STEM Wonders GRADE 8

03 Stem Activities STEM Wonders

From your data, what launch angle should you use to achieve the greatest distance
from the launch site? Test your conclusion.

Why didn’t the instructions ask you to test for 0 and 90 degrees?

3.2 Creating an Electromagnet
3.2.1 Objective

You will be able to investigate ways to change the strength of an electromagnet
and relate that an electric current creates a magnetic field in this activity.

FUN FACT

Even if you split magnets in half, they
always have two poles.

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03 Stem Activities STEM Wonders

3.2.2 Introduction

When we break down the word electromagnet, the first part, electro, sounds like
electricity. The magnet part of the word is exactly what it sounds like—a magnet!
So an electromagnet is a magnet produced by electricity.
Today, the most important thing to remember is that electricity can generate a
magnetic field. This may seem strange because we are familiar to magnetic fields
originating solely from magnets, but it is true! A
magnetic field is created when an electrical current flows through a wire. In fact,
the most basic
electromagnet is a single coiled wire with an
electric current flowing through it. The mag-
netic field produced by the wire coil is sim-
ilar to that of a regular bar magnet. We can
create a magnetic field by passing an iron (or Fig 3.2.1
nickel, cobalt, etc.) rod (perhaps a nail) through the centre of the coil (see Figure
3.2.1).
We can strengthen this magnetic field by increasing the amount of electric cur-
rent flowing through the wire or by increasing the number of wire wraps in the
electromagnet coil. What do you think will happen if we do both of these? That’s
correct! Our magnet will be even more powerful!

3.2.3 Materials

> D-cell Battery
> Bolt
> Rubber Bands
> Copper Wire
> Paper Clip
> Paper

3.2.4 Instructions

1. Determine the battery’s positive and negative terminals.
2. Wrap the wire at least 20 times around a nail. Make sure the nails are tightly
wrapped, with no gaps between the wires and no overlap.
3. Using the rubber band to keep the wires in place, attach the ends of the coiled
wire to either end of the battery.

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03 Stem Activities STEM Wonders

4. See how many paperclips the magnetic can pick up to test its strength.
5. Record the number of paperclips in the observation.
6. After testing the electromagnet, disconnect the cable from the battery. When
the power is turned off, can the electromagnet pull up paperclips?
7. Test different materials and fill out tables in observation area.

3.2.5 Observations

1. Describe what happens if you hold a nail or paper clip near the coil.

2. How did you test the strength of your electromagnet?

3. Can your electromagnet pick up paper clips when the current is disconnected?

4. Fill out the table by testing different materials.

Materials Electromagnet
Bolt Yes

Pencil

Rubber

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03 Stem Activities STEM Wonders

3.3 Binary Bracelets

3.3.1 Objective

This activity will introduce students to the binary number system. When learning
binary, students will have the opportunity to write codes and share them with
peers. This can then be related back to how computers read a program, translate
it to binary, use the information in some way, then reply back in a way humans can
understand.

3.3.2 Introduction

We are often used to representing numbers using ten
digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. This is called a
base-10, or decimal system. Binary code, however, uses
only zeros and ones in a sequence of eight spots. We
often to refer to these binary, or base-2, digits as
“bits.” Binary code is used to communicate information
between computers, communication devices, and many
more modern technologies. It’s useful to build into elec-
tronic devices because it is a simple system that requires something turn on or
off (where 1 is the on state and 0 is the off state). This activity will allow you to
embed your own name or nickname in this secret code on a bracelet.

3.3.3 Materials 3.3.4 Instructions

> Binary Beads (Black 1. Measure the string and cut around 15 cm of
> and White) it.
> Scissor Select the beads.
> Elastic Thread Black Beads are 0s.
> Pencil White Beads are 1s
Purple Beads are used for spaces.
3. Spell out your name on paper.
4. Use the key to write out each letter of
your name in decimal number system.
5. Convert the decimal number system in
binary number system by taking LCM by 2 of
the respective numbers. For reference you

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03 Stem Activities STEM Wonders

can look at example (Fig 3.34. )
6. Make each letter into a different colored bead.
Choose one color for the white squares (signifying “1)
and another for the black squares (signifying “0”). You
can put a space between each letter. As a divider, add
a purple bead. Separating markers is a computer science concept.
These are known as “delimiters.” Delimiters are used in many encodings, especially
when the data size is large. Each unit is unique. You don’t need a delimiter to know
when one-character ends and another begins. However, because each character
requires exactly 8 bits, another begins in binary code.
7. Start inserting the beads one by one into the elastic thread.
8. Once you are done inserting the beads, tie the both end of the thread together.
9. Cut off any remaining string, far enough away from the knots so they don’t loos-
en.

3.3.5 Worksheet Decimal to Binary

Character To Decimal

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03 Stem Activities STEM Wonders

Directions: Write your name down the left side of the page, then use the binary
code alphabet to find the code for each letter.

3.4 Moon Phases

3.4.1 Objective

Students will assemble a printable Moon Phases Calendar and Calculator using
their knowledge of the Moon’s phases. The tool can then be used to look up the
Moon’s phase for any day of the year and predict when and where the Moon will be
visible.

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03 Stem Activities STEM Wonders

3.4.2 Introduction

Moon phases are the different levels of illumination we see on the Moon from Earth.
They are caused by the relative positions of the Sun, Moon, and Earth as the Moon
orbits our planet every 29.5 days.
A full lunar cycle begins with a new moon and continues through seven distinct
phases before returning to the new moon phase. The Moon is between the Sun and
the Earth during the new moon phase. We can’t see it because the side facing Earth
isn’t illuminated by the sun and it’s so bright outside.
As the Moon orbits Earth, the side facing Earth becomes more illuminated as it
goes through its phases. Viewers will
notice, in order of
appearance:

1. New moon
2. Waxing crescent
3. First quarter
4. Waxing gibbous
5. Full moon
6. Waning gibbous

3.4.3 Material Fig 3. 4.1

> Scissor
> Tape
> Pencil
> Moon Phases Calendar
& Calculator Template

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03 Stem Activities STEM Wonders

3.4.4 Instruction

1. Before cutting anything out, students should use their knowledge of the Moon to
shade in the phases on the Moon Phases Wheel according to the labels.

Fig 3. 4.2

2. The Moon Phases Wheel, Moonset and Moonrise Panels, and Viewing Wheel will
then be cut out as indicated on the back.

Fig 3. 4.3

3. On the Viewing Wheel, you should cut a hole for the “view from space.”

Fig 3. 44.

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03 Stem Activities STEM Wonders

4. Students will attach the Moonset and Moonrise Panels to the Viewing Wheel
where indicated on the back using tape.

Fig 3. 4.5

5. You will use a pencil to make a guide hole in the centre of all three wheels.

Fig 3. 4.6

6.The Moon Phases Calendar and Calculator should then be assembled by placing
the Moon Phases Wheel on top of the Calendar Wheel, followed by the Viewing
Wheel on top of that. They should connect all three wheels in the centre with the

brass fastener (or another fastener).

Fig 3. 4.7

7. Now use your calendars to determine the phase, rise time, and set time for a
specific date.

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03 Stem Activities STEM Wonders

You should identify the moon phase that will be visible on the selected date using the
Calendar Wheel. Students should then spin the Moon Phases Wheel until the moon
phase they identified on the Calendar Wheel is matched. To align the two match-
ing phases, use the “view on Earth” pointer. (Please keep in mind that the Calendar
Wheel displays the dates when moon phases occur in the Pacific Time Zone.)

8. Then, on the viewing window, centre these matched phases above the “S.”
The time shown is when that phase is visible when facing south. That phase
rises in the eastern sky at the time shown in the window by the “E” and sets in
the western sky at the time shown in the window by the “W.”

9. Select a date for which you want to know what moon phase will be visible,
and then repeat the process to determine the moonrise and moonset times.
Then find the same information for a later date. Next, predict the phase, as
well as the moonrise and moonset times, for a date several days later.

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MOON PHASES

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MOON PHASES

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MOON PHASES

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MOON PHASES

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MOON PHASES

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MOON PHASES

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Contents STEM Wonders

0 4S e ct i o n

Robotics

Students will learn :

1. What is Robotics?
2. What is a Robot?
3. Nimble Bot
4. Getting Started with mBlock
5. Project I – LED Blinking
6. Project II – Buzz! Buzz!
7. Project III – Driving Motors
8. Mobile Control Driving
9. Line following robot

08 Robotics STEM Wonders

4.1 What is Robotics?

Robotics is a branch of science, engineering, and technology dealing with the
creation, construction, and operation of machines (Robots). The goal of robotics is
to develop intelligent devices that can help people in several ways.

The branch of technology deals with the design, construction,
operation, and application of robots.

4.2 What is a Robot?

A robot is an output of the robotics industry, A machine resembles
which involves the creation of programmable a human being and is
machines that can help people or replicate their able to replicate certain
actions. human movements and
functions automatically.
Each robot has a different amount of control,
ranging from human-controlled bots that conduct
tasks that a human has complete control over to
fully autonomous bots that accomplish tasks
without any external influences.

4.2.1 Types of Robots?

Robots come in various types from all shapes and

sizes to perform the tasks they are designed for.

Following are some common types of robots:

• Programmable Robots, • Industrials Robots,
• Humanoid Robots,
• Autonomous Robots, • Exoskeletons,

• Drones, etc. Fig 4.1- Edison Programmable Robot

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Fig 4.3- Industrial Robot

Fig 4.2- Exoskeleton Robot

Fig 4.4- Drones Fig 4.5- Humanoid Robots

4.2.2 What are Robots made of? Control System – The Brain
Control systems assist in controlling the
• Control system – The Brain robot’s motions and functions. Control
• Sensors – Inputs systems are built to teach a robot how
• Actuators – Outputs to use its parts, like how the human
• Power Supply – The Electric Juice brain transmits signals throughout the
• End Effectors – The Hands body to achieve a given task. Different
microcontrollers can be used as control
systems like Arduino, Raspberry Pi, etc.

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Sensors – Inputs

A sensor is used to measure the condition of the robot and its surrounding
environment. Sensors provide a robot with stimuli in the form of electrical signals
that are processed by the controller and allow the robot to interact with the
outside world. Some common sensors are photoresistors that react to light, an
ultrasonic sensor that measures the distance of obstacles, etc.

Actuators – Outputs

Actuators are the components that control the movement of robots. These parts
are made up of motors that receive commands from the control system and work
together to carry out the movements required to perform the task.

Power Supply – The Electric Juice

For the robot to work, energy is required. Power supplies provide robots with
sufficient electrical energy for smooth operation. Depending on the type of robot,
electric requirements may vary. For example, some robots need AC power, others
can simply run on a 12V DC battery.

End Effectors – The Hands

An end effector is a device that connects to a robot’s wrist and allows it to engage
with its job. Most end effectors are mechanical or electromechanical and function
as grippers, process tools, or sensors. Interchangeable equipment, such as paint
sprayers and drills, is commonly used by factory robots. Other types of robots can
be designed with gripping claws or even hands for duties such as delivery, packing,
bomb diffusion, and much more.

4.3 Nimble Bot

Nimble Bot is a Programmable Robot designed Fig 4.6- Nimble Bot
especially for school-going kids to learn robotics
by TechTree.io. Using Arduino as its brain,
Nimble Shield for hardware integration and
different sensors.

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Students can learn a lot of activities
such as Blinking a LED and Buzzer, how
to monitor current light intensity, and
programming a Light Controlled Smart
Car.
Now let us look for the components
required to assemble the Nimble Bot.

4.3.1 Arduino

What is Arduino? Fig 4.7- Nimble Components
Fig 4.8- Arduino UNO
An Arduino is defined as a small portable
computer, consisting of a digital brain
that is known as a microcontroller in the
world of electronics. Arduino has the
capability of taking in inputs, i.e.,
interacting with the real physical world and
interpreting the received information to
control various outputs.

A microcontroller is a small tiny computer
contained in a single chip. You can instruct
your Arduino board to perform any task by
sending a set of instructions to it.

Exploring the Arduino UNO

Fig 4.9- Arduino UNO labelled Diagram

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What is Input?

Arduino has senses just like other species in this world. Input is the senses
for Arduino. They tell what is going on in the world. At its most basic, an in-
put could be a switch, such as a light switch in your home. At the other end of
the spectrum, it could be a gyroscope, telling Arduino the exact direction it’s
facing in three dimensions.

What is Output?

The output allows Arduino to affect the real world in some way. An output
could be subtle and discreet, such as in the vibration of a cellphone, or it could
be a huge visual display on the side of a building that can be seen for miles
around. The first sketch walks you through blinking an LED. From there, you can
go on to build your very own smart robotic car.
Here’s a bit of explanation of what each component of Arduino UNO does:

Digital I/O Fig 4.10- Digital I/O

• An Arduino has 14 digital pins. The
digital pins on an Arduino board can
be used for general-purpose input
and output.

• Digital I/O pins on the Arduino allow you to connect the sensors, actuators, and
other components to the Arduino. These pins allow us to read the inputs coming
from a switch, lighting indicators, and controlling relay outputs.

• These pins have two distinct values; HIGH (1) and LOW (0). You use these pins in
a situation where the input or the output value will only have two possibilities; ei-
ther 1 or 0. For example, one way that you might use a digital pin is to turn an LED
on which is 1 (HIGH), or turn it off which is 0 (LOW).

Analog I/O Fig 4.11- Analog I/O
• An Arduino has 6 analog pins which can also be used as
analog pins.

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• The signals from sensors that measure surrounding natural factors such as
temperature, or pressure, are often analog. On the other hand, only digital signals
can be handled by computers. For this reason, analog I/O pins are used. They
allow you to read analog signals.

• These pins have a wide range of values.
• An analog signal can only be read using Analog I/O pins, but you can read digital
signals using both Analog I/O and Digital I/O pins.

Power Pins

• Vin - is the Voltage In pin. The input
voltage to the Arduino board can be used
for powering up the Arduino.

• 5 Volt Power Pin - This power can be Fig 4.12- Power Pins
utilized to power up the components that
require 5 voltages to operate.

• 3.3 Volt Power In - This power pin can be utilized to power up the components
that require 3.3 voltages to operate.

• GND - is the Ground pin that refers to the negative voltages.

Microcontroller Chip – Digital Brain

At the heart of Arduino lies a microcontroller chip (ATMEGA328P in the case
of Arduino UNO). These chips are a digital brain that makes them smart enough
to decide according to their surroundings.

Fig 4.13- Atmega328P SMD version Fig 4.14- Atmega328P Dip version

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Reset Button

In electronics and technology, a reset
button is a button that can reset the
device. In Arduino UNO, the reset button
restarts the code or program from the
very beginning of it.

Serial Communication Pins – (Tx, Rx) Fig 4.15- Reset Button

• You can program Arduino to speak through Fig 4.16- Tx and Rx Pins
Serial Communication.
• It is the procedure by which information and
data are sent one after another ‘’bit by bit’’.
• A bit is the fundamental building block of
digital data, consisting of 0 or a 1.
• Sending messages and data back and forth
from Arduino to a computer or even other
hardware and Arduinos.

4.3.2 Nimble Shield by TechTree Fig 4.17- Nimble Shield

TechTree Arduino shield is a modular circuit
board that piggybacks onto Arduino to install
it with extra functionality. All sensors are
integrated into this stackable shield which is
quite easy to plugin when you want to play
with your Smart Robotic Car and plug out
when you want to use Arduino for other
purposes.

TechTree Arduino shield features the functionality of the H-bridge, which is
particularly used for driving the motors. It also provides functionality for the
Sonar sensor, Light sensor, Line following sensor, and Servo motor. It is also
equipped with an indication circuit for the battery level of your Smart Robotic
Car.

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Let’s explore Nimble Shield!

Fig 4.18- Nimble shield labelled diagram

Light Emitting Diode – LED

A light-emitting diode (LED) is a semiconductor device that emits light when
an electric current flows through it. When current passes through an LED, the
electrons recombine with holes emitting light in the process. LEDs allow the
current to flow in the forward direction and block the current in the reverse
direction.
Light-emitting diode (LED) is a widely used standard source of light in
electrical equipment. It has a wide range of applications ranging from your
mobile phone to large advertising billboards. They mostly find applications in
devices that show the time and display different types of data.

Fig 4.19- LED Symbol Fig 4.20- LED

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Buzzer What is LED?

A buzzer or beeper is an audio signaling Tiny electronic component that glows
device, which may be mechanical, vividly if wired up correctly. The polarity
electromechanical, or piezoelectric of an LED can be determined just by
(piezo for short). Typical uses of buzzers looking at it keenly. LED has two legs;
and beepers include alarm devices, timers, one of them is always shorter in length.
and confirmation of user input such as a The shorter leg serves as the negative
mouse click or keystroke. terminal, and the longer leg of the LED
serves as the positive terminal.

Fig 4.21 -Buzzer What is
Buzzer?

A Buzzer is an electrical device that
produce a buzzing sound. It is typically
used in alarm devices, timers or
confirming the user input such as;
mouse click or keystroke.

Fig 4.22 -Buzzer Symbol

Light Dependent Resistor–LDR

A Light Sensor is a device that converts the light Fig 4.23 -LDR
energy into an electrical signal; understandable to the
Arduino. These devices are commonly known as
“Photoelectric Device” or “Photo Sensor”.

“TechTree Arduino shield is equipped with a light sensor. The most basic compo-
nent
of a Light sensor is the LDR (Light Dependent Resistance). This sensor works on
the principle of photoconductivity. As soon as the light intensity strikes the LDR,
it

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Light-dependent resistors, LDRs, or photoresistors are often used in electronic
circuit designs where it is necessary to detect the presence or the level of light.
When light falls upon it, then the resistance changes. Values of the resistance of
the LDR may change over many orders of magnitude the value of the resistance
falling as the level of light increases.

Fig 4.24- LDR Symbol What is LDR?

LDR is an acronym for Light
Dependent Resistor. It is defined as
a type of resistor whose resistance
depends upon the light striking the
surface. The resistance value
decreases with the increase in the
intensity of light.

DC Motor

DC motors are actuators that convert electrical energy
into mechanical energy. DC motor or Direct Current
Motor, is the most commonly used actuator for producing
continuous movement and whose speed of rotation can
easily be controlled, making them ideal for use in
applications where speed control is required.

Voltage Regulator Fig 4.25- DC motor

A voltage regulator is a system designed to automatically maintain a constant
voltage level. When a steady, reliable voltage is needed, then a voltage regulator
is the preferred device. It generates a fixed output voltage that remains constant
for any changes in an input voltage or load condition.

“Voltage regulators are specifically used in electronic circuitries to maintain the
required amount of voltage for our application. In our scenario, we are using a
battery of 11.5 volts for the application of a robotic car, but the required voltage
rating for our TechTree Arduino shield and Arduino is 5 volts. So, to reach the
required voltage rating we are using a voltage regulator in TechTree Arduino shield.”

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Motor Driver – H-Bridge

Motor Driver, as the name says is used for driving the motors either in clockwise
(CW) or counter-clockwise (CCW) directions. These are H-bridge chips designed
specifically to control the directions and speed of motors. H-bridge is the concept
of electronic circuitry which switches the polarity of the voltage applied to motors,
which results in switching the direction of motors.

“Smart Robotic car consists of two motors; motor right & motor left. To control
the direction and speed of motors, we are using a motor driver which eradicates
the complexity of switching the wires to switch the direction of motors. It simply
transmits LOW & HIGH signals according to the condition set in the programming.”

Battery Indicator

Smart Robotic Car runs on a power source which we call a battery bank. This bat-
tery bank is rechargeable.
“TechTree Arduino shield is equipped with a battery indicator which keeps tracing
the battery level. Red LED will light up when the battery level gets low. At this
point, you need to charge your battery.”

4.4 Getting Started with mBlock
4.4.1 mBlock Installation

• STEP 1: Visit the following links to download the software file.
For Windows 7+: https://dl.makeblock.com/mblock3/mBlock_win_V3 .4 .12.exe
For Win XP: https://download.makeblock.com/mblock/v_3_4_2/mBlock_win_V3.4.2_beta2_20161111.exe
For Mac: https://dl.makeblock.com/mblock3/mBlock_mac_V3.4.12.zip
For Chromebook: https://chrome.google.com/webstore/detail/mblock/cikipehcmeblohaibidanjaelilmdilo

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• STEP 2: Install mBlock
For Windows
1 Double-click the installation file and follow the installation wizard.

1

Fig 4.26 2

Fig 4.27
3

4

Fig 4.28 Fig 4.29

5 2 Click “Allow access”. After the
installation is complete, the mBlock 5
icon is displayed on the desktop.

Fig 4.30

Fig 4.31

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For macOS

1 Open the installation file and follow the installation wizard.

2 After the installation is complete,
the mBlock 5 icon is displayed on the
Launchpad and taskbar in the upper
right corner.

Fig 4.32 Fig 4.33

For ChromeOS
1. Search “mBlock” in the chrome web
store then click Add to Chrome

2. Click “Add app” and wait for the
installation to complete.

Fig 4.35

Fig 4.34

4.4.2 Adding Nimble Extension to mBlock

1. Open mBlock software. This screen will appear.
(Fig 8.35)

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2.Select “Broads” as “Arduino UNO” (Fig 8.36)
3. Click “Extension” and select “Manage
Extensions” (Fig 8.37)
4. Type “Nimble” in the search box, then click
Download. (Fig 8.38)

Fig 4.36

Fig 4.38 Fig 4.37

4.4.3 Uploading Code to Nimble Bot

Step I: Select “Arduino Mode” mBlock

Step II: Connect Nimble Bot with the USB
cable to your computer.

Fig 4.39

Fig 4.40 Fig 4.41

Step III: Select the proper Serial Port
in mBlock. Do this every time you
program the robot.

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Step IV: Now click “Upload to Arduino”
and wait for the robot to program.

Fig 4.42

4.5 Project I – LED Blinking

Blinking LEDs is the simplest project ever - it’s as simple as turning a light on
and off. It always serves as an important stepping stone toward more complex
experiments.

Turning LED ON: Let’s Put the Block Together

Fig4.43

Turning LED OFF:

Fig 4.44 A forever loop can be Fig 4.45
infinite
86 This project comprises turning the LED
Like the sunrise and on and off repeatedly. Lots of programs
the sunset have repetition involved in them, where
a certain part of the code is being used
over and over again.

The computer is efficient in terms of
performing repetition. If you want to
blink the LED infinite times, then what do
you do? Do you write infinite code?
Of course, not, that’s not practically
possible.

