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Title:

Eco Car Dashboard Display

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... information to be received from EcoCar network team via serial communications link ... to one port. Chips switched on and off corresponding to data on port ... – PowerPoint PPT presentation

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Title: Eco Car Dashboard Display


1
Eco Car Dashboard Display
  • ECE 345 Senior Design Project
  • By
  • Edward Wells and Darren Shea
  • TA Ajay Patel

2
Layout of Presentation
  • Introduction to EcoCar 2000 HEV
  • Objective
  • Original Design
  • Software Overview
  • Hardware Overview
  • Costs and Labor
  • Recommendations

3
Introduction To EcoCar 2000 HEV
4
Objectives
  • Design display which is more suited to the EcoCar
    2000 HEV
  • Design dashboard to work in conjunction with
    network and cruise control
  • Retrieve information from the network
  • Display the information on a LCD display panel

5
Original Design
  • To design dashboard display suitable for Hybrid
    Electric Vehicle with backlit LCD display for
    digital information
  • Pertinent information to be received from EcoCar
    network team via serial communications link
  • Original analog speedometer and tachometer dials
    to be retained for better visualization of
    changes in these values

6
Main Software Flowchart
7
LCD Initialization Subroutine
  • Problems
  • No provided documentation
  • Pins and connector
  • LCD busy signal
  • Enable line
  • Different on-board chip

8
Displaying String Messages
  • Purpose
  • To become familiar with sending commands and data
    to the LCD display
  • Initial Demonstration

9
Speedometer LCD Output
  • Problems
  • Scaling data
  • Output input 0.5
  • Resolution
  • Trying to scale analog input should have been
    binary conversion

10
Tachometer LCD Output
  • Problems
  • Scaling data
  • Output (input 3- 65)/10
  • Same conclusion as speedometer output
  • Warning light never functioned properly, used
    non-scaled binary value

11
Analog Data Output
  • PROBLEMS
  • Tried to use same control lines with inverter for
    both Digital to Analog Converters
  • In theory, should have worked, but data not
    latched properly
  • Simpler solution, use two more control lines

12
Delay Function
  • 0.587ms time delay
  • LCD busy signal
  • 0.35 ms
  • Used delay function instead of reading LCD busy
    signal
  • Long delay(25ms)
  • for refreshing of screen

13
Analog System Overview
14
Digital to Analog Converter
  • Based on DAC 0830
  • Controlled by micro controller
  • MC1404 used for accurate reference voltage

15
DAC calculations
Iout (VREF/15k) x (Digital input)/255     VREF
(Iout x 15k)/( 15k x 255/256)   Iout
Vout/15k   Vout 4V therefore Iout 2.667
x 10-4 A   Which gives   VREF 4.016V   So
for a single step,   Iout 1.0459x10-6A
Vout 15.6882mV
16
Timing Diagram
  • Microprocessor writes to one port
  • Chips switched on and off corresponding to data
    on port
  • Data latched when WR goes high

17
Voltage to Frequency Converter
  • Provides pulse train for odometer driver
  • LF411 used as integrator for higher accuracy
  • Low tolerance, low thermal coefficient
    components, required for high accuracy

18
VFC Correction Circuit
  • Non-inverting amplifier
  • High gain to clean pulse train
  • Adjustable off set to make pulse train positive

19
VFC calculations
Fout (-Vin/2.09) x (Rs/Rin) x (1/RtCt)   Max
input voltage -4.1V Max required frequency
90Hz   Rs 12.1k Rin 100k Ct 0.01uF   90
(4/2.09) x (12.1/100) x (1/(Rt x
0.01x10-6)   Rt 257.3k?   The closest value
in the E12 series is 220k?
20
Odometer Driver
  • CS8441 odometer driver
  • Frequency input
  • Calculates correct sequence for stepper motor

21
Gauge Controller
  • CS8190 air core gauge driver
  • Voltage input used instead of frequency
  • LF411 drives voltage into chip bypassing
    frequency conversion circuits

22
Costs Labor
Labor Typical EE entry salary 50,000/year 1
year / 240 days 1 day / 8 hours
26/hour 26/hour 2.5 150 hours 9,750per
person Total Labor
19500 Parts LCD display 38 68HC11
Microcontroller 30 Resistors,
Capacitors 5 DAC 0830 7.08 x2 LM331
8.16 LF411 1.27 x 3 LM741 0.46 x4 CS8190
2.80 x 2 CS8441 2.00
Total Parts 108.57
Total Costs 19,608.57
23
Recommendations
  • Wanted to interface with network and cruise
    control teams, display in EcoCar
  • Backlit LCD display
  • Add more functionality
  • e.g. More warning lights, more complex LCD
    display
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