Arduino bt mobile robot r2.0

Arduino Bluetooth Mobile Robot
“Controlling Your Arduino Mobile Robot Using Android Bluetooth App”
Cytron Technologies Sdn Bhd - https://www.cytron.io
Version 2.0
...for dummy

Arduino Bluetooth Mobile Robot Module Content
Arduino Bluetooth Mobile Robot by Cytron Technologies - https://www.cytron.io
No TOPIC DURATION
1. Mobile Robot Introduction 10 minutes
2. Getting Started with Maker UNO 30 minutes
3. Assemble the Mobile Robot 1 hour
4. Control the DC Motor 10 minutes
5. Set the Robot Movement 20 minutes
6. Serial Communication 20 minutes
7. Bluetooth HC-05 AT Command 10 minutes
8. Arduino BT Joystick Android App 20 minutes
9. Arduino Bluetooth Mobile Robot Let’s Play! 30 minutes

Mobile Robot Introduction
What is Mobile Robot?
Robots that can move around in a physical environment. Mobile robots are generally
controlled by software and use sensors and other gear to identify their surroundings.
In general, we can divide mobile robot into
● Autonomous
○ Robot moves automatically based on the sensors and other gear.
● Manual
○ Robot moves depend on the command received from the instructor.
Basic thing to develop mobile robot
1. Robot chassis.
2. Motor, motor driver and wheels.
3. Controller.
4. Battery.

Mobile Robot Introduction
List of mobile robot parts for this workshop
Quantity Description
1 set 2WD Smart Robot Car Chassis
1 Maker UNO (Arduino Uno compatible)
1 L298N Dual H Bridge Motor/Stepper Driver
1 set Male to Female Jumper Wire
1 set Male to Male Jumper Wire
4 PCB Stand
1 sets 4 x AA Battery
1 Bluetooth Serial Transceiver HC-05

Getting Started with Maker UNO
What is Maker UNO?
Maker UNO is an Arduino Uno compatible board which is specially designed for
those who interested in learning electronic and programming for the first time.
What is ?
Arduino is an open-source electronics
prototyping platform based on flexible,
easy-to-use hardware and software. It’s
intended for artists, designers,
hobbyists, and anyone interested in
creating interactive objects or
environments.

On-board Piezo Buzzer
Piezo buzzer is connected to
pin 8 through slide switch.
On-board Programmable
Push Button
This button is connected to pin
2 without a pull up.
Reset Button
Press to restart program.
Mini Slide Switch
Switch to connect/disconnect
piezo buzzer to pin 8.
USB Micro B Connector
Main supply, program and
debug purpose.
On-board Series of LEDs
All digital pins is equipped with
LED. This LED can be controlled
or act as signal indicator.
USB to UART IC
Equipped with CH340G for USB
to UART conversion.
Main Microcontroller
Same as uC inside Arduino Uno
- ATmega328P.
Analog Input Pin
This pin can be used for reading
analog voltage.
Arduino ISP Pin
This pin can be used for SPI and
bootloader programming.
Serial Pin
Hardware Serial (UART) is
labeled with RX and TX pin.
Power Pin
USB 5V, regulated 3.3V 500mA
and GND.

Arduino IDE
Arduino IDE is an open source software and it is free. Maker UNO can be
programmed using Arduino IDE. To get the latest version, you can download at
https://www.arduino.cc/en/Main/Software
Note: For Windows, we recommended to choose Windows Installer.

Menu Bar
Button Bar
Serial
Monitor
Sketch Name
Status Bar
IDE Output
Code Area
Board Name and Port

Verify
Compiles and approves your code. It will detect errors in syntax (e.g. missing semi colon
or parentheses).
Upload
Compiles and send your code to the Maker UNO. When you click it, you should see the
lights (labelled RX & TX) on your board blink rapidly.
New Sketch
This button opens up a new code window tab.
Open
This button will let you open an existing sketch.
Save
This saves the currently active sketch.
Serial Monitor
Open Serial Monitor.