04 Robotics STEM Wonders

There’s an easy and efficient way in which you can get the computer to
repeat a certain set of code whatever number of times you want. This
method is called looping.

Wait block is used to put delay so that we can control the blinking speed.

One blink consists of LED being ON half the time and OFF half the time.
Lets assume we want to blink LED one time every two second.

wait = blink time (seconds) / number of blinks x 2
So, wait=2/1 x 2 seconds=1 seconds

4.6 Project II – Buzz! Buzz!

In this project, we will be using a piezo buzzer that makes a small “click” when you
apply a voltage to it (try it!). By itself, that isn’t exciting, but if you turn the
voltage on and off hundreds of times a second, the piezo buzzer will produce a
tone. Let’s get to make a tone.

Buzzer ON Let’s Put the Block Together

Fig 4.46 Fig 4.48

Buzzer OFF

Fig 4.47

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What’s happening in the code?

We are using a forever loop, which is an infinite loop, because
we want the buzzer to beep continuously. For the buzzer to
buzz in repetition, it should remain on for certain amount of
time and then goes off and then again on. To achieve this,
initially, the buzzer is set to a HIGH state which means that it
is turned on. We include some time delay by asking the code to
wait for 0.5 seconds before moving on to the next line of the
code. After 0.5 seconds, the buzzer state is changed to LOW,
which means that it is turned off. It remains off for a period of
0.5 seconds. The code is then repeated from the first line in

the loop. You can change the wait time and alternate the
buzzer states as per your wish.

4.7 Project III – Driving Motors

In this project, we will witness the movement of the robot using a DC motor.
Let’s hop on to building the project right away!

The Nimble comes with a pair of DC motors and wheels and each motor has a
two-pin connector that has to be connected to the Arduino shield on the LM and
RM labeling respectively.

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Forward Movement 4.8 Project IV –
Mobile Control Driving
Fig 4.49
How to get Bluetooth connectivity in
Backward Movement Nimble Robot?
Using HC-05. It is a Bluetooth mod-
Fig 4.50 ule!! (Fig 4.53)

Right Movement Fig 4.53

Fig4.51 What is HC-05?

Left Movement HC-05 is a Bluetooth module which
is designed for wireless
Fig 4.52 communication. Bluetooth modules
allow all serial enabled devices to
communicate with each other using
Bluetooth. For example, it can be
used to connect a microcontroller
like Arduino with a Mobile Phone or
Laptop. HC-05 has 6 pins, a status
LED and a reset button.
The module has two working modes:
i. Data Mode
ii. Command Mode

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Pin Pin Name Description
Number
Enable/Key This pin is used to toggle between Data Mode (set
1 LOW) and AT command mode (set HIGH). By default,
2 Vcc it is in Data mode. The default baud rate of HC-05 in
3 Ground command mode is 38400bps and 9600 in data mode.
4 Powers the module. Connect 5 V or 3.3 V to this
5 Pin.
6
Ground pin of module. Connect to system ground.
7
Tx - Transmits Serial Data.
8 Transmitter
Rx - Receive Serial Data.
Receiver
State The state pin is connected to an on-board LED, it
can be used as feedback to check if Bluetooth is
LED working properly.

Button Indicates the status of Module:
> Blink once in 2 sec: Module has entered Command
> Mode.
> Repeated Blinking: Waiting for connection in Data
> Mode.
> Blink twice in 1 sec: Connection successful in Data
> Mode.

Used to control the Key/Enable pin to toggle
between Data and command Mode.

As soon as you turn on the module, you should be able to discover the Bluetooth
device as “HC-05”, connect to it with the default password “1234”, and begin
communicating with it. By switching to Command Mode, you can change the name,
password, and other default values. By using a Mobile application (Bluetooth RC
Controller) this module can be used for controlling the Nimble Bot.

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04 Robotics STEM Wonders

Applications:
1. Wireless communication between two
microcontrollers,
2. Communicate with Laptop, Desktops and
mobile phones,
3. Data Logging application,
4. Consumer applications,
5. Wireless Robots,
6. Home Automation, and many more.

See Fig 4.54 for the code.

Connect Nimble Bot to the Mobile Fig 4.54

Application:

1. Search “Bluetooth RC Controller” on Google

Play Store and install the application.

2. Now open the application, you will be pre-

sented with the shown interface. (Fig 4.55).

3. Now turn ON the Bluetooth of your Mobile

Phone and pair “HC-05”.
3. Now click the “Settings” symbol in the App. Fig 4.55

Click “Connect to car”. (Fig 4.56)

4. Now click the “Settings” symbol in the App.

5. Click “Connect to car”. (Fig 4.56)

6. Select the device from the paired device list.

(Fig 4.57)

7. After the connection is successful the red

blinking indicator will turn Green. (Fig 4.58) Fig 4.56

Fig 4.57

Fig 4.58

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04 Robotics STEM Wonders

4.9 Project V – Line Following Robot

What is a Line Following Robot?
The Line Follower Robot is a simple robot that follows a path given by a line (typically a
black line on a light-colored surface) of a specific width. Line Following Robot uses
multiple IR or Reflective Optical sensors in combination with a Microcontroller.

What is a Reflective Optical Sensor?
TCRT5000 is one the Reflective Optical Sensor. It consists of an Infrared LED, a Pho-
totransistor (Sensitive to light), a Potentiometer to adjust its sensitivity, and four pins.
This sensor has a coating on it that blocks light that is not in the infrared band to help
limit the possibility of environmental interference; this is what gives the sensor its black
color on input side.

Pin Pin Name Description
Number
A0 The analogue pin A0 provides a continuous reading in the
1 form of varying voltage, the higher the voltage the more
infrared light is being received.

2 D0 The digital pin on the other hand is either HIGH
(ON) or LOW (OFF). Not enough light is received
3 Ground this pin will be HIGH. When the trigger level set by
4 Vcc the potentiometer is passed the digital pin is then
set to low.

Ground pin of sensor. Connect to system ground.

Powers the sensor. Connect 5 V or 3.3 V to this

Note: To adjust the trigger level, rotate the potentiometer.

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04 Robotics STEM Wonders

Working:
The TCRT5000 operates by sending infrared light from the IR LED and registering any
reflected light on its Phototransistor, which changes the flow of current between its
emitter and collector based on the amount of light it receives.

Values on white surface:
A0 – Maximum
D0 – LOW

Values on Black surface: Fig 4.59
A0 – Minimum
D0 – HIGH
Cases:

Forward Left Right
See Fig 4.60 for the code.

Fig 4.61 93

End of Section - 04 ROBOTICS

Choose the right one!

1. The type of I/O that can only will represented in two states?
a. Analog.
b. Digital.
c. None of the above.
d. All of the above.

2. Which of the following acts as the brain of the Nimble Bot?
a. TechTree Nimble Shield.
b. Bluetooth Module.
c. TCRT5000.
d. ATMega328P.

3. Which of the following is used to transmit data serially helping you to connect the
Nimble Bot with a Cellphone?
a. TechTree Nimble Shield.
b. Bluetooth Module.
c. TCRT5000.
d. ATMega328P.

4. Which of the following is used to measure the light reflectivity and helps you to
track black or white color?
a. TechTree Nimble Shield.
b. Bluetooth Module.
c. TCRT5000.
d. LDR.

5. Where on the mBlock interface can you read the received data?
a. Workspace.
b. Serial Port.
c. Serial Monitor.
d. None of the above.

94

Answer the following!

1. Define Robotics? Also explain any two types of robots?

2. What is an LED? Explain how can you make an LED blink?

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End of Section - 04 ROBOTICS

3. Explain the purpose of using DC Motors? Also, explain all drive

4. Define Bluetooth module and its uses?

96