Robotics - Quia · AT000 - Robotics Module 1: Introduction to Robotics 3 Module 1: Introduction to Robotics Module Objectives 1. Introduce robots to students. 2

Robotics

Module 1: Introduction to Robotics

PREPARED BY

IAT Curriculum Unit

August 2008

© Institute of Applied Technology, 2008

AT000 - Robotics

Module 1: Introduction to Robotics 2

AT000 - Robotics


Module 1: Introduction to Robotics

Module Objectives

1. Introduce robots to students.

2. Understand the main components of a robot and their functionality.

3. Give examples on robots and their tasks.

4. Introduce LEGO MINDSTORMS NXT to students.

5. Explain NXT Brick functionality and menus

6. Explain functions of LEGO MINDSTORMS NXT Motors & Sensors.

7. Programming using NXT brick.

Module Contents

1 Introduction 4

What is a Robot? 4

Robots Movements Examples 4

2 Robots Components 5

3 LEGO MINDSTORMS NXT 7

What is LEGO MINDSTORMS NXT? 7

LEGO MINDSTORMS NXT Main Components 7

LEGO MINDSTORMS NXT Sensors 9

4 NXT Brick 11

NXT Brick Buttons & Menus 11

Learning Tasks -1 17

5 Introduction to LEGO MINDSTORMS NXT

Sensors and Motors

Learning Tasks -1

AT000 - Robotics


1. Introduction

4. What is a Robot?!

A robot is a machine which senses, plans and acts in a way to

perform a task.

• Senses: collect information about the environment using

sensors like your eyes, ears, etc. • Plans: make decisions based on the information collected by

the sensors where the robot has a brain called microcontroller. • Acts: generate an action based on your decision, like

moving, speaking, etc.

4. Robots Movements Examples

Robots are able to move in different ways depending on its

task.

Examples on robot Movements:

• Rotate

• Convey

• Walk

• Swim

• Fly

• Bend, etc.

AT000 - Robotics


Examples on Robots and their Movements:

Videos:

• Sony Robot

• Einstein • Rolling

• Snake

• Walking Robot

2. Robots Components

The robot may have the following

components to be able to perform a

task:

a. Physical Components: are the

components used to build a robot

and they are as follows:

� Microcontroller: is a

computer-on-a chip, they are

designed to execute only a

single specific task to control a

single system. The Microcontroller is the brain of the robot that can think and make decision- like your brain.

Fig. 1.1: Examples on Robots

and their Movements

AT000 - Robotics


� Sensors: They are the robot

Senses like our eyes, ears,

mouth, nose and our skin.

Robots could sense the

environment using the sensors.

� Motors or Actuators: They are

the action parts which help the

robot to move or perform a

specific task, like our legs,

hands and voice.

� Other Components: like Gears,

axles, beams, connectors,

wires and wheels. The robot

will have other parts to support

the main physical component.

b. Software Component: it depends on

you, you will tell the robot what to

do under a certain condition and

you’ll assign tasks to the robot, how?

You will program it and download the program to its brain (Microcontroller)

to be able to perform the task you

want.

Fig. 1.2: Microcontroller – robots

brain

Fig. 1.3: Sensors – Human

senses

A

Microcontroller

is a Robot

MIND

AT000 - Robotics


3. LEGO MINDSTORMS NXT

4. What is LEGO MINDSTORMS

NXT

It is a Programmable Robotic kit, the

one you will be using to build up

your own robot and program it in order to perform a task.

As shown in the fig 1.4 using LEGO MINDSTORMS NXT kit, you can build

your robot from Lego, with its

Motors, sensors and main

Microcontroller – NXT Brick.

Fig. 1.4: LEGO MINDSTORMS

NXT Kit.


Main Components

The Main Parts of Lego

MINDSTORMS is the same as the

parts of any Robot; it has the

Following parts as shown in the

figure below:

• NXT Brick.

• Sensors:

o Touch Sensors.

o Light Sensor. o Ultrasonic Sensor.

o Sound Sensor.

• Motors.

• Other components like gears,

axels and wheels.

Fig. 1.5: LEGO MINDSTORMS

NXT Brick, Motors and Sensors.

AT000 - Robotics


NXT Brick An intelligent, computer-controlled LEGO® brick, the NXT is the brain of the LEGO MINDSTORMS® Education robot.

Touch Sensors Enable the robot to respond to obstacles in the environment.

Sound Sensor Enables the robot to respond to sound levels.

Light Sensor Enables the robot to respond to variations in light level and color.

Ultrasonic Sensor Enables the robot to measure distance to an object and to respond to movement.

AT000 - Robotics



Sensors

As mentioned before that each robot

has a brain which is the NXT brick for

LEGO MINDSTORMS NXT, shown in

figure 1.6.

The robot also has sensors which

helps the robot to detect the

surrounding environment just like

the way you do!! How?? See the

figure below.

Fig. 1.6: NXT Brick.

AT000 - Robotics


This is your sensors connected to your brain, Right??

This LEGO MINDSTORMS NXT brain with its sensors connected at the bottom

and its motors connected to it at the top.

AT000 - Robotics


Sensors are Inputs for your program or the robot, so you can build actions using the information from the sensors. Motors are the outputs of the robot where the action is applied, depending on the sensors reading, Motor ports, Sensor Ports & USB port for downloading programs are shown in the figure below.

Fig. 1.7: Ports for Sensors on the NXT brick are shown in the figure below and numbered from 1-4.

Fig. 1.8: NXT brick Sensor ports.

Motor Ports Sensor Ports USB Port – PC

As shown in this figure- four

ports for the sensors.

The figure shows the default

connection of the sensors.

AT000 - Robotics


Motors have three ports since there are three motors for each kit, the Motor ports are labeled A, B and C as shown in the figure below:

Fig. 1.9: NXT brick output (motor) ports.

The figure shows the default

motor connection in case when

a lamp is also connected.

Lamps

AT000 - Robotics


4. NXT Brick

4.1. NXT Brick Buttons & Menus

The NXT brick is the brain of the LEGO® MINDSTORMS® Education robot. It is a computer-controlled LEGO brick that provides programmable, intelligent,

decision-making behavior.

Output ports The NXT has three output ports labeled A, B, and C for Motors or Lamps.

USB port Connect a USB cable to the USB port and download programs from your computer to the NXT.

Bluetooth icon The Bluetooth icon shows the current status of any wireless Bluetooth connections. If there is no Bluetooth icon shown, Bluetooth is Off.

Power Plug If you are using the rechargeable battery and need to recharge it.

You don’t need a computer to program a robot. Using the NXT Program submenu, you can make many programs without your computer.

AT000 - Robotics


Running icon When the NXT is turned on, the running icon spins. If the running icon stops spinning, the NXT has frozen and you must reset it.

Battery level The battery icon displays the NXT power level. When the battery power is low (below about 10% capacity), the battery icon flashes on and off.

Loudspeaker When sounds are included in a program, you can hear them through the Loudspeaker.

NXT buttons Orange: On/Enter. Light grey arrows: Navigation, left and right Dark Grey: Clear/Go back.

Input ports The NXT has four input ports for attaching sensors. The sensors must be attached to port 1, 2, 3, or 4.

Turning off your NXT Press the Dark Grey button until you see this screen. Press the Orange button to turn off the NXT. Press the Dark Grey button to go back to the NXT main menu.

AT000 - Robotics


To Turn on the NXT

After turning on the NXT brick you will be

able to access its menus, to move between

menus use the triangle buttons NXT brick menus are as follows:

1. My files

2. NXT Program

3. Try Me 4. View

5. Settings

6. Bluetooth

Fig. 1.10: to switch on the NXT

brick.

Fig. 1.11: triangle buttons.

1. My Files

In the My Files submenu you can store all the programs that you have made on the

NXT or downloaded from your computer.

To Open My Files submenu click the orange

button of the NXT Brick, the following

subfolders will appear:

Fig. 1.12: My files menu.

Fig. 1.13: Orange button.

Software Files

Programs you have

downloaded from your computer.

NXT Files

Programs you have

made on the NXT.

Sound Files

Sounds that are part of

a program that you

download.

