1. Lecture 15 Line Tracer
Hong, DGU

2. Line Tracer

5. Line Tracer Configuration
Sensors : Detect the Road Situation
CPU : Determines the Direction to Move and Generate Corresponding Signals
Motors and Wheels

6. Direction to Move if left=white, center=black, right=black
then turn right
if left=white, center=black, right=white
then go straight

7. So
Go straight
Turn Left
Turn Right

8. Infrared Sensor Detector the lights with 0.75mm ~ 1mm waves
Consists of Transmitter and Receiver
Most remote controllers for consumer electronics have transmitter and the sets have receiver
Auto doors, auto lights and motion detectors include both ; transmitter sends out the infrared signal and the receiver detects the response

9. Infrared Sensor for Line Tracer
White floor reflects the infrared signal
Black floor absorbs the infrared signal
Warning) If you keep turning on the infrared transmitter too long, the lifetime of the device will be reduced or the device can be damaged.

10. DC Motor Driver IC Motor requires huge current for the operation.
Not only CMOS but also TTL is not strong enough to provide such big current.
Sometimes DC motors generate reverse current toward the driving chip.
Therefore special DC motor driver IC is need (Ex. Sanyo LB1630.)

11. Pseudo Code
Pseudo-code is a way of expressing an algorithm in similar style of C code.
Do not worry about detail grammar. We will not compile anyway.
You can even create a your own function name.
direction ( ) {
if (sensor input is 001) ….
else if

12. Homework
Write a pseudo code to illustrate the operation of the line tracer.
You need to define proper variables and come up with an algorithm.