Arduino-Unity-Bridge

Easy to use Serial Port communication Unity <-> Arduino.

Necessary settings on Unity

We need to open a serial port from within the mono environment. The mono environment Unity uses normally is a stripped down one. But this can be changed via Edit -> Project Settings -> Player. Look for a Setting called "Api Compatibility Level" and set it to ".NET 2.0".

Simple Example

On the Arduino

We put data on the Serial bus like this.

// Some variables we want to send to Unity
int someInt = 128;
float someFloat = 512.256f;
char* someString = "astring";

void setup() {
    // Open Serial Port
    Serial.begin(9600);
}

void loop() {
    delay(20);
    serialPrintf("someInt:%d,someFloat:%f,someString:%s", someInt, someFloat, someString);
}

Note that serialPrintf() is just a helper function converting different types to string. See "Arduino-Unity-Bridge.ino" for the full code (in the "Arduino Code" directory).

On Unity

Open the Arduino-Unity-Bridge project and hit play. You should see the transmitted values in the debug log. There is a GameObject with a script called "Arduino" on it. It contains the following code.

using UnityEngine;

public class Arduino : MonoBehaviour
{
    ArduinoSerial arduinoSerial;

    void Start()
    {
        arduinoSerial = new ArduinoSerial();
        arduinoSerial.ConnectToArduino(baudRate: 9600);
    }

    void Update()
    {
        Debug.Log("someInt: " + arduinoSerial.ReadInput("someInt"));
        Debug.Log("someFloat: " + arduinoSerial.ReadInput("someFloat"));
        Debug.Log("someString: " + arduinoSerial.ReadInput("someString"));
    }

    void OnApplicationQuit()
    {
        arduinoSerial.ClosePort();            
    }
}

Values from the Arduino are read by creating an instance of the ArduinoSerial class, setting it up with the same baud rate as specified on the arduino, and then calling arduinoSerial.ReadInput("someInt") on it. The argument "someInt" has to match with the text set on the Arduino like here : serialPrintf("someInt:%d,someFloat:%f,someString:%s", someInt, someFloat, someString);. Note how the key value pairs are separated by "," and the keys and values themselves are separated by ":" with no spaces in between.