P.S. Nair Tutorial Robotics with Boe-Bot and PBASIC .docx

P.S. Nair
Tutorial: Robotics with Boe-Bot and PBASIC
This tutorial introduces you to the PBASIC programming
language and the Boe-Bot
development board and robotics kit. PBASIC is used to program
the microcontroller that comes
with the Boe-Bot robotics kit, which is sold by Parallax. This
microcontroller is known as the
BASIC Stamp.
Please note that the objective of this tutorial is to help you get
started with PBASIC
programming and the Boe-Bot robotics kit. It is not intended to
be a complete reference.
Where to write your programs? The BASIC Stamp Editor
You need to write your PBASIC program using the BASIC
Stamp Editor software. This
software should already be installed on the computers in the
classroom. If you want to install the
software on your home PC or laptop, you can download the
latest version from the Parallax
website. The link for the download and install web-page for
BASIC Stamp Editor is
http://www.parallax.com/basicstampsoftware
BoeBot Development Board Details
The Boe-Bot development board that you will be using in this

class is the “Parallax Board of
Education - Rev D (USB)” and looks as shown below:
Fig. 1. Parallax Boe-Bot Development Board and its parts
http://www.parallax.com/basicstampsoftware
P.S. Nair
‘Board of Education – USB’ and click on the arrow that is
labeled as ‘NEXT’. You will be
taken to a page where you will be able to see the description of
the various parts of the
development board shown in Fig. 1. At the top of this page, you
should be able to locate several
icons. Move the cursor over the icons and when you find the
icon that says ‘Expand all’, click on
that icon. Read the information provided and bookmark the page
for later reference.
Connecting the Development Board to your Computer (PC)
1. Connect the battery holder (it holds 4 AA batteries) to the
part number 2 on the board
(see Fig. 1) using the cable attached to the battery holder.
2. Slide the power switch (part number 11 on the board) to the
position 1(middle
position).This will power up the board.
When you want to run the servo motors, the switch should be in
position 2

3. After you have connected the battery pack to the board, take
the USB cable and connect
the broad end of the cable to a USB drive on your computer.
Connect the narrow end to
part number 13 on the board (see Fig. 1).
Important (Please note): When you are done using the board,
please disconnect the USB
cable first before removing the power connection to the battery
pack.
4. Next, you need to test the connection between the board and
the computer. In order to do
this, click on the functional key F6 on your keyboard.
Alternatively, you can click on
connection has been properly
done, you will see the that the connection has been detected on
one of the COM ports of
the computer, similar to what is shown in Fig. 2 below (in this
figure, it is indicated that
COM5 is where the connection was detected and the device
identified was BASIC Stamp
2).
Fig. 2 Example result of a correct connection check
P.S. Nair

Writing your first PBASIC Program
1. In the Debug Terminal (main window of Basic Stamp Editor),
type the following
program:
' First PBASIC program
' A comment is followed by the single quote symbol '
' This is a comment line and so are the next three lines shown
below
' Stamps in Class - FirstProgram.BS2
' BASIC Stamp sends message to the Debug Terminal
' The next line is a Directive.
' {$STAMP BS2}
' The above directive tells the Basic Stamp Editor software that
' the part being programmed ON the board is BASIC Stamp 2
' The following directive tells that the version 2.5 of the Basic
Stamp Editor software
' is being ‘used
' {$PBASIC 2.5}
DEBUG "Hello, it's me, your BASIC Stamp!"
' The DEBUG command shown above is used to send a message
to the PC
' The END command is used to end the program
END
2. After you have typed the above program, save the program by

Then name the file as FirstProgram.bs2. Then click on the Save
button.
P.S. Nair
Running your first PBASIC Program
1. Now, run the pr
Alternatively, you can click on the
functional key F9. This will run the program on the Basic
Stamp 2 that is on the
development board and then display the result on the screen of
your computer as shown
below:
Fig. 3. Output of the FirstProgram.bs2 program.
More PBASIC Programs:
I. Now try the following program and run it after saving:

' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Hello, it's me, your BASIC Stamp!", CR
' The DEBUG...CR command shown above can be used to move
the program control
' to the next line and, optionally, to display a message
DEBUG "What is 7 x 11? ”, DEC 7 * 11
' The DEBUG...DEC command can be used to evaluate an
expression and, optionally,
' to display a message
END
P.S. Nair
II. Introducing delay in the program
Try the following program and run it after saving:
' {$STAMP BS2}
' {$PBASIC 2.5}
PAUSE 5000
' The above command delays the execution of the next command
by 5000 ms = 5s
DEBUG "Hello, it's me, your BASIC Stamp!", CR
' The DEBUG...CR command shown above can be used to move

the program control
' to the next line and, optionally, to display a message
END
III. The DO…LOOP
' {$STAMP BS2}
' {$PBASIC 2.5}
DO
DEBUG "Hello”, CR
PAUSE 1000
LOOP
' The commands between DO and LOOP are executed repeatedly
' In this program, the word ‘Hello’ will be displayed on a new
line repeatedly
' with a delay of 1second between successive displays.
END

P.S. Nair
IV. Use of Variables and Variable initialization
' {$STAMP BS2}
' {$PBASIC 2.5}
value VAR Word
anothervalue VAR Word
thirdvalue VAR Word
' value, anothervalue and thirdvalue are all variables (VAR
means a variable)
' All these variables are Word-sized (Range: 0 to 65535)
' We can also specify negative numbers by using
DEBUG…SDEC
‘ Range when DEBUG… SDEC is used: −32768 to + 32767
' These variables are assigned initial values as shown below
(Initialization)
value = 500
anothervalue = 65535
' The following lines display the current values of ‘value’ and
‘anothervalue’

DEBUG ? value, CR
DEBUG ? anothervalue, CR
' The following line modifies the variable ‘value’
value = value * 10
' The following line displays the new value taken by the
variable ‘value’
DEBUG ? value
thirdvalue = value – 9000
DEBUG “thirdvalue = ”
DEBUG SDEC thirdvalue
' DEBUG SDEC causes negative value to be displayed
END
P.S. Nair
V. The FOR…NEXT LOOP
The FOR…NEXT loop is a very convenient and powerful way
to control the number of
times a given portion of your program is executed. It has the
following syntax:
FOR Counter = StartValue TO EndValue {STEP StepValue}
…

…
NEXT
(The words written in bold letters above are key words; The
contents of the curly brackets
specify optional arguments. You can have other lines or
program between FOR and NEXT, as
in the DO…LOOP).
a. Next, try the following program and run it after saving:
' {$STAMP BS2}
' {$PBASIC 2.5}
Val_count VAR Word
FOR Val_count = 0 TO 18 STEP 6
DEBUG ? Val_count
PAUSE 500
' Half second delay is created by the above line
NEXT
END
b.Now try running the following program
' {$STAMP BS2}
' {$PBASIC 2.5}
Val_count VAR Word
FOR Val_count = 0 TO 18

' There is no STEP
DEBUG ? Val_count
PAUSE 500
' Half second delay is created by the above line
NEXT
END
P.S. Nair
An Important PBASIC Command:
The PULSOUT Command
• Physical movement of the robot is achieved in the Boe-Bot
robotics kit through the use of servo motors.
• These servo motors are controlled by sending pulses. In the
case of Basic Stamp 2, a pulse means a voltage of 5V lasting
for a short duration
• Varying the duration or width of this 5V voltage results in the
pulse width being varied
• The width of the pulse controls the duration of rotation
operation of the servo motors; the rotation of the servo
movements could be used to cause movements
• Therefore, the servo motors require high (5V) and low (0V)

voltages that last for precise durations. Such precise-duration
signals can be provided to the board by using the PULSOUT
command
• Syntax: PULSOUT PinNumber, Argument
• This command sends out a precise high pulse on the Basic
Stamp pin specified by Pin in the PinNumber. The duration
(width) of the pulse depends on the argument
• Note: The Argument does not specify the duration directly.
The actual duration and the Argument are related to each
other by the following formulae:
Actual Duration = Argument * 2 µs,
or
Argument = Actual Duration in seconds * 500,000
P.S. Nair
Fig. 4. Two pulses, each having a width of 0.13 s.
Fig. 4 Source: Robotics with Boe-Bot Student Guide Version
3.0 by Andy Lindsay,
available at
http://www.parallax.com/Portals/0/Downloads/docs/books/edu/
Roboticsv3_0.pdf

Examples of PULSOUT
1. PULSOUT 13, 80000
Here a high pulse is sent to pin number 13 of the Basic Stamp 2.
The actual
pulse duration is 80000 * 2 µs = (80000 * 2) / 1,000,000 s =
0.16 seconds
2. A program using PULSOUT and FOR…NEXT
' {$STAMP BS2}
' {$PBASIC 2.5}
L_counter VAR Word
FOR L_counter = 1 TO 100
PULSOUT 13, 850
PAUSE 20
' PULSOUT command lasts for 850 * 2 µs = 1.7ms
' PAUSE command causes 20 ms delay
‘ Time to execute the loop commands themselves (PULSOUT
and PAUSE) = 1.3 ms
' Therefore, time for one loop iteration = 1.7 + 20 + 1.3 = 23 ms
' Therefore, total servo run time (due to 100 iterations) = 23 ms
* 100 = 2.3 seconds
NEXT
END

California State University, Fullerton
College of Engineering and Computer Science
EGGN 100 Introduction to Engineering Fall 2015
Computer Engineering Design Project
Demonstration (in-class) deadline: Tuesday, September 22,
2015
Report due date (submit via TITANium): Thursday, October 1,
2015, 11:45 p.m.
Submit only one report per team
In this design project, you will use the Basic Stamp
microcontroller (hardware) and PBASIC
programming (software) to control the movement of the Boe-
Bot through various points on a 2’ x 2’ grid
on the classroom floor. The final requirement of this project is
to trace the letter-combination ‘OP’ on the
grid using a Boe-bot. The 2’ x 2’ grid is represented by the
figure shown below:
The grid has been marked with numbered points, which are also
known as nodes. An adjacent node is
defined as a node that lies immediately to the side, top, or
bottom of a given node. For example, in the
grid shown above, nodes 2 and 8 are adjacent to node 1, while
node 7 is not. The distance between any

given node, and its adjacent node, is 1 foot (12 inches). The
specifications for the project are as follows:
1. Starting at node 1, the Boe-Bot traces the letter ‘O’ on the
grid. The sequence to be followed by
the Boe-Bot for tracing this letter is as follows:
● At the beginning, the Boe-Bot is at rest with its center aligned
with node 1. The front
wheel of the Boe-Bot is facing towards node 2
● The Boe-Bot starts moving towards node 3 via node 2 (at full-
speed). When the center of
the Boe-Bot reaches node 3, the Boe-Bot pauses briefly (for 0.5
seconds), and then turns
right to proceed towards node 5 via node 4 (at full-speed)
● When the center of the Boe-Bot reaches node 5, the Boe-Bot
pauses briefly (for 0.5
seconds), and then turns right to proceed towards node 9 via
node 6 (at full-speed)
● When the center of the Boe-Bot reaches node 1, it should turn
right and pause for
2 seconds (with the center aligned on top of node 1). This
completes the tracing of the
letter ‘O’ on the grid by the Boe-bot.
2. Now the Boe-Bot traces the letter ‘P’ on the grid, starting at

node 1. The sequence to be followed
by the Boe-Bot for tracing this letter is as follows:
● At the beginning of this tracing, the Boe-Bot’s center is
aligned with node 1. The front
wheel of the Boe-Bot is facing towards node 2
● The Boe-Bot starts moving towards node 3 via node 2 (at full-
speed). When the center of
the Boe-Bot reaches node 3, the Boe-Bot pauses briefly (for 0.5
seconds), and then turns
right to proceed towards node 5 via node 4 (at full-speed)
seconds), and then turns right to proceed towards node 6 (at
full-speed)
seconds), and then turns left to proceed towards node 1 (at full-
speed)
seconds). Then it does an about-turn (180° turn). At the end of
this turn, the Boe-Bot is
at rest with its center aligned with node 1 and the front wheel of
the Boe-Bot faces
towards node 2. This completes the tracing of the letter ‘P’ on
the grid by the Boe-bot.

