I want to manage sensors and actuators connected to Arduino Uno, through a simple smartphone application, using a Bluetooth module, which uses short-range radio waves to put two neighboring devices are communicating. A hand for programming mobile apps is given to us by App Inventor, a development environment with a graphical interface, simple and intuitive for those who already know the world of coding programming. To practice with App Inventor and Arduino programming, I refer you to the respective websites and reference guides.
Exercise 1
Basic application that allows you to turn on LED 13 on the Arduino board from your mobile phone.
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Remember that before connecting to Arduino with Bluetooth, using the app you just created with App Inventor, you must pair the Bluetooth of your mobile phone with the HC-05 board. To do this, first go to your mobile phone settings and find your HC-05 card in the list of detected devices, then pair it with password 1234.
Here the material to develop the application: PDF step by step , Arduino sketch, App Inventor AIA.
Exercise 2
Here I briefly show you an application that allows you to turn on LED 13 on the Arduino board from your mobile phone and at the same time receive a byte (an integer between 0 and 255) acquired by an Arduino analog pin on your smartphone. The analog inputs of Arduino are 10 bits (between 0 and 1024) but it is possible to compress the acquisition on 8 bits in order to divide the acquired value by 4.
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In this Arduino sketch I use SoftwareSerial library that allow serial communication on other digital pins of the Arduino, rather than pins 0 and 1 (which also go to the computer via the USB connection).
Here the material to develop the application: PDF step by step , Arduino sketch, App Inventor AIA.
Exercise 3
Like Exercise 2, with the only difference that now the mobile phone receives an integer between 0 and 1023 acquired from an Arduino analog pin. Now the app on your smartphone not only reads one byte at a time sent to it by Arduino, but all the bytes that are sent to it.
Here the material to develop the application: PDF step by step , Arduino sketch, App Inventor AIA.