The Versabot Manual

July 2009
Index

1. Getting Started
1.1 How this manual works
1.2 Breaking out your pieces

2. The Components
2.1 The Motherboard
2.2 The Modules
2.3 The Microbric ‘Brics’
2.4 Connecting the Batteries
2.5 Joining Modules to your Motherboard using the Brics
2.6 The Download Adapter

3. Programming the Microcontroller on your Motherboard

3.1 Installing the software
3.2 Pin Numbers
3.3 Making a LED flash
3.4 Adding a slide switch
3.5 Adding a buzzer
3.6 The push button
3.7 The motor – forwards/backward
3.8 Using bump sensors
3.9 The infrared receiver

4. Building your Bump Robot

4.1 What will it do?
4.2 Putting it together
4.3 Downloading the program to drive your bump robot
4.4 The code

5. Building your Remote Control Robot

5.1 What will it do?
5.2 Putting it together
5.3 Preparing the Remote Control
5.4 Downloading the program
5.5 The code

6. What Now?
6.1 Cleaning up the edges
6.2 Variations
6.3 Go online
1. Getting Started

Finally! An electronics set that is really easy to build without sacrificing functionality! Welcome to
Versabot, the first solderless construction set made for electronics enthusiasts.

1.1 How this manual works

This manual will take you through the various components that you have received in your kit and how
to join them together. It will describe how to use your computer to program the individual parts of your
project. You will then be shown how to put a basic Bump Robot together, and how to download a
program to drive it and, finally, you will see a diagram of a completed Infrared controlled robot for you
to build, and download the code to drive it. In addition, you can go online to view Frequently Asked
Questions, New Possibilities for construction and New Code for programming as well as finding out
the latest news in Versabot electronics.

If you follow the manual through from start to finish, you will learn everything you need to know to
create the robots we have given you, as well as the knowledge and skills needed to build and program
unique robots of your own. Additional information about programming the PICAXE microcontroller
which acts as the 'brains' of your Versabot is included in the PICAXE Manuals accessible through the
Programming Editor and AXEpad Help menus.

1.2 Breaking out your pieces

Your kit comes with a range of pieces, shown below.
A number of your pieces will have arrived within PCBs (printed circuit
boards). You need to remove these pieces before you can start building
your robot. Most pieces can be pushed out with your thumbs, but if you
are having difficulties, use the end of your screwdriver to gently lever
them out.
2. The Components
2.1 The Motherboard
The Motherboard contains the Labelled picture of
the Motherboard
'brains' of your robot. On it you will
(label parts listed
find a PICAXE-28X2 chip, a 9-way to the left)
download connector for
programming your micro-controller,
an on/off slide switch, Pins (edge
contacts), a Power LED, and a
variety of components and
integrated circuits needed to
connect the circuits electronically
and mechanically.

2.2 The Modules

Along with your motherboard you have received a range of little circuit boards that hold
electromechanical devices. Each of these has a different function and when joined to the
motherboard at the pins, you can program them to perform their functions.
The modules consist of:

LED module This module contains an LED (light emitting diode) and the
circuitry to drive it. A LED is a tiny light, used, amongst other
things, to show that an electronic device is turned on.

Slide Switch This module contains a small switch and the circuitry to drive
module it. A switch allows us to turn an electronic device on, or
‘switch’ between two electronic functions.

Buzzer This module contains a Buzzer and the circuitry to drive it.
module The buzzer is able to make sounds and even play simple
tunes.

Button This module contains a small push Button and the circuitry to
module drive it. It can be used to start or stop an electronic function.

Motor module This module contains a small Motor and the circuitry to drive
it. The motor can be used to drive wheels forwards and
backwards.

Bump Sensor This module contains a Bump Sensor and the circuitry to
module drive it. A bump sensor can detect when it touches
something, such as bumping into an object.

Infrared This module contains an Infrared Receiver and the circuitry

Receiver to drive it. An infrared receiver can pick up a signal sent
module using infrared light from a remote control device.
2.3 The Microbric ‘Brics’
Microbric ‘Brics’ are tiny building blocks which can be used to hold the motherboard and modules
together. These tiny black pieces fit into holes along the edge of the motherboard and the modules
(and other parts) and, when screws are added, complete the circuit. You will need to assemble your
Brics before you can use them. To do this, fit 3 of the tiny nuts into each bric.

You can then use the Brics to attach the various modules (and other pieces) to the motherboard.
When connecting modules to the motherboard you need to make sure of a few things:
1. Make sure that the little red dot on the
edge of the module lines up exactly with
the little red dots on the edge of the
Motherboard (at the pins).
2. Make sure that you use all 3 screws and
do them up firmly (but not too tight).
3. Make sure that the Bric is the right way
around. It will only fit one way – you do
not need to force pieces together!

2.4 Connecting the Batteries

The motherboard is powered by batteries. You have been provided with four counter sunk screws that
are different to all of the others (they have a flat, instead of a rounded, head), and 4 nuts. Use these
to attach the holder to the underside of the motherboard, making sure that the gold battery contact
pads are aligned with the slots in the blue battery mounts and the wires from the battery holders. (See
the diagram below). The kit requires 6 AAA batteries. Put these in before flicking the switch to power
up your motherboard. Once it is turned on, check that the tiny red power LED is lit up – this will
indicate that you have put it together correctly. If it doesn’t light up, check that your batteries are all in
the right way and that they are pushed in firmly before rechecking your assembly.
2.5 Joining Modules to your Motherboard using the Brics
The modules are joined to the motherboard using Brics. You connect each module at a Pin. The pins
are written around the outside edge of the motherboard as P0, P1, P2 etc.

Let’s try connecting a module:

1. Find a LED module, from your module collection.
2. Line up the red dot on your LED module with the red dot on the Motherboard at P0 (Pin 0).
3. Now fit a Microbric into the holes on the edge of your LED module
NOTE: The tiny pins on the Bric fit into the holes
if you put the Bric in the wrong way, the bric will sit crooked, i.e.

However, if you turn it up the other way it will sit straight. i.e.

4. Fit the Bric into the holes at P0 on the motherboard.

5. Now screw in three screws firmly to complete the connection.

If you’ve done it correctly, your Module and Motherboard should look like this:

2.6 The Download Adapter

Your Versabot is provided with a 9-way to 3.5mm Jack socket adapter for downloading. If you are
using an AXE026 or AXE027 PICAXE download cable, or any PICAXE download cable which has a
3.5mm Jack plug, you will need to insert the 9-way to 3.5mm Jack adapter into the 9-way connector
on your motherboard. The download cable then plugs into the 3.5mm socket. The adapter board can
be left connected to your motherboard.

If using a CAB010 9 way M-F serial download cable this can be connected directly to the motherboard
download connector.
3. Programming the Microcontroller on your Motherboard
Your motherboard is fitted with a PICAXE-28X2 microcontroller that can hold a range of instructions to
drive various electronic components. The sets of instructions are called programs and writing the
instructions is called programming.

3.1 Installing the software

Programming computers or microcontrollers is done using programming languages. Computers which
are electronic can only understand the simplest of languages which is written in binary, that is 0s and
1s (or an electrical ON or OFF). As you can imagine, programming a computer entirely in 0s and 1s
would be very, very slow and tedious. So, higher level programming languages have been developed
to make this easier. There are hundreds of languages available, however our Microcontroller uses a
special programming language which has been written for it based on the BASIC programming
language. BASIC is easy to learn and remember.

To write programs, write programs, and to download them into the PICAXE microcontroller,
you need to install either the PICAXE Programming Editor or the cross-platform AXEpad
program.

3.2 Pin Numbers

The PICAXE motherboard has its connection pins labelled P0 to P15 but the PICAXE-28X2 uses a
different 'software terminology' than the 'hardware terminology'; a hardware connection to P2 is a
software connection to B.2, a hardware connection to P14 is a software connection to C.6 and so
forth.

This situation is very common in computer engineering where a general purpose programmable chip
is used with specific hardware and is very easy to deal with. All that is required is a table which maps
'hardware terminology' to 'software terminology' and you can go on using the hardware descriptions,
for example pin 1 (P1), which makes sense to you and the controlling software will understand what
you mean.

This table is implemented by using symbol commands and the complete set of pin mappings is as
follows:

symbol P0 = B.0 symbol P8 = C.0

symbol P1 = B.1 symbol P9 = C.1
symbol P2 = B.2 symbol P10 = C.2
symbol P3 = B.3 symbol P11 = C.3
symbol P4 = B.4 symbol P12 = C.4
symbol P5 = B.5 symbol P13 = C.5
symbol P6 = B.6 symbol P14 = C.6
symbol P7 = B.7 symbol P15 = C.7

There is another set of mappings for when the pins are used as inputs:

symbol IN0 = pinB.0 symbol IN8 = pinC.0

symbol IN1 = pinB.1 symbol IN9 = pinC.1
symbol IN2 = pinB.2 symbol IN10 = pinC.2
symbol IN3 = pinB.3 symbol IN11 = pinC.3
symbol IN4 = pinB.4 symbol IN12 = pinC.4
symbol IN5 = pinB.5 symbol IN13 = pinC.5
symbol IN6 = pinB.6 symbol IN14 = pinC.6
symbol IN7 = pinB.7 symbol IN15 = pinC.7

The details of the table and the mappings is not really important unless you want to get more deeply
involved in PICAXE programming generally. All you need to do is include the revelevent Symbol for
each pin your program uses at the top of the program. You can of course include the complete table of
Symbol definitions if you wish.

