Beyond Lego Mindstorms Analytical and Experimental Minds v3

Beyond Lego Mindstorms: Analytical and Experimental Minds
Tri Kurniawan Wijaya

Gunawan

Arya Tandy Hermawan

Department of Computer Science,
Sekolah Tinggi Teknik Surabaya
Surabaya 60284, Indonesia
tritritri@stts.edu

Departement of Electrical
Engineering, Sepuluh Nopember
Institute of Technology
Surabaya 60111, Indonesia
admin@hansmichael.com

Information Technology Graduate
Program,
Sekolah Tinggi Teknik Surabaya

Surabaya 60284, Indonesia
arya@stts.edu

Abstract
Lego Mindstorms is a robotic tool which perfectly safe
to use in the educational environment. Even children and
teenager can touch and program it without a fear about
the electricity. Because of this, we develop the use of Lego
Mindstorms robotic tool to arouse analytical and
experimental minds of the students.
In this paper we presented the important of thinking
and finding ideas and then implementing it to solve the
problem given. In fact, there are many things for students
to do. Students have to test and change their not-worked
solution many times before they find the worked solution
and reach the goal. These are what required in
constructivist learning and constructionist educational
philosophy which is very important and absolutely have a
big and positive impact in motivating students to learn
and explore the world surrounds them.

among families with children‖. Finally, the MIT Media
Lab sought to create a new and publicly visible model of
academic research that emphasizes the public impact of
ideas, fosters idea transfer between academic research
groups and corporate sponsors, and encourages
community outreach. Ultimately, the Lab provided an
environment for the research that led to the Mindstorms
product to grow and mature.

1.2. RCX

1. Lego Mindstorms
1.1. History
The story behind LEGO Mindstorms is, in reality, a
fascinating narrative of how three organizations: Resnick
and Papert’s Epistemology and Learning research group,
the LEGO Corporation, and the MIT Media Laboratory—
engaged in a complex social interaction, which shaped the
evolution of the technology [1]. Each group had its own

interests and ideas of what success meant. Thus, each
organization influenced the development of the
Mindstorms product and its Media Lab prototypes in
different ways.
The Epistemology and Learning group, for instance,
endeavored to create and disseminate new Constructivist
approaches to learning. The LEGO Company also aspired
to provide Constructivist approaches to learning, while
wanting their brand ―to be the strongest in the world

Figure 1. RCX Mindstorms
Finally, in 1997 Lego released RCX Mindstorms (see
figure 1). Its programmable brick offered a 16MHz H8
CPU with 32 KB onboard RAM for firmware and user
programs. Since the firmware had a 26 KB footprint, user
programs were limited to approximately 6 KB of
bytecodes. Its I/O complement featured three sensor ports
(ports 1, 2, and 3), an infrared (IR) transceiver port for
program download, and three motor ports (ports A, B, and
C).

The RCX supported ―immediate command‖ and
―program command‖ modes, which meant it could be

controlled remotely through IR signals or controlled
directly through an onboard program. The immediate
command mode allowed third-party packages such as
LeJOS [2] and RCXLisp [3] to support AI projects such
as robotic navigation or planning by running memory
intensive, floating point portions of system code on a PC
while running smaller remote-control programs on the
RCX.

wireless Bluetooth connection also can be used for
uploading and downloading.
1.4.2. Loudspeaker. A program with sounds can be made
and the output sounds can be listened through the
loudspeaker when the program run or let the robot
communicate with the environment.

1.3. NXT

Nine years later Lego released the NXT (see figure 2).
The hardware and firmware of the new kit’s
programmable brick feature several advances over the
RCX design. These include a local file system on 256KB
flash RAM, 64KB RAM for program execution, a 48MHz
ARM7 CPU with support for Bluetooth radio frequency
(RF) communication, a large 100x64 pixel LCD display, a
USB 2.0 port for program download, three output ports
for attaching motors (ports A, B, and C) and four sensor
ports (ports 1, 2, 3, and 4).

Figure 3. NXT details

Figure 2. NXT Mindstorms
User programs can be as large as 160 KB (more if
system sound files are removed from the flash RAM
drive). NXT firmware uses the 64KB onboard RAM to
allocate memory for programs in execution. The NXT
supports ―immediate command‖ and ―program command‖
modes, but because it uses RF communication, line-ofsight issues with the RCX’s IR technology have been

eliminated.

1.4. Further details about NXT
Here the more details specifications about NXT will be
discussed. See figure 3 to understand further about NXT
brick.
1.4.1. USB Port. USB cable can be connected to the USB
port and download programs from the computer to the
NXT (or upload data from the NXT to the computer). The

1.4.3. Servo motors. The three servo motors give you
agent the ability to move (see figure 4). With the Lego
Mindstorms NXT software the motors are even able to
synchronize, so that an agent having one motor for each
side could move in a straight line.

Figure 4. Servo motor
1.4.4. Built-in Rotation Sensor. The motors can be used
either as motors and or as sensors, because each motor has
a built-in rotation sensor. This lets you control your

agent’s movements more precisely. The rotation sensor
measures motor rotations in degrees or full rotations
(accuracy of ± one degree). This means that you could set
a motor to turn for example 45°. The built-in rotation
sensor in each motor also lets you set different speeds for
your motors (by setting different power parameters in the
software).

1.4.5. Touch Sensor. The touch sensor (see figure 5)
detects when it is being pressed by something and when it
is released again.
Figure 7. Light Sensor

Figure 5. Touch Sensor
1.4.6. Sound Sensor. The sound sensor (see figure 6) can
detect both decibels (dB) and adjusted decibels (dBA).
 dB: in detecting standard (unadjusted) decibels, all
sounds are measured with equal sensitivity. Thus,
these sounds may include some that are too high or
too low for the human ear to hear.

 dBA: in detecting adjusted decibels, the sensitivity
of the sensor is adapted to the sensitivity of the
human ear.
In other words, these are the sounds that human ears
are able to hear. The sound sensor can measure sound
pressure levels up to 90 dB – about the level of a
lawnmower. The sound sensor readings on the NXT are
displayed in percent. The lower the percent, the quieter is
the sound.

1.4.8. Ultrasonic Sensor. The ultrasonic sensor (see
figure 8) can be used to measure distance and detect
movement. Therefore it could be used for obstacle
avoidance. The distance is measured in centimeters and in
inches. The sensor is able to measure distances from 0 to
255 centimeters with a precision of ± 3 cm.

Figure 8. Ultrasonic Sensor
The sensor uses the same scientific principle as bats: it
measures distance by calculating the time it takes for a

sound wave to hit an object and return –just like an echo.
Large sized objects with hard surfaces return the best
readings. Objects made of soft fabric or those are curved
(like a ball) or are very thin or small can be difficult for
the sensor to detect. Note that two or more ultrasonic
sensors operating in the same room may interrupt each
other’s readings.

2. Related work
Figure 6. Sound Sensor
This list of examples can be used as an approximate
reference:
 4-5% is like a silent living room
 5-10% would be someone talking some distance
away
 10-30% is normal conversation close to the sensor or
music played at a normal level
 30-100% are people shouting or music being played
at a high volume
1.4.7. Light Sensor. The light sensor (see figure 7)

enables the robot to read the intensity of reflected light
and display intensity in percent.

Previous research has shown that Lego Mindstorms is a
powerful educational kit, suitable for teaching
introductory science concepts, technology, and
programming [4]. The use of the Lego Mindstorms allows
students to learn and have fun at the same time while
working within a motivational environment [5].
Ricca, Lulis, and Bade (2006) observed that Lego
Mindstorms had a positive effect on problem solving
skills in a fifth grade classroom [6]. They decide to
formally test the use of the robots on critical thinking
skills in grades five through eight.
But Lego Mindstorms is not all about fun. In more
serious way, Klassner and McNally (2007) demonstrate
the possibilities offered by the new NXT platform for
Computer Science artificial intelligence curricular
development [7]. They demonstrate the curricular
materials developed in the LMICSE archive (Lego

Mindstorms in Computer Science Education), including
autonomous mobile robot localization and SLAM.
Different with Ricca and Klassner, Karantratou and
Panagiotakopoulos (2008) investigated the way primary

school teachers handled the process of converting an
algorithm to a program in Lego Mindstorms programming
tool [4]. They find that the teachers composed the
algorithms easily in every step. The teachers used the
natural language to make the pseudo-codes and then
converted them to a program in a simple manner.

3. Basic ideas
The exploitation of the Lego Mindstorms in education
falls in step with the concept of constructivist learning and
the constructionist educational philosophy. Papert has
mentioned that constructionism is built on the assumption
that children will do best by finding for themselves the
specific knowledge they need; organized or informal
education can help most by making sure they are
supported morally, psychologically, materially, and
intellectually in their efforts [8]. These theories argue that
children are much more motivated for learning when they
can explore the world that surrounds them in a natural
way.
In a constructionist environment, students act like
―real-world‖ scientists, inventors and engineers. So, as a
result, students are in much closer contact with the truly
important ideas of science and engineering. They do not
simply learn facts, equations, and techniques. They learn a
way of thinking critically and systematically about
problems, and especially in view of the fact that they learn
about the problem-solving process itself.
In contrast with the traditional learning environments,
the constructivist approach provides tools, which allow
children to build their own knowledge. In constructivism,
children are explorers of knowledge rather than simple
receivers of knowledge. Lego Mindstorms is one of the
tools.
On the other hand, computational thinking is a
fundamental skill for everyone, not just for computer
scientists. However, computer programming is a difficult
process. Beyond knowing the syntax of a programming
language, this cognitive process requires several skills.
Both analytical and experimental minds need
computational thinking. But, rather than achieve them
through computer programming, we used constructivist
and constructionist approach with Lego Mindstorms as the
tool. Students will brainstorm to find an idea, build the
robot, and then program it to solve the problem.

4. Analyze and experiment
Problem solving and critical thinking are two abilities
widely considered important outcomes of education. In
addition to the need for students to develop critical
thinking and problem solving skills, there is need for
research into the development of these skills in students.

Relatively little is known about the processes by which
these students’ problem solving abilities grow, and it is
therefore difficult to integrate the development of these
cognitive skills into the standard curriculum of the
traditional school.
While there are many environments that may promote
the development of problem solving and critical thinking,
the use of an environment that involves robotics may be
appropriate for students for several reasons. First, the
design, construction, and programming of robots can
obviously be used to address standards: ―design a device
that will be useful in solving the problem‖. Second, from a
student point of view, the work with robots can be quite
motivational. Third, the use of robots may provide for
opportunities to collect rich data about student thinking in
situ. Fourth, a robotics curriculum would be in line with
recent emphasis from the government on the promotion of
science, technology, engineering, and mathematics
education.
The motivation for using Lego Mindstorms was to put
a practical twist to student learning which led to awaken
analytical mind. Students can use the scientific method
when using the robots. The students had to read and
follow directions, make a hypothesis, test their hypothesis,
record results, and implement corrections for each run.
Once a challenge was completed, it needed to be
reproduced to validate results.
The following will explain how Lego Mindstorms can
arouse analytical minds on every student.

4.1. Project 1: Observing the impact of gear and
tire on the speed
Using Lego bricks, light and sound sensors, motors,
and gears, teams built robots to complete class
assignments and eventually compete in a Lego Classroom
Tournament. Groups of three students each, with each
member having a specific job—builder, programmer, and
scribe—were created; each member had to have
knowledge of the other two jobs.
Building the robots was the first step. The kit used was
the Lego Mindstorm kit, Team Challenge Set; parts used
depended on how the students built their robots and what
functions they were trying to achieve. Time was spent on
basic robot design and function. Students needed to be
able to change their robot’s tires and gears with little or no
rebuilding of the basic structure. The robot shown in
figure 9 (the famous RCX TankBot) will be the perfect
basic robot design for the students although another
design also applicable.



Figure 9. RCX TankBot
The first exercise in basic geometry (radius and
circumference) was conducted by measuring the
circumference on all the tires on the bots and recording
the results. This was done by wrapping a string around the
tire, marking it, and measuring the string for
circumference. Students then measured the diameters of
the tires, recorded the results in journals, multiplied all
results by 3.14, and calculated the circumference. The
calculated results were compared to the measured results.
Various experiments using the robots based on [6]
were conducted. The first task involved the understanding
of the relationship between tire and gear size. Students ran
their robots using different size tires and gears, and
compared the results. Overviews of these experiments
follow.
Task 1:
 Place tires on robots, a set at a time
 Program their robot to go ten seconds
 Record the results after each run to determine how
far their robot has traveled with direct drive.
Task 2:
 Put gears on their robots; start with a small gear on
the motor and the medium gear on the axles
 Run their robot using all three different size tires to
see how far their robot has traveled with this type of
gearing
 Record their results after each run
Task 3:
 Place small gear on the motor and the big gear on the
axles
 Run their robot with all three sets of tires and record
results after each run
Task 4:
 Place the medium gear on the motor with the small
gear on the axles
 Run all three tires and record their results after each
run
Task 5:
 Place the medium gear on the motor and the large
gear on the axles
 Run their robot with all three different tires and
record their results after each run
Task 6:

Place the large gear on the motor and the small gear
on the axles
 Run their robot using all three sets of tires and
record their results
Task 7:
 Place large gear on the motor and the medium gear
on the axles
 Run their robot and record their results
Results were collected, written in journals, compared
and analyzed. They have to take a connection between the
gear, the tire and the distance travel by their robot.
Although not all students might understand gear ratio,
they did understand how different size gears coupled with
different sized tires can affect a robot’s travel. Students
wrote reports comparing, contrasting and analyzing the
results.

4.2. Project 2: Expanding horizon
The project still is a team project and is supported by 6
worksheets, corresponding to 6 tasks. The project was
adopted from [4]. It is a project about car robot. For each
task, the team had to:
(a) Make the appropriate algorithm - think and write on
a paper sheet the sequence of actions in their natural
language (a pseudo-code) in order to describe the
algorithm.
(b) Build the robot they need. The robot should be a carlike robot. The same robot building may use to solve
more than one set of problem.
(c) Convert the pseudo-code to a program using any
Lego Mindstorms programming environment, in
order to verify the algorithm made and to program
the car robot.
(d) Test it.
Every time, the team could see the result of their
program and could make it again and again, if necessary,
trying to find out the correct solution. Here the six tasks
on project 2:
Task 1:
 Move the car forward for a specific time interval and
then stop it
 Move the car forward for a specific time interval,
stop it for a specific time interval, move again
backward for a specific time interval and then stop it.
Task 2:
 Move the car forward for a random time interval
(between 0 - x seconds) and then stop it.
 Move the car forward for a random time interval
(between 0 - x seconds), stop it for a specific time
interval, move it backward for a random time
interval and then stop it.
Task 3:



Turn the car around for a specific time interval and
then stop it.
 Turn the car around (in the same direction as above)
for a random time interval (between 0 – x seconds)
and then stop it.
 Turn the car around (in the same direction) for a
random time interval (between 0 – x seconds), after
this turn it round again but to the opposite direction
for a random time and then stop it.
Task 4:
 Mount a light sensor on the car.
 Place the car on different locations in the room.
 Keep writing the different values of the light sensor.
 Keep writing again the different values of the light
sensor when a white or a black paperboard is been
placed about 15-25 centimeters in front of the car.
 Keep writing the value of the light sensor without
any paperboard in front of the car.
Task 5:
 The car is stopped.
 Move the car forward when a black paperboard is
been placed in front of the sensor and not responding
when a white paperboard is been placed in front of
the sensor.
Task 6:
 On the car a light sensor and a green lamp are
mounted.
 Turn the car around for a random time (between 0 –
x seconds), then stop it and if a black paperboard is
placed in front of the car then the green lamp should
turn on, otherwise if a white paperboard is placed in
front of the car then nothing should happen.
When all team complete the project, a discussion took
place based on a set of questions (semi-structured group
interview), in order to evaluate the whole procedure and
explore the opinion with regards to:
(a) The brainstorming process to find an idea to solve
the problem.
(b) The conversion of a pseudo-code into a program in
the Lego Mindstorms programming environment.
(c) The impact of the building of the robot on the
program. Why the different (robot) buildings need
the different program in order to solve the same
problem?
All discussions were recorded, in order to analyze it
afterwards.

5. Conclusion
All of the process in turning their own ideas into reality
(robot building and programming) will deliver them to an
experience in becoming a ―mini‖ scientist. They will
experiment and experiment again just like the real
scientist. When the first idea does not work, they would

have to implement the second idea. The second idea does
not work, they will analyze why it does not work, what is
the problem, develop a new solution, and then implement
it for the third attempt. The process will repeat again and
again until they find the satisfied solution. The
experiences do not occur in traditional school, even in
computer programming. In traditional school, student only
ask to receive information, write it down, without
practicing it to their real life, without build and
development ideas. In computer programming, it is
enough with the good program. But in this case, Lego
Mindstorms robotic (and robotic application elsewhere), it
is not enough with the right program, but also the right
robot building.
By completing each task, students know by their own
effort that building a robot without a program to operate it
will be useless because the robot can not do anything (the
robot can not move to anywhere). But, a right program
without the right building also would be disappointed. In
addition, an amazing robot building without supported by
the right program is useless.
Lego Mindstorms is an important tool that motivates
students to think, analyze, create, build, develop, and
research logically and rationally. It also can be used to
help students in language development through writing
down the process of how the solved the problem.

6. References
[1] D. Mindell, ―LEGO Mindstorms The Structure of an
Engineering (R)evolution‖, 6.933J Structure of
Engineering Revolutions, 2000.
[2] Bagnall, B., Core LEGO MINDSTORMS
Programming: Unleash the Power of the Java Platform,
Prentice Hall, New Jersey, 2002.
[3] F. Klassner, ―Enhancing Lisp Instruction with
RCXLisp and Robotics‖, 35th SIGCSE Technical
Symposium on Computer Science Education, ACM Press,
Virginia, 2004, pp. 214-218.
[4] A. Karatrantou, C. Panagiotakopoulos, ―Algorithm,
Pseudo-Code and Lego Mindstorms Programming‖,
International Conference on Simulation ,Modelling and
Programming for Autonomous Robots, Venice-Italy, 3-4
November 2008, pp. 70-79.
[5] M. Garcia, H. Patterson-McNeill, ―Learn how to
develop software using the toy Lego Mindstorms‖, 32nd
ASEE/IEEE Frontiers in Education Conference, Boston,
6-9 November 2002.

[6] B. Ricca, E. Lulis, D. Bade, ―Lego Mindstorms and
the Growth of Critical Thinking‖, Dominican University,
2006.

[11] S. Kelly, A. Schuster. ―Application of a Fuzzy
Controller on a Lego Mindstorms Robot‖, University of
Ulster at Jordanstown, Northern Ireland, 2004

[7] F. Klassner, M. McNally, ―Demonstrating the
Capabilities of MindStorms NXT for the AI Curriculum‖,
American Association for Artificial Intelligence, 2007.

[12] M. McNally, F. Klassner, C. Continanza, ―Exploiting
MindStorms NXT: Mapping and Localization Projects for
the AI Course‖, American Association for Artificial
Intelligence, 2007.

[8] Papert, S., The Children's Machine. Rethinking School
in the Age of the Computer, Basic Books, New York,
1993.
[9] Pfeifer, R., Tutorial for Programming the LEGO®
MINDSTORMS™ NXT, University of Zurich, Department
of Informatics, Artificial Intelligence Laboratory, 2007.

[13] C. Langer, C. Strothotte, ―The Benefits of Integrating
Lego Mindstorms into Design Education Course Media
Systems‖, International Conference on Engineering and
Product Design Education, Northumbria University,
Newcastle Upon Tyne, United Kingdom, 13-14
September 2007.

[10] F. Klassner, ―A Case Study of LEGO Mindstorms
Suitability for Artificial Intelligence and Robotics Courses
at the College Level‖, SIGCSE, ACM Press, Kentucky, 27
February – 3 March 2002, pp. 214-218.

[14] J. Simpson, C.L. Jacobsen, M.C. Jadud, ―A Native
Transterpreter for the Lego Mindstorms RCX‖,
Communicating Process Architectures, IOS Press, 2007,
pp. 339-348.