Maker UNO Driver
In order to make your Maker UNO board can be detected by PC/laptop, you need to
install CH340G driver. Download the driver from the following link.
● Windows - https://cdn.cytron.io/makeruno/CH341SER.EXE
● Mac - http://www.wch.cn/download/CH341SER_MAC_ZIP.html
● Linux - Normally is readily installed

Assemble the Mobile Robot

Wiring and connection

Wiring and connection
Maker UNO Pin Connection Maker UNO Pin Connection
0 NC 10 Motor Driver IN3
1 NC 11 Motor Driver IN4
2 Internal Push Button 12 NC
3 Bluetooth Transmit 13 NC
4 Bluetooth Receive A0 NC
5 Motor Driver ENA A1 NC
6 Motor Driver ENB A2 NC
7 Motor Driver IN1 A3 NC
8 Internal Buzzer A4 NC
9 Motor Driver IN2 A5 NC

Control the DC Motor
What is DC Motor?
Any of a class of rotary electrical machines that converts direct current electrical
energy into mechanical energy. There have 2 types if DC motor:
1. Brush
2. Brushless
How brush DC motor works?

#define BUTTON 2
#define L298N_ENA 5
#define L298N_ENB 6
#define L298N_IN1 7
#define L298N_IN2 9
#define L298N_IN3 10
void setup()
{
pinMode(BUTTON, INPUT_PULLUP);
pinMode(L298N_ENA, OUTPUT);
pinMode(L298N_ENB, OUTPUT);
pinMode(L298N_IN1, OUTPUT);
}
Define pin 2 as internal push button.
Define pin 5 as motor driver ENA.
Define pin 6 as motor driver ENB.
Define pin 7 as motor driver IN1.
Set push button as input with internal pull up.
Set motor driver ENA as output.
Set motor driver ENB as output.
Set motor driver IN1 as output.
Moving DC Motor: Write and Upload this code to your Maker UNO.

void loop()
{
if (digitalRead(BUTTON) == LOW) {
digitalWrite(L298N_ENA, HIGH);
digitalWrite(L298N_IN1, HIGH);
digitalWrite(L298N_IN2, LOW);
digitalWrite(L298N_ENB, HIGH);
}
else {
digitalWrite(L298N_ENA, LOW);
digitalWrite(L298N_ENB, LOW);
}
}
If button is pressed, move the motor.
Enable channel A
Set the direction for motor 1
Enable channel B
If not pressed, both motors will stop
Disable channel A
Disable channel B
Moving DC Motor: Write and Upload this code to your Maker UNO.

Result:
When the push button is pressed, both motors will move to certain direction. So
how to change the motor direction?
This table shows the relationship between driver signal at channel A and motor 1
direction. Same applies to channel B and motor 2.
Motor 1 ENA IN1 IN2
Stop LOW Don’t care Don’t care
Clockwise HIGH LOW HIGH
Counter Clockwise HIGH HIGH LOW
Brake
HIGH HIGH HIGH
HIGH LOW LOW

if (digitalRead(BUTTON) == LOW) {
analogWrite(L298N_ENA, 200);
analogWrite(L298N_ENB, 200);
}
If button is pressed, move the motor.
Set voltage at pin ENA to ~4V (200/255 x 5V)
Set voltage at pin ENB to ~4V (200/255 x 5V)
Controlling Motor Speed: You can control the motor speed by applying different
voltage at enable pin by using analogWrite() function.
For example:

Set the Robot Movement
Basic Mobile Robot Movement
You already know how to control the motor. By combining the movement of both
motors, you can set the robot movement!
Below is the basic movement of the robot:
1. Stop/Brake
2. Forward
3. Reverse
4. Turn Left
5. Turn Right
Note: Everyone will have a different set of program to produce the same
movement. This is because we don’t have the same connection especially on
motor terminal. So find yours!
How to
move?
Which direction
I need to rotate
so my body will
move forward?
???

Robot Movement: FORWARD

Robot Movement: REVERSE

Robot Movement: TURN RIGHT

Robot Movement: TURN LEFT

void robotForward(int robotSpeed)
{
analogWrite(L298N_ENA, robotSpeed);
analogWrite(L298N_ENB, robotSpeed);
}
void robotReverse(int robotSpeed)
{
}
Function for robot move forward, speed = 0 - 255
Enable channel A (Right motor)
Set the direction for motor 1 to move forward
Enable channel B (Left motor)
Function for robot go reverse, speed = 0 - 255
Set the direction for motor 1 to reverse
Create function: Once you have finalize your robot movement, create function for
each movement - forward, reverse, turn right, turn left and stop.

void robotTurnRight(int robotSpeed)
{
}
void robotTurnLeft(int robotSpeed)
{
}
Function for robot turn right, speed = 0 - 255
Set the direction for motor 1 to go reverse
Function for robot turn left, speed = 0 - 255

void robotStop()
{
}
void robotBrake()
{
}
Function for robot stop
Motor 1 stop
Motor 2 stop
Function for robot brake
Motor 1 brake
Motor 2 brake

Serial Communication
What is Serial Communication?
It is a most popular communication protocol (also known as UART) used to
communicate between the Arduino board and a computer or other devices.
● Bluetooth: HC-05, HC-06.
● GSM: SIM900A, SIM800L.
● WiFi module: ESP8266.
● RFid reader: 125kHz, MiFare.
● GPS, RF module, and more...
Hardware Serial
It communicates on digital pins 0 (RX) and 1 (TX) as well as with the computer via
USB. Thus, if you use these functions, you cannot also use pins 0 and 1 for digital
input or output.
Note: Please disconnect pin 0 and 1 during uploading sketch.

Serial Communication
Software Serial
Due to limited number of hardware serial (only at pin 0 and 1) in Arduino Uno,
SoftwareSerial library has been developed to allow serial communication on other
digital pins of the Arduino Uno board.
However, there still have limitation on SoftwareSerial library for Arduino Uno:
● If using multiple software serial ports, only one can receive data at a time.
● Current maximum RX speed is 57600 bps.
● RX doesn't work on pin 13.

Bluetooth HC-05 AT Command
What is AT Command?
AT commands are instructions used to control a modem. AT is the abbreviation of
ATtention. Every command line starts with "AT" or "at", as a prefix that informs the
modem about the start of a command line.
AT Command Description
AT Check the connection.
AT+VERSION Check bluetooth version. For example, it returned VERSION:3.0-20170609
AT+NAME=.... Set bluetooth name. For example AT+NAME=Maker UNO
AT+PSWD="...." Set bluetooth pin number. For example AT+PSWD=”8888”
AT+ORGL Restore factory setting

#include <SoftwareSerial.h>
SoftwareSerial HC05Serial(3, 4);
void setup()
{
Serial.begin(9600);
HC05Serial.begin(38400);
}
void loop()
{
if (Serial.available()) {
HC05Serial.write(Serial.read());
}
if (HC05Serial.available()) {
Serial.write(HC05Serial.read());
}
}
Include SoftwareSerial function
Set pin 3 as RX and 4 as TX
Initialize Serial with 9600bps
Initialize bluetooth serial with 38400bps
If AT command received from Serial Monitor
Send AT command to bluetooth
If response received from bluetooth
Display on Serial Monitor
Upload this sketch to Maker UNO.

Now set your own name and pin number at your bluetooth module. For example:
Send Received
AT OK
AT+VERSION
VERSION:3.0-20170609
OK
AT+NAME=Maker UNO OK
AT+PSWD=”8888” OK

To enter AT command mode in HC-05 bluetooth module, please follow these
steps:
1. Turn off the bluetooth module.
2. Press and hold button on the bluetooth module.
3. Turn on the bluetooth module.
4. Release the button.
Open Serial Monitor and set to
9600 baud and Both NL & CR.
Next, configure bluetooth with
AT command.

Arduino BT Joystick Android App
void setup()
{
Serial.begin(9600);
}
void loop()
{
if (Serial.available()) {
HC05Serial.write(Serial.read());
}
Serial.write(HC05Serial.read());
}
}
If AT command received from Serial Monitor
Send AT command to bluetooth
If response received from bluetooth
Display on Serial Monitor
Upload this sketch to Maker UNO. Then, we can see the status of the button on the
Arduino BT Joystick app at the Serial Monitor when the bluetooth is connected.

In this workshop, we will use Arduino BT Joystick Free. Why? Because it is free,
easy to use and have a nice layout. So let’s install and open it.

FYI, Arduino BT Joystick Free is no longer available in Play Store. But don’t worry,
we have prepared the APK file. You can download here (click using your phone)
from Google Drive.

Finish download, click on the installer (APK) file. By default your phone setting is
not allowed any installation except from Play Store. Unless you’re sure the
sources, you can allow the installation on your phone setting.

Proceed with the installation. Once complete, the app icon will appear on your
phone - home screen. To open it, just tap on the icon as usual.

Now we need to configure a bit on
this app.
1. Click on the Menu and choose
Settings.
1. Click Define the send delay.

3. Update value in Define the send
delay (ms) from 20 to 200. Click
OK and Save.
3. It will return to the main screen.
Now click CONNECT.

5. Choose your bluetooth name.
Make sure your bluetooth name
is unique. Else, other participant
will connect to your bluetooth. :)
5. Put your bluetooth pin number
and click OK.

7. If the connection successful, the
CONNECT button will update to
DISCONNECT. If you click on the
DISCONNECT button, it will
disconnect the bluetooth
connection.
7. Then, if you notice, there have a
set of data display on Serial
Monitor (during bluetooth is
connected). This is the status of
the button on the Arduino BT
Joystick app.

Every 200ms (set in Define the send delay), this app will send a set of data as
shown in the picture above. If no key have been pressed, it sends #b=0#.

char inChar;
String inString;
void setup()
{
Serial.begin(9600);
}
Global char variable for inChar
Global string variable called inString
After knowing the data set, now we need to grab the data and do comparison in
the program, so that we can make specific action for specific key.

void loop()
{
delay(100);
inString = "";
while (HC05Serial.available()) {
inChar = HC05Serial.read();
inString = inString + inChar;
}
if (inString == "#b=0#") {
Serial.println("None");
}
else if (inString == "#b=1#") {
Serial.println("Up");
}
}
}
If bluetooth received the data from the app
Wait for 100ms so that all the data is received
Clear inString variable
While the data set is available
Read and store to inChar variable
Combined characters to form a single string
Do comparison, if inString = "#b=0#"
Print on Serial Monitor “None”
Do comparison, if inString = "#b=1#"
Print on Serial Monitor “Up”

Arduino Bluetooth Mobile Robot
This is the final stage to create Arduino Bluetooth Mobile Robot. Make sure the
previous chapters is working.
1. Set the robot movement together
with functions.
2. Configure bluetooth using AT
command (name, pin #).
3. Read data set from the app.
4. Compare and do specific action.
5. Now, combine no 1 and 4.

#define RX 3
#define TX 4
SoftwareSerial HC05Serial(RX, TX);
#define BUTTON 2
#define L298N_ENA 5
#define L298N_ENB 6
#define L298N_IN1 7
#define L298N_IN2 9
char inChar;
String inString;
Define pin 3 as received pin = HC05 TX.
Define pin 4 as transmit pin = HC05 RX.
Define pin 2 as internal push button.
Define pin 5 as motor driver ENA.
Define pin 6 as motor driver ENB.
Global char variable for inChar
Global string variable called inString

void setup()
{
Serial.begin(9600);
pinMode(BUTTON, INPUT_PULLUP);
pinMode(L298N_ENA, OUTPUT);
pinMode(L298N_ENB, OUTPUT);
}
Set push button as input with internal pull up.
Set motor driver ENA as output.
Set motor driver ENB as output.

BT JoysArduino tick Android App
void loop()
{
delay(100);
inString = "";
while (HC05Serial.available()) {
inChar = HC05Serial.read();
inString = inString + inChar;
}
if (inString == "#b=0#") {
robotStop();
} else if (inString == "#b=1#") {
robotForward(200);
robotReverse(200);
robotTurnLeft(150);
robotTurnRight(150);
}
}
}
If bluetooth received the data from the app
Wait for 100ms so that all the data is received
Clear inString variable
While the data set is available
Read and store to inChar variable
Combined characters to form a single string
If inString = "#b=0#"
Robot stop
Robot move forward with PWM 200
Robot go reverse with PWM 200
Robot turn left with PWM 150
Robot turn right with PWM 150

void robotForward(int robotSpeed)
{
}
void robotReverse(int robotSpeed)
{
}
Function for robot move forward, speed = 0 - 255
Function for robot go reverse, speed = 0 - 255

void robotTurnRight(int robotSpeed)
{
}
void robotTurnLeft(int robotSpeed)
{
}
Function for robot turn right, speed = 0 - 255
Set the direction for motor 1 to go reverse
Function for robot turn left, speed = 0 - 255

void robotStop()
{
}
void robotBrake()
{
}
Function for robot stop
Motor 1 stop
Motor 2 stop
Function for robot brake
Motor 1 brake
Motor 2 brake

End of Workshop
Thank you and Let’s Play!
Q & A Session

Arduino bt mobile robot r2.0

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