A complete list of PICAXE-28X2 mappings is included as program Picaxe28x2.bas on the CD-ROM

which may be cut and pasted into your programs as required.
3.3 Making an LED flash
Now let’s write our first program and then download it to your microcontroller.
1. Earlier we connected a LED module to pin 0 (P0) of the motherboard. If you haven’t done this
step, go to 2.5 Joining Modules to your Motherboard using Microbrics and follow the
instructions there.
2. Open the PICAXE Programming Editor or AXEpad program.
3. When the Programming Editor or AXEpad opens you will be presented with a configuration
screen. If such a screen does not appear use the View/Option menu to display it.
4. Select the Mode panel and select the 20X2 option to match your motherboard PICAXE-28X2
microcontroller.
5. Select the Mode panel and select the serial port your download cable is connected to.
6. When you have finished click the OK button. You will be returned to the editing screen where
you can enter your program for the Versabot.
7. A good thing to do before writing code for a program is to draw a flow chart of how the
program will work. Here is an example of a flow chart that shows what our program will do:

START

Turn on LED

Keep on for
200
milliseconds

Turn off LED

Keep off for

200
milliseconds

8. Write the following program into the text window.

NOTE: It is important to type in exactly what is shown, because programming languages use
very specific code called syntax. If the syntax is incorrect, the software, and later the
hardware which is getting an interpreted version in binary, will not be able to read it. Note that
the space indents and Tab key alignments are used to make your program easier to read.
Writing after a single-quotes are comments and don’t affect the compiling or how the program
operates.
symbol P0 = B.0 ' Define Output P0

do ' Do the following ...

high P0 ' Set P0 high (5V)
pause 200 ' Keep P0 high for 200ms
low P0 ' Set P0 low (0V)
pause 200 ' Keep P0 low for 200ms
loop ' Repeat this loop forever

Some things to note about the program above:

• Notice that we have used space characters to indent parts of the program and the Tab
key to align things. This isn’t necessary, but makes it easier to read.
 • Notice that the parts in grey after the single-quotes are descriptions of what the program
is doing. These also aren’t necessary, but help you to understand what your program is
doing, and to remember what it was doing when you come back to it in a year’s time (so
spelling mistakes don’t matter in here).
• Note that we are using P0 which is an output so specified P0 in the High and Low
commands, and provided the symbol definition required for P0 at the top of the program.
• We used a do / loop to keep the program ‘running round in circles’. The program will
continually repeat the commands within that loop until the Versabot is turned off or a new
program is downloaded to it.
9. Save your program to disk using the File/Save menu option and save your file as
LEDprogram.bas.
10. It is very important to save your programs. Although the Versabot will remember what program
was last downloaded to it, there is no way to read the program out of the Versabot later. If you
want to have a copy of your program you must save it to disk.
11. Make sure the download cable is securely connected to your computer and to the download
connector on your Versabot motherboard. Also, make sure your Versabot motherboard has
batteries and is switched on
12. Press the F4 key ( or use the PICAXE/Check Syntax menu option ) to check the syntax of
your program. If you have made any mistakes in typing your program the compiler will indicate
what they are’ click OK and correct any mistakes. When you have the program correct the
compiler will report “Syntax check successful!” and give an indication of how big your program
is, how much space is required to store that program.
13. Press the F5 key ( or use the PICAXE/Program menu option ) to download your program into
the PICAXE on your Versabot motherboard. A display screen will pop-up to show progress of
the program being downloaded.
14. Once the downloading has completed, you should see the light at pin 0 start to flash. You can
disconnect the serial cable and it will keep going. The program stays permanently in the
PICAXE memory, so you can turn the flashing LED on and off using the motherboard power
switch.
3.4 Adding a Slide Switch
1. Now let’s attach a slide switch and use it to control the speed of flashes on the LED.
2. Attach the Slide Switch module to P0 on the edge of your Micobric motherboard next to the
LED module (note the 0 and 1 written in gold on the module).

3. Again, let’s draw a flow diagram before we write the program. Here is one for the program we
will write.

START

No
Is switch
on?

Yes

Turn on LED

Keep on for
200
milliseconds

Turn off LED

Keep off for

200
milliseconds

Turn on LED

Keep on for
2000
milliseconds

Turn off LED

Keep off for

2000
milliseconds
4. Now change the program so that it is the same as below. It is just the same as above but
modified with an if / else / end if statement (to set up two possible paths for the program to
follow):
symbol P0 = B.0 ' Define Output P0
symbol IN1 = pinB.1 ' Define Input P1

do ' Do the following ...

if IN1 = 1 then ' When the slide switch is a 1 ...
high P0 ' Set P0 high (5V)
pause 200 ' Keep P0 high for 200ms
low P0 ' Set P0 low (0V)
pause 200 ' Keep P0 low for 200ms
else ' Otherwise ( slide switch is a 0 ) ...
high P0 ' Set P0 high (5V)
pause 2000 ' Keep P0 high for 2000ms (2s)
low P0 ' Set P0 low (0V)
pause 2000 ' Keep P0 low for 2000ms (2s)
end if
loop ' Repeat this loop forever

Some things to note about the program above:

• The module at Pin 1 accepts input from the user and so it is referred to as IN1. This tells
the microcontroller to expect input at this pin. We also add the symbol definition for IN1 at
the top of the program.
5. Save your program as SlideSwitchprogram.bas
6. Press the F5 key ( or use the PICAXE/Program menu option ) to download your program into
the PICAXE on your Versabot motherboard. A Syntax Check is automatically performed
before downloading so it isn’t necessary to press the F4 key ( or use the PICAXE/Syntax
Check menu option ) before starting a download, but you can press F4 to check the syntax
before downloading if you wish.
7. Once the downloading has completed you can switch the slide switch back and forth to see
the difference in the LED flashing speeds.
8. The program downloaded completely replaces the previous program in the Versabot PICAXE
and it will be remembered even while the Versabot is turned off. The Versabot PICAXE always
remembers the last program downloaded to it, and only the last program downloaded.
3.5 Adding a buzzer
Now lets look at how the buzzer works. We will use the sound command to control the buzzer.

1. Connect the buzzer module to P2.

2. Now lets write a program that plays two different “tunes”

depending on whether the slide switch is at 0 or 1. The flow Start
diagram will look like this:

Is the No
switch
1?
Yes

While the switch is

on 1, play tune 1

If the switch is
changed to 0

While the switch is

0, play tune 2

3. To program the buzzer, we will use the sound command. Let’s have a look at how the sound
command works. The sound command takes the general form:

SOUND pin,( note1\duration1, note2\duration2 ……noteX\durationX )

pin: this is the pin number that the buzzer is connected to (i.e. P2)
note: is a number between 1 and 127 that specifies the frequency of the note.
duration: this is a value between 1 and 65535 telling the buzzer how long to stay on the given
note for.

You can put together a series of notes to make a tune by specifying note length and note
frequency.

4. Start the Programming Editor or AXEpad, or start a new program by using the
File/New/Basic Program menu option.
 5. Now, type the following into the text window:
symbol IN1 = pinB.1 ' Define Input P1
symbol P2 = B.2 ' Define Output P2

do ‘ Do the following ...

do while IN1 = 1 ' While the slide switch is a 1 ...

sound P2, (100,50,110,50) ' Play two high tones
pause 500 ' And delay between tones
loop ' Repeat this loop while the slide switch is 1

do while IN1 = 0 ' While the slide switch is a 0 ...

sound P2, (50,50,60,50) ' Play two low tones
pause 500 ' And delay between tones
loop ' Repeat this loop while the slide switch is 0

loop ' Repeat forever

Some things to note about the program above:

• The do while command sets up a condition that while the switch is in a certain position (i.e the
1 position) a program sequence will follow. This will keep looping and will test the condition
each time before it proceeds. As soon as that condition changes (i.e. The switch is moved to
the 0 position) it will break out of the loop and continue through the code further down the
program.
• Each do command has a corresponding loop command to show where the loop ends.
Indentation is used so each do command lines up with its corresponding loop.
• Each sound command is just a two note tune in this case; more notes can be added as
required.

6. Save your program as Buzzerprogram.bas.

7. Press the F5 key ( or use the PICAXE/Program menu option ) to download your program into the
PICAXE on your Versabot motherboard.
8. Once the downloading has completed you can switch the slide switch back and forth to play the
two different tunes.
9. Now we can modify the above program to include a LED and a buzzer and use the switch to
interchange between the two.
 START

No
Is switch
on?

Yes

Turn on LED

Keep on for
200
milliseconds

Turn off LED

Keep off for

200
milliseconds

Play buzzer
tune

symbol P0 = B.0 ' Define Output P0

symbol IN1 = pinB.1 ' Define Input P1
symbol P2 = B.2 ' Define Output P2

do ' Do the following ...

if IN1 = 1 then ' When the slide switch is a 1 ...
high P0 ' Set P0 high (5V)
pause 200 ' Keep P0 high for 200ms
low P0 ' Set P0 low (0V)
pause 200 ' Keep P0 low for 200ms
else ' Otherwise ( slide switch is a 0 ) ...
sound P2, (100,50,110,50) ' Play two high tones
pause 500 ' And delay between tones
end if
loop ' Repeat this loop forever
10. Save your program as SlideSwitchprogram2.bas.
11. Press the F5 key to download your program into the PICAXE on your Versabot motherboard
12. When the slide switch is equal to 1, the LED will start to flash. If the slide switch equals 0, the
buzzer will start playing the two-tone tune.
3.6 The Push Button
This section will give you an example of the use of a push button. Push buttons are extremely useful
for a range of things and so the Button programming code has quite a number of parameters (parts to
the code command that can vary).