AT000 - Robotics


2. NXT Program

You don’t need a computer to program a

robot. Using the NXT Program submenu, you can make many programs without

your computer.

Opening the NXT program will provide you

with the default connections for the Motors

& the Sensors as shown in figure 1.12.

Port 1: Touch Sensor Port 2: Sound Sensor

Port 3: Light Sensor

Port 4: Ultrasonic Sensor

Port B/C: L/R motors

You can start building your program by

clicking the orange button again; NXT

program will show you the list of actions

you could use to write a program, the

figure below shows the screen of the NXT

brick.

To go over the options for writing the

program use the NXT buttons

To select an action like Forward press the

NXT button .

Once you finish your program, you can run

it using the NXT button . You can save

your program and run it later.

x

Fig. 1.14: NXT Program menu.

Fig. 1.15: NXT Program menu –

default connections.

Fig. 1.16: NXT brick Programming options.

AT000 - Robotics


3. Try Me

The Try Me feature allows you to

experiment with the Sensors and Motors

using programs that are ready to run.

Using Try me you could try the following:

� Try Sound: try the sound sensor.

� Try Touch: try the Touch Sensor � Try Light: try the light sensor.

� Try Ultrasonic: try the ultrasonic

sensor.

� Try Motor: try the Motors.

Fig. 1.17: Try Me Menu.

4. View

In the View submenu, you can do a quick

test of your Sensors and Motors and see

the current data for each.

Using View menu you could view the

following:

� Sound: view the sound strength and

level as a percentage.

� Touch: shows an indication

whenever the touch sensor is

pressed, released or bumped.

� Light: shows light strength of the

light sensor in different light

conditions and for different colors. � Distance: shows distance in cm or

inches using the ultrasonic sensors.

� Motor: shows the number of

rotations or degrees of a connected motor.

Fig. 1.18: Try Me Menu

5. Settings

In the Settings submenu, you can adjust

the different settings of the NXT, such as

Loudspeaker, volume or Sleep mode. In

this submenu, you can also delete the

programs that you have stored in the NXT

memory.

Fig. 1.19: Settings menu.

AT000 - Robotics


Using the Settings menu you can adjust

the following:

� Sleep Mode: You can set your

NXT to be turned off after 2, 5,

10, 30 or 60 minutes when it is not being used.

� Change Volume: Here you can

adjust the volume of the NXT

speakers in a range of 0 (Off) to 4 (Loud).

� Delete all programs: You are

able to delete the programs from four subfolders: Software files,

NXT files, Sound files, and Try Me

files.

6. Bluetooth

� In the Bluetooth submenu, you can set

a wireless connection between your NXT

and other Bluetooth devices, such as

other NXT units, mobile phones, and computers.

� You can download programs without

using the USB cable

Fig. 1.20: Bluetooth menu.

AT000 - Robotics


Learning Tasks -1:

5. Use the NXT brick View menu to do the following:

a. View the reading of the sound sensor in:

i. dB: all actual sound, including sounds too high or low for

the human ear to hear.

1. connect the sound sensor to one of the input ports 1-

4

2. View � Sound dB �Select the port the sensor is

connected to.

3. What kind of readings does the NXT brick shows?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

4. What is the use of sound sensor?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

ii. dBA: The sounds humans ears are able to hear.

1. Change the port the sensor is connected to. 2. View � Sound dBA �Select the port the sensor is

connected to.

3. What is the difference between the readings in dB

and dBA?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

b. View the readings of the light sensor:

i. Connect the light sensor to one of the input ports for

reflected light readings. 1. View � Reflected light�Select the port the sensor is

connected to as shown in the figure below.

AT000 - Robotics


2. Pass the light sensor over different colors and record

the values.

Color to test Sensor readings

3. What is the use of the light sensor in this case, is the sensor flood light on or off?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

ii. Connect the light sensor for ambient light readings.

1. View � Ambient light�Select the port the sensor is

connected to as shown in the figure below.

2. the ambient light reads the light around the sensor,

so view the reading of the sensor for the following

cases:

Light Intensity Sensor readings

Dark

Medium light

Bright light

AT000 - Robotics


3. Describe the reading of the light sensor for different

light intensities.

