In this tutorial, we will control a small fan by bluetooth using the Arduino board and a smartphone.This is why we will create two programs: a mobile application with App Inventor for the smartphone and a program for the Arduino board.
To carry out the assembly, you can connect:
pin (S) to digital pin 4 of Arduino
pin (-) to GND pin of Arduino
pin (+) to 3.3V pin of Arduino
(ON) pin to 5V pin of Arduino
the first terminal to the COM pin of the relay
the second terminal to the GND pin of the Arduino
the GND pin to GND of Arduino
the VCC pin to the 5V pin of Arduino
the RXD pin to the digital pin 3 of Arduino
the TXD pin to the digital pin 2 of Arduino
Here is the program that allows you to connect the Arduino board to the smartphone and receive a message containing the order to start or stop the fan.
//Initialize Serial Monitor
//Initialize Bluetooth Serial Port
//Read data from HC06
//Select function with cmd
Serial.print("Command recieved : ");
// We expect ON or OFF from bluetooth
digitalWrite(4,HIGH);//Start the fan
Serial.println("Function is on");
digitalWrite(4,LOW);//Stop the fan
Serial.println("Function is off");
Serial.println("Function is off by default");
cmd=""; //reset cmd
We are going to create a mobile application named ‘start_ventilateur_arduino’ with App Inventor which allows remote control of the fan.
We propose to create the design of the application, with the following visual:
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: