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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Step 8: Make flying lead connectors for LED, LDRs and motors
Use the coloured cable to make flying lead connectors as shown in the following pictures.
For the LED, cut approx. 170mm of each cable, braid together as shown and remove approx. 5mm
of insulation from the ends.
Shorten the legs of the LED as shown using snips/pliers etc. in order to minimise the chance of
them touching each other and creating a short circuit.
Braid the individual strands of the exposed cable in order to minimise stray cable strands touching
each other and solder the LED as shown. Take note of which cable is connected to the flat side of
the LED.
5mm
Twist/braid
strands together
Black connected
to flat side of LED

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For the LDRs, cut approx. 250mm of each cable, braid together as shown and remove approx. 5mm
of insulation from the ends as before.
As before, shorten the legs of both LDRs as shown to approx.
10mm using snips/pliers etc. in order to minimise the chance
of them touching each other and creating a short circuit.
Braid the individual strands of the exposed cable in order to minimise stray cable strands touching
each other and solder the LED as shown. Take note of
which cable is connected to the flat side of the LED.

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For the motors, cut approx. 150mm of each cable, braid together as shown and remove approx.
5mm of insulation from the ends.
Solder the flying leads to the motors as shown. Be careful with the motor connections as they are
quite delicate.
If possible use similar colour cables
in the positions as shown in order
to program in accordance with the
notes later.

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Step 9: Attach motors to chassis using sticky pads
The motors should be attached to the plastic chassis using two sticky pads on each as shown below.
The motor cables are then fed through the holes as shown.
The edge of the motors should be
positioned on the chassis as seen here.
Line up the edge of the
motor with the edge of
the chassis marked in red.

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Step 10: Attach battery pack/switch to chassis.
Attach 2 sticky pads to the battery pack on the switch side as shown.
Stick down the battery pack as seen below –try to centre on the chassis in order to keep it
balanced.
Feed the red (+V) and black (0V)
cables through the holes as shown.
Battery pack cable

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Step 11: Connect motor flying leads to the E18 PCB
Firstly attach two sticky pads to the bottom of the PCB in each of the approximate positions shown.
2 x sticky pads are used in each case in order to
accommodate the raised soldered joints and
ensure secure fit to the chassis.
Then insert the cable from each motor into the M3 and M4 connectors preferably in the same
manner as shown below in order to correspond with the programming later on. Do not worry
however if they are inserted differently as changes can easily be made to the programming.
Q4=Black
Q5=Yellow
Q6=Black
Q7=Yellow

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Step 12: Insert LED in chassis and connect to E18 PCB
Insert the line illumination LED into the front of the
chassis as shown and feed the flying lead through the
centre cable hole.
Route the LED flying lead through the hole beside the
PCB as shown.
Connect negative (-) cable (black in this case) to the
right side connection of output Q3 and the other cable
to the left side positive (+) connection.
NOTE: If the LED is connected the wrong way around it
will not be damaged but will simply not work.
Flat side = Negative (-)
__
+

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Step 13: Connect battery power leads to the E18 PCB
Connect the red (+V) and black (0V) cables to the relevant connectors as shown below. If the cables
are connected the wrong way around the E18 chip will heat up and may be damaged.
Step 14: Insert LDRs in chassis and connect to E18 PCB
Insert the two LDRs into the front of the chassis
as shown and feed the flying lead through the
cable holes.
NOTE: Ensure that the LDR legs do not touch
each other or the legs of the LED which would
result in a short circuit.
0V +V
A2
A0

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Route the cables through the remaining holes as shown and connect into the input terminals A0
and A2 as shown on page 8.
NOTE: Light Dependent Resistors (LDRs) do not have polarity (positive/negative) which means that
it does not matter how the cables are connected into the terminal blocks.
Finally, using the sticky pads, attach the E18 to the chassis in the position shown.
A2
A0

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Step 15: Attach the rubber bands to the wheels and the wheels to the motors.
The rubber bands are used to increase the grip of the wheels. When attached the wheels should
push fit on to the motor drive shaft.
Step 16: Assemble the rear spoiler and attach to chassis
The 5mm end of the support fits into
the spoiler.
The 3mm end of the support fits into
the chassis.
5mm
3mm
Support
Spoiler