1. Attach the Push Button module to P3 on the edge of the motherboard.

2. Start the Programming Editor or AXEpad, or start a new program by using the
File/New/Basic Program menu option.
3. Now, type the following into the text window:
symbol P0 = B.0 ' Define Output P0
symbol IN3 = pinB.3 ' Define Input P3

symbol PushButton = IN3 ' Define the PushButton input

do ' Do the following ...

low P0 ' Initialise LED off
if PushButton = 1 then ' When button pushed ..
gosub LightLED ' Call the LightLED subroutine
end if
loop ' Repeat forever

LightLED:
high P0 ' Turn P0 LED on
pause 1000 ' Leave on for 1000ms (1s)
return ' And return from subroutine

Some things to note about the program above:

• This time we have defined a variable called PushButton at the very beginning of the program.
It is called a ‘variable’ because the value can vary according to input from the user. Note that
the value for PushButton will be input at Pin 3 (IN3).
• We have added a subroutine to the program and given it the label LightLED. The name of
the label should indicate what the function does. Subroutines are used to break up a long
program into smaller ‘sub-programs’.
• Subroutines are called by using the gosub command and a subroutine returns control to the
line following the gosub command by using a return command. It is very important to add
the return command at the end of each subroutine.
4. Save your program as PushButton.bas.
5. Press the F5 key to download your program into the PICAXE on your Versabot motherboard.
6. Press the button at Pin 3 to turn the LED on and off.
3.7 The Motor

1. Attach the Motor module to P4 on the edge of the motherboard. Connect one of your wheels
to the motor axle.

2. Before writing the program below, let’s have a look at the serout and pulsout commands in
BASIC. The serout command allows you to specify such things as the direction and speed of
the motor. The pulsout sends a tiny pulse to brake the motor.
They are written in the following general formats:

SEROUT pin, baudmode, ( output data )

pin: this is the pin number the motor is connected to.

baudmode: is a variable or constant that specifies serial timing and configuration – in our
case we use T2400 as the baud rate.
output data: is information that effects the direction and speed of our motor – in our case the
data includes direction (i.e. clockwise or anticlockwise) and speed which ranges from 0 to 255.
PULSOUT pin, time
pin: this is the pin number the motor is connected to.
time: the duration of the pulse, measured in milliseconds.

3. Start the Programming Editor or AXEpad, or start a new program by using the
File/New/Basic Program menu option and then type in the following program:

symbol P4 = B.4 ' Define Output P4

high P4 ' Set the motor line high

pause 50 ' Wait for motor module to be ready
do ' Do the following ...
serout P4, T2400, ("C",150) ' Drive motor clockwise at speed 150
pause 5000 ' Continue for 5000ms (5s)
pulsout P4, 6 ' Send a 6ms pulse to brake the motor
serout P4, T2400, ("A",150) ' Drive motor anti-clockwise at speed 150
pause 5000 ' Continue for 5000ms (5s)
pulsout P4, 6 ' Send a 6ms pulse to brake the motor
loop ' Repeat forever
4. Save your program as Motorprogram.bas.
5. Press the F5 key to download your program into the PICAXE on your Versabot motherboard.
6. The motor should turn one way, stop briefly, then turn the other way.
7. Turn the motherboard off to stop the motor.
3.8 The Bump Sensor
Before using the Bump Sensor module, you will need to assemble the bump sensor itself.

1. Attach the Bump Sensor module to P5 on the edge of the motherboard.

2. Keep the assembled Versabot wheels off the ground or it may ‘run away’ with the download
cable attached when you download your program to it.

3. Start the Programming Editor or AXEpad, or start a new program by using the
File/New/Basic Program menu option.
4. Now, type the following into the text window:
symbol P0 = B.0 ' Define Output P0
symbol P4 = B.4 ' Define Output P4
symbol IN5 = pinB.5 ' Define Input P5

high P4 ' Set the motor line high

pause 50 ' Wait for motor module to be ready
do ' Do the following ...
low P0 ' Initialise the LED off
do ' Go forwards ...
serout P4, T2400, ("C",150) ' Drive motor clockwise at speed 150
pause 100 ' Continue for 100ms
loop until IN5 = 1 ' Until the bump sensor is triggered
high P0 ' Turn LED on
pulsout P4, 6 ' Send a 6ms pulse to brake the motor
serout P4, T2400, ("A",150) ' Drive motor anti-clockwise at speed 150
pause 2000 ' Continue for 2000ms (2s)
pulsout P4, 6 ' Send a 6ms pulse to brake the motor
loop ' Repeat forever
5. Note the use of IN5 instead of P5 because we are getting input from a user.
6. Save your program as BumpSensorprogram.bas.
7. Press the F5 key to download your program into the PICAXE on your Versabot motherboard.
8. The motor should start turning the wheel clockwise. When the bumper is pushed, the LED
should light and the wheel should change direction to anticlockwise.
3.9 The Infrared Receiver
The Infrared Receiver module allows you to simply control your Versabot using a TV-like remote
control. The TV remote control, if required, is available separately as part TVR010.

