Wio Terminal 无线 WiFi 配置
本文主要介绍 Wio Terminal 的 WiFi 功能，并演示如何使用 SeeedStudio 的 Arduino 库来配置 WiFi 工作模式和建立无线连接。
Wio Terminal 配备的无线网卡是 Realtek RTL8720，在开始本次学习之前，请确保你已经阅读 Wio Terminal 网卡固件更新，并完成固件更新和 Arduino 依赖库的安装。
我们知道，WiFi 有两种工作模式：AP 模式和 STA 模式。
- AP（Access Point）也就是无线接入点，是一个无线网络的创建者，是网络的中心节点。一般家庭或办公室使用的无线路由器就一个 AP。
- STA（Station）也就是站点，每一个连接到无线网络中的终端（如笔记本电脑、PDA 及其它可以联网的用户设备）都可称为一个站点。
本文会分别介绍 STA 和 AP 模式的使用情况。
配置为 STA 模式
Wio Terminal 的 Wi-Fi 配置依赖 rpcWiFi 库，所以需要在 Arduino 中 添加 rpcWifi.h 头文件，然后就可以通过下面代码将无线网卡配置为 STA 模式。
WiFi.mode(WIFI_STA);
扫描 Wi-Fi 网络
下面示例将 Wio Terminal 配置为 Wi-Fi STA 模式，然后扫描所有可用的 WiFi 接入网络，并将其打印到串口监视器。
#include "rpcWiFi.h"
void setup() {
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
delay(1000);
// Set WiFi to station mode and disconnect from an AP if it was previously connected
WiFi.mode(WIFI_STA);
WiFi.disconnect();
delay(100);
Serial.println("Setup done");
}
void loop() {
Serial.println("scan start");
// WiFi.scanNetworks will return the number of networks found
int n = WiFi.scanNetworks();
Serial.println("scan done");
if (n == 0) {
Serial.println("no networks found");
} else {
Serial.print(n);
Serial.println(" networks found");
for (int i = 0; i < n; ++i) {
// Print SSID and RSSI for each network found
Serial.print(i + 1);
Serial.print(": ");
Serial.print(WiFi.SSID(i));
Serial.print(" (");
Serial.print(WiFi.RSSI(i));
Serial.print(")");
Serial.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN) ? " " : "*");
delay(10);
}
}
Serial.println("");
// Wait a bit before scanning again
delay(5000);
}
连接 Wi-Fi 网络
下面示例将 Wio Terminal 连接到指定的 WiFi 网络。（需要将 ssid 和 password 修改为你的 WiFi 网络）
#include "rpcWiFi.h"
const char* ssid = "yourNetworkName";
const char* password = "yourNetworkPassword";
void setup() {
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
// Set WiFi to station mode and disconnect from an AP if it was previously connected
WiFi.mode(WIFI_STA);
WiFi.disconnect();
Serial.println("Connecting to WiFi..");
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.println("Connecting to WiFi..");
WiFi.begin(ssid, password);
}
Serial.println("Connected to the WiFi network");
Serial.print("IP Address: ");
Serial.println (WiFi.localIP()); // prints out the device's IP address
}
void loop() {
}
Wi-Fi 多连接示例
有时候我们需要配置多个 WiFi 连接信息，以便设备自动扫描并连接最佳的 WiFi 网络。在 Wio Terminal 中，我们可以使用 WiFiMulti 类来达到这个目的。
wifiMulti.addAP("ssid", "password");
只需要将多个 AP（WiFi 接入点）添加到列表中，wifiMulti.run() 将尝试连接到信号最好的 WiFi。
注意：记得根据你的网络情况修改 SSID 和 Password 参数。
#include "rpcWiFi.h"
#include <WiFiMulti.h>
WiFiMulti wifiMulti;
void setup() {
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
delay(1000);
wifiMulti.addAP("ssid_from_AP_1", "your_password_for_AP_1");
wifiMulti.addAP("ssid_from_AP_2", "your_password_for_AP_2");
wifiMulti.addAP("ssid_from_AP_3", "your_password_for_AP_3");
Serial.println("Connecting Wifi...");
if (wifiMulti.run() == WL_CONNECTED) {
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
}
void loop() {
if (wifiMulti.run() != WL_CONNECTED) {
Serial.println("WiFi not connected!");
delay(1000);
}
}
配置为 AP 模式（Web Server）
下面介绍如何将 Wio Terminal 配置为 AP 模式，并启动一个简单的 Web Server。
首先，配置为 AP 模式需要依赖 rpcWiFi.h、WiFiClient.h 和 WifiAP.h 三个头文件。然后使用 WiFiServer 创建服务器对象，参数 80 表示端口号。
WiFiServer server(80);
使用 ssid 和 password 参数初始化 AP：
WiFi.softAP(ssid, password);
启动 Web Server：
server.begin();
下面是完整的示例代码，在本示例中，首先将 Wio Terminal 配置为一个简单的 Web 服务器，并允许你（比如手机）连接到其 AP 网络并根据 HTTP 上的响应控制硬件。
/*
WiFiAccessPoint.ino creates a WiFi access point and provides a web server on it.
Steps:
1. Connect to the access point "yourAp"
2. Point your web browser to http://<This-AP-IP>/H to turn the LED on or http://<This-AP-IP>/L to turn it off
(<This-AP-IP> should be replaced with the IP got in terminal/SerialPort, see Note 1)
OR
Run raw TCP "GET /H" and "GET /L" on PuTTY terminal with IP address (see Note 1) and 80 as port
Created for arduino-esp32 on 04 July, 2018
by Elochukwu Ifediora (fedy0)
*/
#include <rpcWiFi.h>
#include <WiFiClient.h>
#include <WiFiAP.h>
#define LED_BUILTIN 2 // Set the GPIO pin where you connected your test LED
// or comment this line out if your dev board has a built-in LED
// Set these to your desired credentials.
const char* ssid = "yourAP";
const char* password = "yourPassword";
WiFiServer server(80);
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
delay(1000);
Serial.println();
Serial.println("Configuring access point...");
// You can remove the password parameter if you want the AP to be open.
WiFi.softAP(ssid, password);
IPAddress myIP = WiFi.softAPIP();
/*
* Note 1
* Record this IP, will used by Client (such as Web Browser)
*/
Serial.print("AP IP address: ");
Serial.println(myIP);
server.begin();
Serial.println("Server started");
}
void loop() {
WiFiClient client = server.available(); // listen for incoming clients
if (client) { // if you get a client,
Serial.println("New Client."); // print a message out the serial port
String currentLine = ""; // make a String to hold incoming data from the client
while (client.connected()) { // loop while the client's connected
if (client.available()) { // if there's bytes to read from the client,
char c = client.read(); // read a byte, then
Serial.write(c); // print it out the serial monitor
if (c == '\n') { // if the byte is a newline character
// if the current line is blank, you got two newline characters in a row.
// that's the end of the client HTTP request, so send a response:
if (currentLine.length() == 0) {
// HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
// and a content-type so the client knows what's coming, then a blank line:
client.println("HTTP/1.1 200 OK");
client.println("Content-type:text/html");
client.println();
// the content of the HTTP response follows the header:
client.print("Click <a href=\"/H\">here</a> to turn ON the LED.<br/>");
client.print("Click <a href=\"/L\">here</a> to turn OFF the LED.<br/>");
// The HTTP response ends with another blank line:
client.println();
// break out of the while loop:
break;
} else { // if you got a newline, then clear currentLine:
currentLine = "";
}
} else if (c != '\r') { // if you got anything else but a carriage return character,
currentLine += c; // add it to the end of the currentLine
}
// Check to see if the client request was "GET /H" or "GET /L":
if (currentLine.endsWith("GET /H")) {
digitalWrite(LED_BUILTIN, HIGH); // GET /H turns the LED on
}
if (currentLine.endsWith("GET /L")) {
digitalWrite(LED_BUILTIN, LOW); // GET /L turns the LED off
}
}
}
// close the connection:
client.stop();
Serial.println("Client Disconnected.");
}
}
将代码编译上传到 Wio Terminal，打开手机 WiFi 设置界面，可以看到一个名为 “Wio-Terminal” 的 WiFi 接入点，输入密码即可连接。
