一、Unity端发送消息，Arduino端接收消息 通过串口通信

Arduino端

#include <Arduino.h>#define PIN_KEY 5
uint item;void setup() {item = 0;Serial.begin(115200);pinMode(PIN_KEY, OUTPUT);  
}void loop() {if(Serial.available()>0){item = Serial.read();        }if(item == 'a'){digitalWrite(PIN_KEY,HIGH); }if(item == 'b'){digitalWrite(PIN_KEY,LOW); }
}

Unity端

public class Test : MonoBehaviour
{SerialPort port = new SerialPort("COM4", 115200);public Button Btn_Open;public Button Btn_Close;private void Start(){port.Open();port.ReadTimeout = 1;Btn_Open.onClick.AddListener(() => {port.WriteLine("a");});Btn_Close.onClick.AddListener(() => {port.WriteLine("b");});}
}

实现串口通信，点击开灯按钮，灯亮。关灯按钮，灯灭。

二、Unity端接收消息，Arduino端发送消息 通过串口通信

Arduino端

#include <Arduino.h>void setup() {Serial.begin(9600);
}void loop() {Serial.println("a");delay(1000);Serial.println("o");delay(1000);
}

Unity端

1.导入Ardity插件（在Unity商城中找）

2.打开读写实例场景

 3.添加读写的实例脚本

 4.

/*** Ardity (Serial Communication for Arduino + Unity)* Author: Daniel Wilches <dwilches@gmail.com>** This work is released under the Creative Commons Attributions license.* https://creativecommons.org/licenses/by/2.0/*/using UnityEngine;
using System.Collections;/*** Sample for reading using polling by yourself, and writing too.*/
public class SampleUserPolling_ReadWrite : MonoBehaviour
{public MeshRenderer Cube;public SerialController serialController;// Initializationvoid Start(){serialController = GameObject.Find("SerialController").GetComponent<SerialController>();Debug.Log("Press A or Z to execute some actions");}// Executed each framevoid Update(){//---------------------------------------------------------------------// Send data//---------------------------------------------------------------------// If you press one of these keys send it to the serial device. A// sample serial device that accepts this input is given in the README.if (Input.GetKeyDown(KeyCode.N)){Debug.Log("Sending n");serialController.SendSerialMessage("n");}if (Input.GetKeyDown(KeyCode.M)){Debug.Log("Sending m");serialController.SendSerialMessage("m");}//---------------------------------------------------------------------// Receive data//---------------------------------------------------------------------string message = serialController.ReadSerialMessage();if (message == null)return;// Check if the message is plain data or a connect/disconnect event.if (ReferenceEquals(message, SerialController.SERIAL_DEVICE_CONNECTED))Debug.Log("Connection established");else if (ReferenceEquals(message, SerialController.SERIAL_DEVICE_DISCONNECTED))Debug.Log("Connection attempt failed or disconnection detected");else {if (message.Equals("a")) {Cube.material.color = Color.red;}if (message.Equals("o")){Cube.material.color = Color.white;}Debug.Log("Message arrived: " + message);}}
}