1. Attach the Infrared Receiver module to Pin 6 on the Versabot motherboard.

2. In order to use the remote control with the microcontroller, you will need to follow a sequence
of steps to preset the remote to work with the microcontroller.
a. Put two AAA batteries into the remote control unit.
b. Simultaneously hold down the S button (in the middle of the arrows) and the B button
on the remote (a red light will go on in the top left hand corner of the remote.)
c. Press the number sequence 0 1 3 on the remote buttons.
d. Press the red power button on the remote.
e. The remote is now configured to work with your microcontroller.

Note that buttons A, C, D, E, F and G are for setting the remote control into different modes which
are not required for this project. Avoid pressing these buttons as this will inadvertently set your
remote into another mode. You can always return to the ‘B’ mode by pressing the B button.

3. Start the Programming Editor or AXEpad, or start a new program by using the
File/New/Basic Program menu option.

4. In this program you will be using the infrain command. This is a command that tells the
microcontroller to wait for a remote control signal.

'**Variables**
symbol keyPressed = w0
symbol timeout = w1

'**PICAXE motherboard pin definitions**

symbol P0 = B.0
symbol P2 = B.2
symbol P4 = B.4
symbol P6 = B.6

'**PICAXE motherboard input definitions**

symbol IN6 = pinB.6

'**IR Remote Keys**

symbol KEY_UP = 16
symbol KEY_DOWN = 17
symbol KEY_LEFT = 19
symbol KEY_RIGHT = 18

high P4 ' Initialise motor

do
gosub ReadIrCommand ' Read the IR command
gosub ObeyIrCommand ' Obey the IR command
loop
 ReadIrCommand:
irin P6, keyPressed ' Read an IR comand
return

ObeyIrCommand:
select case keyPressed
case KEY_UP : gosub GoForward ' When up arrow, clockwise
case KEY_DOWN : gosub GoBackwards ' When down arrow, anticlockwise
case KEY_RIGHT : gosub LightLED ' When right arrow then light LED
case KEY_LEFT : gosub PlayTones ' When left arrow then play tones
end select
return

GoForward:
serout P4,T2400,("C",255) ' Run motor forward
gosub WaitWhileKeyHeld ' Wait for key release
pulsout P4,6 ' Stop Motor
return

GoBackwards:
serout P4,T2400,("A",255) ' Run motor backwards
gosub WaitWhileKeyHeld ' Wait for key release
pulsout P4,6 ' Stop Motor
return

LightLED:
high P0 ' Turn LED on
pause 1000 ' Keep on for 1000ms (1s)
low P0 ' Turn LED off
return

PlayTones:
sound P2,(50,50,60,50) ' Play two tones
return

WaitWhileKeyHeld: ' Wait until IR key released

timeout = 0
do
inc timeout
if IN6 = 0 then
timeout = 0
end if
pause 1
loop until timeout > 25
return
5. Save your program as IRProgram.bas
6. Press the F5 key to download your program into the PICAXE on your Versabot motherboard.
7. Disconnect the download cable and place your Versabot on the ground.
8. Press the left, right, up and down buttons of your remote control to instruct your robot to do
things; move forwards and backwards, play a tune and flash its LED
 Remote Control Button Values

Button Value
On/Off Power 21
1 0
2 1
3 2
4 3
5 4
6 5
7 6
8 7
9 8
0 9
/\ Up 16
\/ Down 17
< Left 19
> Right 18
| Vertical Bar 96
/\ Tent 54
+ Vertical Cross 37
X Diagonal Cross 20
- Minus 98
+ Plus 11

A list of remote control key codes definitions is included as program IrKeys.bas on the CD-ROM
which may be cut and pasted into your programs as required.

symbol KEY_POWER = 21
symbol KEY_1 =0
symbol KEY_2 =1
symbol KEY_3 =2
symbol KEY_4 =3
symbol KEY_5 =4
symbol KEY_6 =5
symbol KEY_7 =6
symbol KEY_8 =7
symbol KEY_9 =8
symbol KEY_0 =9
symbol KEY_UP = 16
symbol KEY_DOWN = 17
symbol KEY_LEFT = 19
symbol KEY_RIGHT = 18
symbol KEY_BAR = 96
symbol KEY_TENT = 54
symbol KEY_VERT_CROSS = 37
symbol KEY_DIAG_CROSS = 20
symbol KEY_MINUS = 98
symbol KEY_PLUS = 11
4. Building your Bump Robot
4.1 What will it do?
The Bump robot will drive in a straight line until it hits an
obstacle. If the ‘bump sensors’ meet an obstacle, such as a
wall, the robot will stop, reverse and try a new direction. You
will press the button to start it moving.

4.2 Putting it together

Disconnect the modules from the motherboard but leave the battery holders in place. Now follow the
step by step illustrations below to build your bump robot.

Step 01

Step 02
Step 03

Step 04

Step 05
Step 06

Step 07

Step 08
Step 09

Step 10

Step 11
Step 12

Step 13
4.3 Downloading the program to drive your bump robot
Once your bump robot is built:
1. Start the Programming Editor or AXEpad and open the file BumpRobot.bas from your
CD-ROM ( File/Open).
2. Save the program (File/Save As…) to a location on you hard drive.
3. Connect the download cable to your motherboard.
4. Press the F5 key to download your program into the PICAXE on your Versabot
motherboard.
5. Disconnect the download cable and place your Versabot on the ground.
6. Press the button on the Button Module to start your Bump Robot.

4.4 The Code

We have included the code here so that you can investigate the program used:

'**Variables**
symbol temp = w0

'**PICAXE motherboard output pin definitions**

symbol P0 = B.0
symbol P1 = B.1
symbol P11 = C.3
symbol P12 = C.4

'**PICAXE motherboard input pin definitions**

symbol IN6 = pinB.6
Symbol IN13 = pinC.5
symbol IN15 = pinC.7

'**Outputs**
symbol LeftLED = P0
symbol RightLED = P12
symbol RightMotor = P11
symbol LeftMotor = P1

'**Inputs**
symbol PushButton = IN6
symbol LeftBumper = IN15
symbol RightBumper = IN13

'Initialise Motor outputs

StartOfProgram:
high RightMotor
high LeftMotor
pause 50

StopRobot:

gosub StopMotors ' Call StopMotors

low LeftLED ' Turn LeftLED off
low RightLED ' Turn RightLED off
pause 250 ' Pause for 250ms

do ' Ensure no button pushed

loop until PushButton = 0

do ' Wait until button pushed

loop until PushButton = 1
Main:
toggle LeftLED ' Swap the state of Left LED
toggle RightLED ' Swap the state of Right LED
gosub GoForward ' Call "GoForward"
pause 200 ' Pause for 200ms
if LeftBumper = 1 then BackwardTurnRight ' If right bumper sensor
' BackwardTurnRight
if RightBumper = 1 then BackwardTurnLeft ' If the right bumper sensor
' BackwardTurnLeft
if PushButton = 1 then StopRobot ' If Push Button is pressed
' StopRobot
goto Main ' Loop around to Main

BackwardTurnRight:
gosub StopMotors ' Call StopMotors
gosub GoBackwards ' Call GoBackwards
gosub TurnRight ' Call TurnRight
goto Main ' Loop around to Main

BackwardTurnLeft:
gosub StopMotors ' Call StopMotors
gosub GoBackwards ' Call GoBackwards
gosub TurnLeft ' Call TurnLeft
goto Main ' Loop around to Main

GoForward:
serout LeftMotor,T2400,("A",150) ' Drive motor Anticlockwise
serout RightMotor,T2400,("C",150) ' Drive motor Clockwise
return

GoBackwards:
pause 50
serout LeftMotor,T2400,("C",150) ' Drive motor Clockwise
serout RightMotor,T2400,("A",150) ' Drive motor Anticlockwise
for temp = 1 to 25
pause 7
if PushButton = 1 then StopRobot ' If Push Button is pressed
' StopRobot
next
gosub StopMotors
pause 50
return

TurnRight:
serout LeftMotor,T2400,("A",150) ' Drive motor Anticlockwise
serout RightMotor,T2400,("A",150) ' Drive motor Anticlockwise
for temp = 1 to 25
pause 15
if PushButton = 1 then StopRobot ' If Push Button is pressed
' StopRobot
next
gosub StopMotors
pause 50
return

TurnLeft:
serout LeftMotor,T2400,("C",150) ' Drive motor Clockwise
serout RightMotor,T2400,("C",150) ' Drive motor Clockwise
 for temp = 1 to 25
pause 15
if PushButton = 1 then StopRobot ' If Push Button is pressed
' StopRobot
next
gosub StopMotors
pause 50
return

StopMotors:
pulsout LeftMotor,6 ' Brake Left Motor
pulsout RightMotor,6 ' Brake Right Motor
return
5. Building your Infrared Versabot Robot
5.1 What will it do?
Your infrared Versabot can be driven using your remote control.

5.2 Putting it together

Use the following diagram to see how the Versabot goes together. Having built the “Bump Robot” you
should have no difficulties now building your Versabot.

5.3 Preparing the Remote Control

In order for the Versabot microcontroller to receive signals from the remote control unit that has come
with your kit, you will need to work through a preset routine.
1. Put two AAA batteries into the remote control.
2. Simultaneously press the S button (in the middle of the arrows) and the B button (at the top of
the remote) until the little red light goes on in the top left hand corner.
3. Now type in the numbers 0 1 3
4. Press the red power button
5. The remote is now ready to be used with your robot.