……………………………………………………………………………………………………

……………………………………………………………………………………………………

4. Is the sensor flood light on or off?

……………………………………………………………………………………………………

iii. Connect the light sensor to View light sensor readings 1. View � Light sensor �Select the port the sensor is

connected to.

2. View the readings for different light intensities. 3. What is the different between this reading and the

previous readings?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

4. What is the light sensor used for?

1. …………………………………………………………………………………………………

2. …………………………………………………………………………………………………

c. View the readings of the touch Sensor:

i. Connect the touch sensor to one of the input ports.

ii. View � Touch �Select the port the sensor is connected to.

iii. Press and release.

iv. What is the reading for the following:

Sensor NXT brick readings

Pressed

Released

d. View the readings of the ultrasonic sensor:

i. Connect the ultrasonic sensor to an input port.

ii. View � ultrasonic cm �Select the port the sensor is

connected to.

iii. Change the distance between the sensor and a surface (for

example: your hand) & monitor the difference.

AT000 - Robotics


iv. What does the ultrasonic sensor measures, what is the

unit?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

v. Now under the View menu select ultrasonic inch, go

through the previous procedure and observe the difference

between the two readings, what is the unit of the

measurement?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

e. View the readings of the motor rotations:

i. Connect the motor to one of the motors ports A-C.

ii. View � Select Motor rotations � select the port of the

motor.

iii. Rotate the motor manually by hand or by attaching a wheel

to the motor to rotate the motor as shown the figure below.

iv. What are the readings of the NXT brick and how it is

related to the motors rotations?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

v. Now under View � Motor degrees � select the motor port.

AT000 - Robotics


vi. Rotate the motor manually or as shown in the figure above,

rotate it clockwise and counter clockwise

vii. Monitor the readings of the NXT brick; describe the motor

readings as rotating in both directions.

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………

viii. What does the reading shows, what is the number

displayed on the NXT brick?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………

5. Use Try me submenu & try the following:

a. Try touch sensor. i. Connect the touch sensor to its default port

(port 1).

ii. Use Try touch under Try Me menu to try the sensor.

iii. Press and release, describe what happens?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………

b. Try Sound Sensor.

i. Connect the Sound Sensor to its default port (port2).

ii. Connect one of the motors to port B of the

NXT brick

iii. Use Try Sound under the Try Me menu to try the sensor

iv. Speak softly and then loudly, what is the relation between

the run of the motor & the sound level?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………

c. Try Light Sensor

i. Connect the Light sensor to its default port

(port3)

ii. Under Try Me menu, run try Light to try the

sensor.

iii. Listen to the sound generated by the NXT brick while

AT000 - Robotics


applying different colors & light levels to the light sensor.

iv. Explain the use of the light sensor with colors and different

light intensities?

……………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………………………………………………………………………………

d. Try the Ultrasonic sensor i. Connect the ultrasonic sensor to its default

port (port4) Under Try Me menu, run try

Ultrasonic to try the sensor. ii. Listen to the sound generated by the NXT

brick while applying different distances to the ultrasonic

sensor

iii. What happens if you put your hand on the sensor? Describe

the relation between the sound as an alarm and the

distance applied to the sensor?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

e. Try the Motor.

i. Connect one of the motors to port A.

ii. Run try motor from Try Me menu.

iii. Rotate the motor manually by your

hand and listen to the sound generated by the NXT brick,

start from low speed of rotating to fast speed of rotation,

and describe the sounds as increasing the speed of

rotation.

…………………………………………………………………………………………………

……………………………………………………………………………………………………………

AT000 - Robotics


5. Introduction

Identify the parts shown in figure 1.21 and their names.

Motors

Ultrasonic Sensor Light Sensor Sound Sensors

Touch Sensor

NXT Brick

Cables

Fig. 1.21: MINDSTORMS NXT Components

AT000 - Robotics


4. Sensors & Motors:

Sensors are Inputs for your program or robot, so you can build actions

using the information from the

sensors.

Motors are the outputs of the robot

where the action is applied, depending

on the sensors reading, motor ports,

Sensor Ports & USB port for

downloading programs are shown in

figure 1.22 (a-c).

