COLMAC Line Follower Robot Racing User manual
Line Follower Robot Racing
Build
Program
Race!
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The COLMAC Line Follower Robot has been developed
as a low cost introductory model for students and
educators interested in Robotics.
Line follower robots are used extensively in industry
in areas where parts or materials need to be
constantly delivered from one location to another.
Generally known as AGVs (Automated Guided Vehicles) they are found mainly in the car
manufacturing industry and anywhere that employs large warehousing where the robot follows
tracks to and from the shelves they stock and retrieve from.
The COLMAC line follower robot kit has the following features:
Simple chassis made from acrylic sheet.
Two wheeled easily controlled differential drive and steering.
Significant distance between line sensors and wheels allowing the robot time to react and
reduce the instances of over-shooting.
Line illumination LED.
The following should be noted when using this robot:
All the settings for the LDR sensors indicated in the notes are examples only. Each robot will
require its own settings for the sensors to be found through calibration. They will depend
on the surface it is operating on, the colour of the line being followed, the charge in the
batteries etc. and indeed similar LDRs will differ slightly from each other.
This robot is also suitable for entering the annual Robotics Ireland ©Robot Games Ireland
Tournament in the Line Follower Racing category. See www.colmac.ie for further details.
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Table of Contents
1. Assembling the Line Follower Robot Kit……………………………………………………….................. 3
2.Downloading/Installing GENIE Programming Editor Software ....................................... 21
3. GENIE Programming Editor Interface ........................................................................... 22
4. Connecting the E18 Motor Control Board to your computer......................................... 23
5. Testing the E18 Motor Control Board........................................................................... 24
6. Driving the robot forward/reverse............................................................................... 29
7. Turning the robot ........................................................................................................ 32
8. Using the LDRs to detect a line .................................................................................... 35
9. Using the LDRs to follow a line .................................................................................... 43
10. Using a defined loop during a program ...................................................................... 45
11. GENIE Programming Editor Help ................................................................................ 48
12. Troubleshooting Tips ................................................................................................. 49
13. Improving your Line Follower racing……………………………………………………………………………53
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1. Assembling the Line Follower Robot Kit
The following tools which are not supplied are the minimum necessary in order to build the robot:
Minimum 25Watt soldering iron and stand –solder is
supplied in the kit.
Small long nosed pliers suitable for electronics.
These can be used for manipulating small components and
stripping cable insulation.
They can also be used for trimming the legs of components once
they have been soldered into the printed circuit board (PCB).
Some method of holding the GENIE E18 printed circuit board (PCB) while components are being
soldered is very useful. Some examples are shown below:
Assembly aids and small vices are
ideal but any method that holds the
PCB while the component is being
soldered is ideal –pieces of Blu-Tack
can even be used!
SAFETY NOTICE
Never touch tip of soldering iron –it will burn you!
Always return iron to its stand when not in use.
Wear eye protection –solder can ‘spit’
Avoid inhaling fumes –work in a ventilated area
Ensure all parts of the equipment are damage free
See www.colmac.ie for soldering technique video and
other related videos e.g. cable stripping etc.
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The first step is to populate and solder all the components on to the GENIE E18 Motor Control
Board.
When completed, this board is a PIC micro controller. Peripheral Interface Controllers (PIC) are
small computers that can be programmed and reprogrammed using the GENIE Programming Editor
programming language to turn on/off various outputs depending on the state of various inputs.
The outputs being controlled in this case are:
2 x DC motors used to drive and steer the robot
1 x LED used to illuminate the line being followed
The inputs used to control these outputs are:
2 x LDR (Light Dependent Resistors) that act as line following sensors
The processing of all the information from the inputs and the control of the outputs is done by:
1 x GENIE E18 PIC Microcontroller Chip (18 pin shown in red above)
The motors are driven forward/reverse or clockwise/anti using a motor driver chip:
1 x L293D Motor Driver Chip (16 pin shown in yellow above)
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Step 1: Solder in the fixed resistors.
Resistors reduce the flow of electric current and also change the voltage level at different parts of
the circuit. Their size is measured in Ohms (Ω) and usually in thousands of Ohms or Kilo Ohms –this
is usually just written as K e.g. 22K = 22 Kilo Ohms
Fixed resistor size is shown using colour code: http://en.wikipedia.org/wiki/Electronic_color_code
The colour coding of all resistors used in the E18 board is shown below.
Fixed resistors have no polarity i.e. no positive or negative (+ or –) and so can be inserted either
way around.
Insert the resistors in their correct places either
way around as they don’t have a positive or
negative (+ or -).
The size of each resistor is marked on the board and their colour coding is as follows:
0 Ohm –Black –Marked ‘LK’on PCB
330 Ohm –Orange, Orange, Brown, Gold
4.7K –Yellow, Violet, Red, Gold
10K –Brown, Black, Orange, Gold
22K –Red, Red, Orange, Gold
100K –Brown, Black, Yellow, Gold
NOTE: Many instructional videos including how to solder the printed circuit board (PCB) and the
associated components properly can be found at www.colmac.ie
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Step 2: Solder in the capacitors
Capacitors are devices that store electricity. Their size is measured in Farads, usually a small
fraction of a Farad such as a micro Farad (µF) or nano Farad (nF).
Solder the ceramic capacitors in their correct places either way around as they don’t have a + or -.
These capacitors are used primarily to reduce
electrical noise generated by the motors when
they are running. This electrical noise can
interfere with the operation of the E18
microcontroller.
As such, C3 and C4 are connected directly across the motor output connections Q6/7 and Q4/5.
Note that C5 shown in red is not required for this project.
Solder the electrolytic capacitor in its correct place. It has polarity i.e. a positive and negative.
The negative (-) leg is beside the grey stripe (marked with a minus sign) as shown below.
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Step 3: Solder in the diode
Diodes allow electricity to travel in one direction only.
Solder the diode in its correct place - it has polarity i.e. a positive and negative. The negative (-) leg
is beside the grey band as shown below.
Step 4: Solder the transistor, the reset switch and the USB jack
The transistor operates as an automatic switch.
The USB jack allows the microcontroller to connect to your computer.
The reset switch restarts the program from the beginning.
Grey band on negative side
Flat side
USB
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Step 5: Solder the status LED and chip sockets
Insert the green status LED as shown below –flat side is negative.
The chip sockets to hold the GENIE E18 microcontroller and L293D motor driver microchips should
be inserted as shown. The L293D chip allows the motor turn both clockwise and anti-clockwise
which gives forward/reverse and turning motion in the line follower robot.
Step 6: Solder the cable terminal blocks.
Insert the terminal blocks as shown –arrows indicate where flying lead cables will be inserted.
Notch
Flat side -
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NOTE: Soldering should be neat and uniform. Connections should not touch each other unless they
are supposed to as circled below.
Step 7: Insert E18 and L293D microchips
Try to handle the chip legs as little as possible but ensure that all legs are properly inserted into
their socket.
L293D
E18
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