Computer Engineering Tethered Car Project University of Waterloo Summer Institute 2005

1
Computer Engineering Tethered Car
ProjectUniversity of WaterlooSummer
Institute2005

• Graham Smyth
• smythel_at_mnsi.net

2
Computer Engineering Units
Grades 10 - 12 Five Hands-0n Units

• 1. Hardware
• 2. Networking
• 3. Integrated Circuits
• 4. Programming
• 5. Interfaces

3
Tethered Vehicle Approach

• LEDs
• DC Power Supply
• Transistors
• Uni-direction motor
• Bi-direction motor
• Single motor vehicle
• Two motor vehicle
• Hand built vehicle
• Additional Features (head lights, tail lights,
  turn signals, fog lights etc)

4
Hardware

• Computers parallelport through D sub connector
• D sub to interface (transistors, resistors,
  diodes)
• Interface to motor (in car)

5
Software
Turing

• parallelput ( number)
• put parallelget
• mousewhere ( x, y, click)
• play (CDEFG)
• drawline ( x1, y1, x2, y2, red)
• Provincially Licensed

6
Bidirectional Motor Interfacing Hardware

• vehicle with DC motor
• tethering ribbon cable 2 meters
• D sub 3 pair wire
• solid core wire various, short
• 2 TIP 31s
• 2 TIP 42s
• 1 D sub connector
• 12 male pins
• 9 V DC power supply (white is )
• 1 breadboard
• 4 1K resistors (Brown/black/red)
• 2 diodes (1N401)
• LEDs

7
Breadboard in Detail
Top Rail Connected
Connected In Fives
Bottom Rail Connected
Divider
8
Interfacing System Unit 5
Computer Interface Peripheral

• Parallelport

• Wires
• Diodes
• Resistors
• Transistors

• Vehicle

Wires
Wires
9
Parallelport Pin Configuration(printer port)
Input I0 I3
Output D0 D7
13 12 11 10 9 8 7 6
5 4 3 2 1
25 24 23 22 21 20 19 18 17
16 15 14
Input I4
Grounds 18 - 25
View from back of Computer
10
Interface Wire
Male Pin
Insulated Wire
Stripped Wire
Crimp Tabs
11
Transistor TIP31 42Physical
Schematic
Emitter Base Collector (Right Left
Middle)
Base Collector Emitter
12
Disassembling Tips

• Leave wire long on remote board
• Put car on blocks (gears dislodge)
• Ribbon cable through antenna hole
• Knot ribbon cable on interior post of car
• Feed cable through antenna hole
• carefully strip ribbon cable

13
Ribbon Cable Configuration
Wire FUNCTION 1 Ground 2
Head and spot lights 3 Right rear signal
4 Left rear signal 5 Motor 6 Motor -
marked
14
Disassembling the Vehicle (with care)
Remove Three Screws
2
1
3
15
Separate Frame Halves
4. Clip 3
3. Clip 2
1. Remove Aerial
2. Clip 1
Spread Clips Carefully
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Access Motor Leads
2. Cut Red/Black Wires
3. Strip Black Wire
4. Strip Red Wire
1. Place Upper Body on Lower
17
Attach Ribbon Cable
1. Strip All Wires
3. Tie Cable to Post
4. Wrap Red Wire to Ribbon Wire 5
5. Wrap Black Wire to Ribbon Wire 6
2. Mark 6th Wire
6. Tape Two Motor Wires
18
Replace Frame Halves
Snap Body Together
Feed Cable Through Antenna
19
Re-attach Body
2. Feed Cable Through Antenna
3. Re-attach Body with 3 Screws
1. Identify 6th Wire
4. Attach Male Pins to Wire 5 6
20
Wiring Interface Cable
1. Attach Male Pins to the Orange/Blue/Green
Wires
2. Strip 1cm from the Orange/Blue/Green Wires
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D sub
1. Attach Wiring Harness
2. Insert Blue Wire Into pin 2
4. Insert Green Wire Into pin 18
3. Insert Orange Wire Into pin 3
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Wiring Interface Transistors
TIP42
TIP42
White Stripe
-
TIP31
TIP31
23
Wiring Interface DiodesBack View
3. Diode Direction
1. Middle Pin of 42
2. To Middle Pin of 31
4. Repeat Steps 12 for diode 2
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Wiring Interface Resistors
5. Repeat Steps 12
6. Repeat Steps 34
3. Left Pin of 31

• Left Pin of 42
• (Viewed from front)

4. To Any Spot
2. To Middle Pin of 31
25
Wiring Interface
3. Repeat Steps 12

• Left Pin of 42 (back view)

2.
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Wiring Interface Ground
3. Repeat Steps 12
2. -
1. Right Pin of 31
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Wiring Interface D sub

• Resistor to
• Pin 2 of D sub

3. Ground to Pin 18 of D sub
2. Resistor to Pin 3 of D sub
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Wiring Interface Ribbon Cable
2. To Middle Pin of 42
4. To Middle Pin of 42
1. Wire 6
3. Wire 5
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Bidirectional Motor Software

• Write a program to control the car such that when
• 1 is pressed the car moves backward
• 2 is pressed the car moves forward
• 3 is pressed the car stops.

30
Bidirectional Motor Software
var answer int var key string (1) put 0 is
stop, 2 is forward, 1 is reverse loop getch
(key) cls answer string (1) if answer 1
then parallelput (answer) put
REVERSE elsif answer 2 then parallelput
(answer) put FORWARD elsif answer 0
then parallelput (answer) put STOP end
if exit when answer 0 end loop
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Additional Features

• Additional options could include
• Separate left and right tail lights
• Head lights
• Search lights on roof
• Software control of all lights individually
• Backup lights
• Audio backup signal

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Addresses
smythel_at_mnsi.net www.classictechnology.ca www.ho
ltsoft.com