App Inventor Arduino

Send a message from smartphone to Arduino

07-05-21 821

Purpose of this tutorial:

In this tutorial we will see how to send a message from the smarthpone to the Arduino board via bluetooth.

We will create two programs: a mobile application with App Inventor for the smartphone and a program for the Arduino board.

Necessary components

Arduino
Smartphone
HC-06 Bluetooth
Display LCD

For the assembly you can see this article:

https://www.robotique.tech/robotics/connect-arduino-to-smartphone-via-bluetooth/

Program

Here is the program which allows you to connect the Arduino board to the smartphone and to receive messages by bluetooth.

The following is displayed on the LCD display:

The word ‘connects’ if the Micro: bit card is connected to the smartphone and the letter ‘disconnects’ otherwise.
The message received from the smartphone

#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);
SoftwareSerial hc06(2,3);
String message="";

void setup(){
lcd.init(); 
//Initialize Serial Monitor
//Initialize Bluetooth Serial Port
hc06.begin(9600);
}

void loop(){
lcd.backlight(); 
lcd.setCursor(0, 0); 
//Write data from HC06 to Serial Monitor
if (hc06.available()){
message+=char(hc06.read());
lcd.clear();
lcd.print(message); //Display the message in the LCD display}
else message="";
}

#include <SoftwareSerial.h>

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);

SoftwareSerial hc06(2,3);

String message="";

void setup(){

lcd.init();

//Initialize Serial Monitor

//Initialize Bluetooth Serial Port

hc06.begin(9600);

}

void loop(){

lcd.backlight();

lcd.setCursor(0, 0);

//Write data from HC06 to Serial Monitor

if (hc06.available()){

message+=char(hc06.read());

lcd.clear();

lcd.print(message); //Display the message in the LCD display}

else message="";

}

Creation of the application with App Inventor:

We create a mobile application named ‘send_microbit’ with App Inventor which allows you to send a message from the smartphone to the Arduino board.

We propose to design the application, with the following visual:

Programming with App Inventor

To program the application, App Inventor offers us to use the Blocks space, which allows you to create a program in the form of a block diagram. Very easy to use but requiring a little programming logic.

Here is the program of the application created in the Blocks area of the Inventor App: