Arduino for ODROID-GO - Bluetooth Serial

Make sure that you've followed these guides.
- Getting started with Arduino
- Arduino for ODROID-GO - Hello World

Refer to the Arduino official documents. This tells us useful common functions with great instructions.
- https://www.arduino.cc/reference/en/
Refer to the ESP32 official programming guide. Most of ESP32 specific functions introduced here.
- https://esp-idf.readthedocs.io/en/v3.0/
We don't need the odroid_go.h library for this step.

We will learn about how to communicate between ODROID-GO and your smartphone.

ESP32 which is used on ODROID-GO supports Bluetooth 4.2. So we can program Bluetooth features with helpful libraries on Arduino.
In this guide, we're going to use BluetoothSerial.h library.

This is the code. Quite simple.

#include "BluetoothSerial.h"
 
BluetoothSerial serialBT;
 
void setup() {
    Serial.begin(115200);
 
    serialBT.begin("ODROID-GO");
    Serial.println("The device started, now you can pair it with bluetooth!");
}
 
void loop() {
    if (Serial.available()) {
        serialBT.write(Serial.read());
    }
    if (serialBT.available()) {
        Serial.write(serialBT.read());
    }
    delay(20);
}

Define an instance for BluetoothSerial as a global variable, serialBT.
To set, we use begin() function having a parameter indicates the name of the Bluetooth device for the Bluetooth scanners. We named that ODROID-GO.

And in loop() function, if a message from the Serial monitor available, send that message to the connected device via Bluetooth serial.
On the other hand, if a message from the Bluetooth serial available, send that message to the host.

You can use a Serial monitor to watch the debug messages from the Serial port.
It is placed at the Tools → Serial Monitor menu to open. Or, you can press CTRL-SHIFT-M to open easily.

To show the message properly, you should select bandwidth to 115200 baud.