The completion of stages 1 and 2 described above completes the
tracing of the letter-combination ‘OP’ on
the grid by the Boe-bot.
Deliverables
1. Give a demonstration of your project to the instructor or the
student assistant before the end of
class on the demonstration deadline day
2. Turn in a project report on the report due date. The project
report should contain the following:
i. An Objective statement
ii. A Procedure: The section in which you will explain how you
went about completing the
project.
iii. Role of Team Members: In this section, you will describe
the role played by each team
member in executing the project. Please describe clearly each
member’s contribution to
the project. Also describe how each member was able to/not
able to work effectively
with team partners on the project (each person should elaborate
on his/her comments in
the same report).
iv. Program, with comments: Include the PBASIC program for
your project. The program

should include comments for improved readability.
v. Conclusions: Concluding remarks about the project
The report should be typed, using a 12-size ‘Times New Roman’
font for the main text of the report. The
left and right margins should be at least 1 inch each. The report
should be typed in a single column format
and should be single-spaced. The report should contain the
names of all contributing team members. It
should be submitted via TITANium. Each team must submit
only one report (i.e. do not submit more
than one report for the entire team)
Dr. Pradeep Nair
Introduction to Computer Engineering
Engineering
P.S. Nair
math
principles to solve problems subject to constraints such as
cost and practicality
product or outcome using available resources

tical
principles are important aspects of engineering
Computer Engineering
P.S. Nair
concerned with the design, analysis, performance estimation,
application, verification, testing and synthesis of computer
systems
desktop
computers, laptop computers, super-computers, embedded
computers
– they are present
in microwave ovens, TVs, cars, air-conditioners, smart-phones
and many other things – even though we may not notice them
readily
Computer Engineering – cont’d
P.S. Nair

hardware and
computer software
tionally, the emphasis in basic computer engineering
tends to be
slightly more on the hardware aspects although a deep
knowledge of
both hardware and software is required to design efficient
computer
systems
-related aspects find more emphasis in computer
science
computer and its design involves the application of electronics
principles
programming languages to create system software and
applications
(apps) that run on the computer hardware and perform desired
tasks
Common Computer Engineering Job Titles
P.S. Nair

neer
Computer Engineering Specialties
P.S. Nair
ty

Computer Engineering Program at CSUF
P.S. Nair
urrently offers
the following
degree programs:
-year integrated BS/MS in Computer Engineering
of hardware
and software courses, in addition to science, math and GE
courses
oundation math and science courses: 31 units
Computer Engineering Core Courses

P.S. Nair
focused on achieving the right blend of knowledge in hardware
systems, software and electronics
–
Computer Engineering, Electrical Engineering and Computer
Science
isciplinary Project
in
the senior year. This is a team project and usually involves the
design and implementation of a solution using knowledge from
more than one discipline
Computer Engineering Program: Subject Areas
P.S. Nair
stems

-related technical elective areas
Computer Engineering Program: Facilities
P.S. Nair
PGA and Digital Electronics Lab
Computer Engineering Program: Opportunities

P.S. Nair
-awards
-assistant positions
rnship opportunities
such
as the IEEE Computer Society
Career Options after Graduation

industry/government/military
P.S. Nair
Examples of Computer Engineering Designs
Computer Engineering Labs
P.S. Nair
Computer Engineering – Student Services

P.S. Nair
y ECS retention specialists
Computer Engineering One of the Top-Paid Majors
Mean wages of Engineers and Computer Scientists
ngineers – $105,450
– $93,960
– $104,340
– $85,640
– $106,930
– $80,930
– $80,740
– $93,380
– $97,870
– $85,520
– $89,930
– $85,930
– $77,910