Ports for Sensors on the NXT brick are

shown in the figure below and

numbered from 1-4.

Fig. 1.22 –a: Motor ports

Fig. 1.22 –b: Sensor ports

Fig. 1.22 –c: USB port – PC.

AT000 - Robotics


Fig. 1.23: Lego MINDSTORMS NXT sensors connected to their default ports.

Motors have three ports since there are three motors for each kit, the Motor

ports are labeled A, B and C as shown in the figure below:

Fig. 1.24: Lego MINDSTORMS NXT Motors connected to ports.

AT000 - Robotics


Learning Task -2

OBJECTIVES: • Write a simple program using NXT program Menu.

• Save and run a program using NXT brick without the use of the

PC.

• Learn how to use the NXT menus: My files and NXT program.

MATERIALS (per group):

• LEGO MINDSTORMS NXT kit:

o NXT Brick.

o 3- Motors.

o 2-Touch Sensors.

o 1- Ultrasonic Sensor.

o 1-Light Sensor.

o 1-Sound Sensor.

o Cables.

Background:

7. My Files

To Open My Files submenu click the orange button of the NXT Brick

Software Files

Programs you have

downloaded from your

computer.

NXT Files

Programs you have

made on the NXT.

Sound Files

Sounds that are part of

a program that you

download.

In the My Files submenu you can store all the programs that you have made on the NXT or downloaded from your computer.

AT000 - Robotics


8. NXT Program

Opening the NXT program will provide you with the default connections

for the Motors & the Sensors as shown in the figure below:

Port 1: Touch Sensor Port 2: Sound Sensor Port 3: Light Sensor Port 4: Ultrasonic Sensor Port B/C: L/R motors

You can start building your program by clicking the orange button

again; NXT program will show you the list of actions you could use to

write a program, the figure below shows the screen of the NXT brick.

You don’t need a computer to program a robot. Using the NXT Program submenu, you can make many programs without your computer.

AT000 - Robotics


Task 1:

a) Using My files Menu go to sound files and run the following files:

a. GoodMorning

b. Have a nice day.

c. Good Job b) Using My files Menu open NXT files and see the files saved,

mention the name of two files:

a. ……………………………

b. ……………………………

c) Open the Software files submenu, do you have any files saved? If

there is no files why?

…………………………………………………………………………………………………… ……………………………………………………………………………………………………

Task 2:

a) Open the NXT Program Menu and do the following:

a. Program Description: program the robot to go back and

forth when the Touch Sensor is pressed.

i. First, the robot will move forward until the Touch

Sensor is pressed, and then it will move backwards.

ii. When its Touch Sensor is pressed again, the robot

will move forward once again. This will continue

indefinitely until you stop the program. b. From the description above a touch sensor in addition to

motors will be needed.

NOTE: when writing a program with NXT Brick, connect the

sensors and Motors to their default ports as described in the

previous page.

i. Connect motors to C & B.

ii. Connect the Touch Sensor to port 1.

c. Follow the procedure in the figure below:

AT000 - Robotics


d. After running the program, describe the motors action when

you press the touch sensor.

…………………………………………………………………………………………………

………………………………………………………………………………………………

e. Click the orange button whenever you want to stop your

program.

f. Save your program using the save icon shown in the figure

below

Save Icon

g. Go back to My Files Menu:

i. Select NXT files subfolder.

ii. Run your program.

Task 3: Follow the procedure in Task-2 to build the following programs and run them:

a) Program1:

a. Connect the sound sensor to port 2 and the motors to ports

C and B. b. Run your program.

AT000 - Robotics


c. Describe what is the program doing with sound sensor and

motors?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

d. What is the effect of sound on the motors movement?

……………………………………………………………………………………………………………………………………………………………………………………………………

e. Stop your program.

b) Program 2:

a. Connect the sound sensor to port 2 and the motors to ports

C and B. b. Run your program. c. Describe what is the program doing with sound sensor and

motors? …………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

d. What is the effect of sound on the motors movement?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

e. Stop your program.

Documents

Robotics - Quia · AT000 - Robotics Module 1: Introduction to Robotics 3 Module 1: Introduction to Robotics Module Objectives 1. Introduce robots to students. 2