seiot-22-23-android-lab

Code for the labs of the academic year 2022/23 Embedded Systems and IoT course in the Computer Science and Engineering Bachelor Degree of University of Bologna.

Structure of the repository

Inside this repository you will find several simple example of android applications to learn the basic concepts of the Android system plus a full example of an android app that connects to arduino to turn a led on and off.

• AndroidExample00 Is a basic example of an Hello World and shows the lifecycle of an Activity.

• AndroidExample01 Shows examples of how activities can be called from one another.

• AndroidExample02 Shows an example of how to use multiple threads on the same application.

• AndroidExample03 Is an example of doing HTTP requests to download an image from the internet.

• AndroidExample04 Uses several built-in sensors to sample data and display them on screen.

• RemoteBlinkApp Is a project configured to use bluetooth to connect to Arduino and turn a led on and off.

• arduino is a folder containing utils and examples on how to use the bluetooth module.

• emulator-serial-adapter is a Java app that allow the Android emulator to connect using a WebSocket on the host machine and send message to arduino using the USB Serial.

How to use RemoteBlinkApp

There are two ways you can use the RemoteBlinkApp:

• with an android device that has bluetooth capabilities
• with the Android Studio emulator

Use app with Android device

1. Connect the Bluetooth module to Arduino. Please check that you connected the wires correctly on the RX and TX pins. TX of Arduino needs to be connected to RX on the bluetooth module and vice-versa.
2. Setup your AT module using the AT mode util
3. Load the code on Arduino:
   • bt-remote-blinking shows how to read directly from the bluetooth serial.
   • bt-remote-blinking-msg uses a MessageService class that encapsulate the use of serial communication. This is useful to use both the serial and the bluetooth at the same time. Check the `readSerialMessage(bool useBluetooth, bool useSerial) to understand the behaviour of this class and how to use it.
4. Install the RemoteBlinkApp on your Android Device.
5. Turn Bluetooth On.
6. Follow the steps on the app:
   • Scan for devices
   • Click on the AT module to establish connection
   • The LedSwitchActivity will open check the code in here to extend it for your assignments.
   • You should be able to turn the led on and off

Use app with Android emulator on AndroidStudio

1. Connect Arduino to the USB serial, you won't need the bluetooth module for this.
2. Load the code on Arduino:
   • emu-remote-blinking shows how to connect to read from the serial faking the existence of two separate channels by using a special character ($) to discriminate the source of the message. Check the `readSerialMessage(bool useBluetooth, bool useSerial) to understand the behaviour of this class and how to use it and note how it's different from the Bluetooth implementation.
3. Start the emulator-serial-adapter this will open a socket on your local machine that will wait for messages and redirect them to the serial appending the special character ($) to each message.
4. Start the RemoteBlinkApp on the Android emulator and follow this steps:
   • click on the emulator button on the bottom of the screen, you won't need to pair with any bluetooth device since you're using the serial
   • The LedSwitchEmulatedActivity will open check the code here to extend it for your assignments
   • You should be able to turn the led on and off