– $106,860
Petroleum Engineers – $149,180
– $96,260
– $104,480
– $67,540
Source: Occupational Employment and Wages – May 2013,
Bureau of Labor Statistics
(Release date: April 1, 2014). Available at:
http://www.bls.gov/news.release/pdf/ocwage.pdf
Introduction to Computer EngineeringEngineering�Computer
EngineeringComputer Engineering – cont’dCommon Computer
Engineering Job TitlesComputer Engineering
SpecialtiesComputer Engineering Program at CSUFComputer
Engineering Core CoursesComputer Engineering Program:
Subject AreasComputer Engineering Program:
FacilitiesComputer Engineering Program: OpportunitiesCareer
Options after GraduationSlide Number 13Computer Engineering
LabsComputer Engineering – Student ServicesSlide Number
16Mean wages of Engineers and Computer Scientists
1
Boe-Bot Activity
The Boe-Bot robot
2
Image source: Robotics with the Boe-Bot —Student Guide

Boe-Bot Circuit Board – Rev D
3
Moving the Boe-Bot
P.S. Nair
4
-Bot is equipped with servo motors and a
microcontroller
(“brain” ), which can be programmed by the user
-Bot’s wheel movement is controlled by the rotation
of these
servo motors
The servo motors’ rotation are, in turn, controlled by
electrical pulses
applied to specific circuit pins of the Boe-Bot’s “brain”
(you!)

Controlled
movement of the Boe-Bot!
Pulses
P.S. Nair 5
(duration)
of the HIGH pulse
es are separated from each other by a
PAUSE
Pulses – cont’d
P.S. Nair 6
servo
motor clockwise
counter-clockwise

stay still
How to apply pulses to pins via
programming?
P.S. Nair
7
language
lse (at pin
N)
that lasts for Argument * 0. 002 milliseconds i.e.
Actual duration of pulse = Argument * 0. 002 milliseconds
PULSOUT Argument = Actual Duration in milliseconds * 500
PULSOUT 12, 650
generates a HIGH pulse lasting 1.3 ms at pin 12, causing the

servo
motor connected to pin 12 to rotate full-speed clockwise
Example Code: Moving Boe-Bot for 3 seconds
8
' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Boe-bot is running the program“
counter VAR Byte
FOR counter = 1 TO 122 'Runs the FOR loop 122 times;
initially, counter = 1
PULSOUT 13, 850 'Generates 1.7 ms pulse at pin 13 (pin
13 servo rotates counterclockwise)
PULSOUT 12, 650 ' Generates 1.3 ms pulse at pin 12 (pin
12 servo rotates clockwise)
PAUSE 20 'Pause for 20 ms between pulses
NEXT 'Increment counter by one and repeat
loop (repeat till counter = 122)

'Time overhead due to the number of
instructions in the loop = 1.6 ms
'TIME TAKEN FOR ONE LOOP EXECTION =
1.7 + 1.3 + 20 + 1.6 = 24.6 ms
'TOTAL TIME OF BOE-BOT MOVEMENT=
122 * 24.6 ms = 3 seconds (approx.)
END
P.S. Nair
Exercises
9
symbols (??) with actual numbers to achieve desired Boe-Bot
movement
-Bot
P.S. Nair

Exercise 1: Moving Boe-Bot backwards for 5 seconds
10
' {$STAMP BS2}
' {$PBASIC 2.5}
counter VAR Byte
FOR counter = 1 TO ??
PULSOUT 13, ??
PULSOUT 12, ??
'TIME TAKEN FOR ONE LOOP EXECTION =
1.7 + 1.3 + 20 + 1.6 = 24.6 ms
END

P.S. Nair
Exercise 2: Keeping the Boe-Bot still for 3 seconds
11
' {$STAMP BS2}
' {$PBASIC 2.5}
counter VAR Byte
FOR counter = 1 TO 122
PULSOUT 13, ??
PULSOUT 12, ??
END

P.S. Nair
Exercise 3: Identify the wheel controlled by pin 12
12
' {$STAMP BS2}
' {$PBASIC 2.5}
counter VAR Byte
FOR counter = 1 TO 122
PULSOUT 13, ??
PULSOUT 12, ??
'Time overhead due to the number of instructions
in the loop = 1.6 ms
END

P.S. Nair
13
Questions??
P.S. Nair
14
Thank you!!
P.S. Nair

P.S. Nair Tutorial Robotics with Boe-Bot and PBASIC .docx

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