Note that buttons A, C, D, E, F and G are for setting the remote control into different modes which are
not required for this project. Avoid pressing these buttons as this will inadvertently set your remote into
another mode. You can always return to the ‘B’ mode by pressing the B button.

5.4 Downloading the program

Once your Infrared Versabot robot is built:
1. Open Start the Programming Editor or AXEpad and open the file
IRControlledRobot.bas from your CD-ROM ( File/Open).
2. Save the program (File/Save As…) to a location on you hard drive.
3. Connect the download cable to your motherboard.
4. Press the F5 key to download your program into the PICAXE on your Microbric
motherboard.
5. Disconnect the download cable and place your Versabot on the ground.
6. Press the direction arrows on your remote control to drive your Versabot.
5.5 The Code

'**Variables**
symbol keyPressed = w0
symbol motorSpeed = w1
symbol timeout = w2

'**PICAXE motherboard pin definitions**

symbol P6 = B.6
symbol P13 = C.5
symbol P14 = C.6
symbol P15 = C.7

'**PICAXE motherboard input definitions**

symbol IN14 = pinC.6

'**Pins**
symbol LED_PIN = P6
symbol LeftMotor = P13
symbol RightMotor = P15
symbol IR_PIN = P14

'**Inputs**
symbol IR_SIGNAL = IN14

'**IR Remote Keys**

symbol KEY_UP = 16
symbol KEY_DOWN = 17
symbol KEY_LEFT = 19
symbol KEY_RIGHT = 18
symbol KEY_POWER = 21
symbol KEY_0 =9
symbol KEY_1 =0
symbol KEY_2 =1
symbol KEY_3 =2
symbol KEY_4 =3
symbol KEY_5 =4
symbol KEY_6 =5
symbol KEY_7 =6
symbol KEY_8 =7
symbol KEY_9 =8

'**Initialise Motor Outputs**

High LeftMotor
High RightMotor
motorSpeed = 150 ' Initial motor speed
pause 500

'**Main program Loop**

do
low LED_Pin ' No IR command
Gosub ReadIrCommand ' Read the IR command
High LED_Pin ' Set LED when obeying command
Gosub ObeyIrCommand ' Obey the IR command
loop

ReadIrCommand:
IrIn IR_PIN, keyPressed ' Read an IR command
return
ObeyIrCommand:
select case keyPressed
case KEY_UP : gosub GoForward
case KEY_DOWN : gosub GoBackwards
case KEY_LEFT : gosub TurnLeft
case KEY_RIGHT : gosub TurnRight
case KEY_POWER : gosub StopMotors
case KEY_0 : motorSpeed = 70
case KEY_1 : motorSpeed = 90
case KEY_2 : motorSpeed = 110
case KEY_3 : motorSpeed = 130
case KEY_4 : motorSpeed = 150
case KEY_5 : motorSpeed = 170
case KEY_6 : motorSpeed = 190
case KEY_7 : motorSpeed = 210
case KEY_8 : motorSpeed = 230
case KEY_9 : motorSpeed = 255
else : return
end select
gosub WaitWhileKeyHeld
return

GoForward:
serout LeftMotor,T2400,("A",motorSpeed)
serout RightMotor,T2400,("C",motorSpeed)
return

GoBackwards:
serout LeftMotor,T2400,("C",motorSpeed)
serout RightMotor,T2400,("A",motorSpeed)
return

TurnLeft:
serout LeftMotor,T2400,("C",motorSpeed)
serout RightMotor,T2400,("C",motorSpeed)
return

TurnRight:
serout LeftMotor,T2400,("A",motorSpeed)
serout RightMotor,T2400,("A",motorSpeed)
return

StopMotors:
pulsout LeftMotor,6 ' Brake Left Motor
pulsout RightMotor,6 ' Brake Right Motor
return

WaitWhileKeyHeld: ' Wait until IR key released

timeout = 0
do
inc timeout
if IR_SIGNAL = 0 then
timeout = 0
end if
pause 1
loop until timeout > 25
return
6. What now?
6.1 More Programming Information
There is so much more to the PICAXE 28X2 than what has been covered here. For further details on
the PICAXE processors and programming language see the PICAXE Manuals accessible from the
Help menu options of the PICAXE Programming Editor and AXEpad.

6.2 Cleaning up the edges

You may find that the pieces that have been pushed out of the sheets have rough edges. Find a small
file (a metal nail file will do) and gently file the edges smooth to perfect your robots.

6.3 Variations
You now know enough about programming to make your own variations of the models provided.
Experiment with a range of robot designs and write or adapt the programs to drive your new robots.

6.4 Go Online
Want more? Go online to www.picaxe.com to find out the latest news in PICAXE
Robotics! Join an online forum. Find out the newest models and designs. Buy
additional pieces or replace missing ones. Check out the FAQs to troubleshoot
problems, or Contact the PICAXE team.