Difference between revisions of "Arduino/C3/Robot-Control-using-Bluetooth/English"

Learning Objectives

• Bluetooth Communication
• HC-05 Bluetooth Module and
• Controlling a Robot using an Android application

Pre-Requisites

• Electronics and
• C or C++ programming language

System Requirements

• Ubuntu Linux 16.04 OS
• Arduino UNO board
• Arduino IDE and
• Android Phone

External Components

• HC-05 Bluetooth Module
• L293D IC

We have learnt about the L293D Motor Driver IC in the earlier tutorial.

• 9V Battery with Connector
• 9Volts-1Ampere Adapter

Bluetooth Communication

• Bluetooth communication is a wireless technology.
• It is used to transfer data between different electronic devices.
• It supports data, audio transmission with a range of 7 to 8 meters.
• It is specially designed for short range wireless data communication.

• In this tutorial we will use the HC-05 Bluetooth module.
• This module has two operating modes, namely Data Mode and AT Command Mode.
• In Data Mode, it can send and receive data from other Bluetooth devices.
• We will be using the Data Mode in our tutorial.
• AT Command mode is used when you want to change the setting of the Bluetooth module.
• For example, to change the Baud Rate we can use AT Command Mode

We have already installed an app called Car Bluetooth RC on Android phone.

This app will control the movement of the Robot.

Let us see the circuit connection in detail.

Do the actual connection with your hardware as explained here.

Circuit Connection

The 5V pin of the Arduino is connected to the 5V pin of the HC-05 module.

The ground pin of the Arduino is connected to the ground pin of the HC-05 module.

The Rx pin of the Bluetooth module is connected to the Tx pin of Arduino.

The Tx pin of the Bluetooth module is connected to the Rx pin of Arduino.

Now, note the blinking of LED in the Bluetooth module.

This indicates that your Bluetooth module is switched ON.

Circuit Connection

Pin 16 of L293D IC is connected to 5V of Arduino.

Pins 4,5,12,13 of the L293D IC are connected to the ground terminal.

Circuit Connection

Pins 9,10,15 of L293D IC are connected to pins 11,10,9 of Arduino respectively.

Circuit Connection

The other DC motor is connected to pin 11 and 14 of L293D IC.

Note: You have to connect the DC motors of the assembled Robot as shown in figure.

Recall that we have soldered a red and black wire to the wire leads of the motors.

Circuit Connection

We will use a 9V battery to power the DC motors as Arduino gives only 5V output.

Positive terminal of the 9V battery is connected to pin 8 of L293D IC.

The negative terminal of the battery is connected to the ground pin of the Arduino.

These are all the connections you must do to perform the tasks shown in this tutorial.

Live Setup of Robot

This is how I have done the setup of my Robot.

Code Files:

• The files used in this tutorial are available in the Code Files link on this tutorial page.
• Please download and extract them
• Make a copy and then use them while practising

These are the variables assigned for the pins on the Arduino connected to L293D IC.

The variable serialA is used to store the input character received by Bluetooth.

Serial.begin function is used to make the Arduino ready to serially exchange messages.

The messages are exchanged at 9600 baud rate.

We will use the function pinMode to configure the pins to OUTPUT mode.

{

if (Serial.available() > 0)

{

serialA = Serial.read();Serial.println(serialA);

}

switch (serialA)

The void loop function will move the Robot in forward, backward, right and left directions.

Bluetooth module checks for commands given from the Android app.

These lines of code make the robot turn in the left direction.

These lines of code make the robot turn in the right direction.

These lines of code make the robot move in a backward direction.

Our program is ready now.

After compiling, a pop-up window will open to save the current program.

I will save it as Bluetooth_Robot.

Click on the Save button to save the program.

Show the circuit diagram and point to the 2 wires with arrows

Show the circuit diagram and point to the 2 wires with arrows

Now click on the Upload button to upload the current program on Arduino.

When you have successfully uploaded the program reconnect the Rx and Tx wires to the Arduino.

9V-1A adapter image

Arduino jack image

Battery image

For demonstration purpose, I have connected a 9V-1A adapter to run the Robot.

It is connected at the Arduino jack available here.

You can use a power bank or a battery instead, to power the Arduino.

Take the Android phone in which you have downloaded the Car Bluetooth RC app.

Go to the Settings option on your phone.

Open the Bluetooth section.

Turn ON your phone’s Bluetooth.

Search for nearby devices.

You will find HC-05 as one of the options in the list.

Click on the HC-05 option. It will ask for a password.

The default password for this Bluetooth module is 1234. Type the password.

In some cases, the password of the Bluetooth module will be 0000.

Image of the connected circuit

Turn OFF Bluetooth on the phone

You can now observe a different blinking pattern of the LED in the Bluetooth module.

Turn OFF your phone’s Bluetooth.

The app will prompt to turn ON your phone’s Bluetooth.

Click on Allow to Continue.

On the top left corner of your phone, click on the arrow.

Find the HC-05 option and click on it.

You can see a message as Connected-OK.

It indicates that your phone is now connected to the HC-05 Bluetooth Module.

Now, it is ready to control the Robot.

Press Forward button

Press Backward button

When I press the forward button in the app, we can see the Robot moves in the forward direction.

When I press the backward button, the Robot moves in the backward direction.

Press Right button

The right side motor stops rotating and the left side motor continues to rotate.

This way the Robot turns to the right side.

Thus, we can control the movement of the Robot using bBluetooth communication.

Summary

• Bluetooth Communication
• HC-05 Bluetooth Module
• Controlling a Robot using an Android application

About Spoken Tutorial project

Please download and watch it.

Spoken Tutorial workshops

For more details, please write to us.

Forum for specific questions

Acknowledgement

And this is Saurabh signing off.

Thanks for watching.