplexed in 1 ADC
  • Same ADC used throughout all peripheral modules

23
Parts List
  • Assembled chassis with motor
  • STAAB deep cycle battery (2)
  • Traxxas Stinger 540 motor
  • Solar Panels
  • Linux router
  • MAX233a level converters
  • HAC-UM96 wireless transceivers
  • MSP430F1611 microcontroller
  • MSP430F2003 microcontroller
  • LMD18200T motor controller
  • PCF8591 ADCs
  • TSL14S light to voltage converters
  • MaxSonar EZ1 range sensors
  • Sparkfun F1611 Dev board

24
Serial Communication - MAX233e
  • Converts TTL/CMOS levels coming from
    router/microcontroller to RS232 levels for
    computer/HAC-UM96
  • 2 needed - one for router, and one for
    microcontroller/UART

25
Serial Communication - HAC-UM96
  • 96kbps wireless transceivers
  • Transmission power 10mW
  • 433MHz frequency
  • Range 300-500m
  • Takes TTL or RS232 inputs - will use RS232 for
    ease of debugging

26
Software - MSP430
  • Written in C / Assembly
  • Developed using IAR Embedded Workbench
  • Tested on prototyping board from Olimex
  • Final version transferred to main circuit
  • No software yet, but

27
Software - MSP430
  • Use Cases - Outline software algorithms for the
    operation of the vehicle
  • UC1 - Avoid Obstacle
  • UC2 - Drive to Sunlight
  • UC3 - Drive Vehicle
  • Test cases for all possible paths of use cases
  • Domain model under construction

28
Software - Linksys WRT54G
  • Linux - OpenWRT
  • lighttpd - web server
  • Ajax - live updating of site
  • PHP - system commands
  • Serial data processor

29
Web Interface - Concept
30
Web Interface - Demo
31
Division of Labor
  • Software Kieran Amjad
  • Users Interface (webpage)
  • Autonomous Control
  • Peripherals
  • Hardware Tim George
  • Wire-wrap board
  • Peripherals
  • Regenerative Braking

32
Milestone 1 November 2
  • Preliminary MSP430 code
  • Serial communication between vehicle and router
  • Moving Vehicle

33
Milestone 2 November 30
  • Completely Solar/Battery Powered
  • User control of Vehicle
  • Range Sensors

34
Expo December 14
  • Energy Regeneration
  • Peak Power Tracking

35
Schedule
36
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