Arduino以太网插板让你轻松将你的Arduino连接因特网。这个插板可以让Arduino发送和接收来自世界任何角落的数据。你可以用它来做有意思的东西，比如用网站远程控制机器人，或者每次你收到一个新的twitter信息都会响一次铃。这个插板开启了无穷尽的可能性，让你立刻将你的项目介入因特网。

第一步：安装

安装很简单，将插板头部的引脚针插入你的Arduino。

第二步：插板特征

以太网插板基于W5100芯片（WIZnet），带有一个16K的内部缓冲区。连接速率高达10/100Mb。

依赖于Arduino以太网库，和开发环境捆绑。

还有一个板载微型SD卡槽，可以让你存储可查找到的数据。这需要使用外部SD库，它并不附带软件。本教程不涵盖SD卡。在无线SD卡的Step 8中可以找到。

这个板子也有空间增加PoE模块，它可以给Arduino连接以太网供电。

完整的技术概述，请看官方以太网插板页。

第三步：启动

将Arduino与你电脑USB口连接；以太网插板连接路由器（或直接联网）

接下来，打开Arduino开发环境。我强烈推荐更新Arduino 1.0及以上版本（如果你还没有用过）。这个软件版本支持DHCP，不需要手动配置一个IP地址

要清楚分配到你板子上的IP地址是多少，打开DhcpAddressPrinter：
File --> Examples --> Ethernet --> DhcpAddressPrinter

打开后，你可能需要换个MAC地址。在较新的以太网插板版本，你应该看到板子上贴了个地址标签。如果你弄丢了这个标签，就编个能工作的唯一地址。如果您使用多个插板，要保证MAC地址的唯一性。

MAC地址配置好后，上传代码到你的Arduino，打开串口监控器。它会打出使用中的IP地址。

第四步：服务器

你可以将Arduino插板用作一个网络服务器，来负载一个HTML页或者聊天服务器功能。你也可以解析请求客户端发送，就像一个网络浏览器。下面的两个例子说明了怎样使用它来负载HTML页，和解析URL字符串。

重要的是要记住，你需要输入你的Arduino IP地址在下面两个例子中，这样才能工作。

下面的代码将网页服务改换到基于一个按钮：

/* Web Server Demo thrown together by Randy Sarafan A simple web server that changes the page that is served, triggered by a button press. Circuit: * Ethernet shield attached to pins 10, 11, 12, 13 * Connect a button between Pin D2 and 5V * Connect a 10K resistor between Pin D2 and ground Based almost entirely upon Web Server by Tom Igoe and David Mellis Edit history: created 18 Dec 2009 by David A. Mellis modified 4 Sep 2010 by Tom Igoe */

#include #include

// Enter a MAC address and IP address for your controller below. // The IP address will be dependent on your local network: byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDA, 0x02 };

IPAddress ip(191,11,1,1);

//<<< ENTER YOUR IP ADDRESS HERE!!!

// Initialize the Ethernet server library // with the IP address and port you want to use // (port 80 is default for HTTP): EthernetServer server(80);

int buttonPress = 1;

void setup() { pinMode(2, INPUT);

// start the Ethernet connection and the server: Ethernet.begin(mac, ip); server.begin(); }

void loop() {

buttonPress = digitalRead(2);

// listen for incoming clients

EthernetClient client = server.available();

if (client) {

// an http request ends with a blank line

boolean currentLineIsBlank = true;

while (client.connected()) {

if (client.available()) {

char c = client.read();

// if you've gotten to the end of the line (received a newline character) and the line is blank, the http request has ended,

// so you can send a reply

if (c == '\n' && currentLineIsBlank) {

// send a standard http response header

client.println("HTTP/1.1 200 OK");

client.println("Content-Type: text/html");

client.println();

//serves a different version of a website depending on whether or not the button

//connected to pin 2 is pressed.

if (buttonPress == 1) {

client.println("LIGHT!");

}

else if (buttonPress == 0){

client.println("DARK! ");

}

break;

}

if (c == '\n') {

// you're starting a new line currentLineIsBlank = true;

}

else if (c != '\r') {

// you've gotten a character on the current line currentLineIsBlank = false;

}

}

}

// give the web browser time to receive the data

delay(1);

// close the connection:

client.stop();

}

}

让这个样例代码工作，附上一个一个按钮在 D2引脚和5V之间，一个10K电阻在 D2引脚与接地之间，然后负载你的ArduinoIP地址到你的网页浏览器。网页应该打开一个黑色的背景。按下这个按钮并保持住，然后刷新页面。这页面将会打开一个白色背景。

下面的代码在URL上点亮一个LED，并发送到Arduino：

/* Web Server Demo thrown together by Randy Sarafan Allows you to turn on and off an LED by entering different urls. To turn it on:http://your-IP-address/$1To turn it off:http://your-IP-address/$2Circuit: * Ethernet shield attached to pins 10, 11, 12, 13 * Connect an LED to pin D2 and put it in series with a 220 ohm resistor to ground Based almost entirely upon Web Server by Tom Igoe and David Mellis Edit history: created 18 Dec 2009 by David A. Mellis modified 4 Sep 2010 by Tom Igoe */

#include #include

boolean incoming = 0;

// Enter a MAC address and IP address for your controller below.

// The IP address will be dependent on your local network: byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDA, 0x02 };

IPAddress ip(191,11,1,1);

//<<< ENTER YOUR IP ADDRESS HERE!!!

// Initialize the Ethernet server library // with the IP address and port you want to use

// (port 80 is default for HTTP): EthernetServer server(80);

void setup() {

pinMode(2, OUTPUT);

// start the Ethernet connection and the server:

Ethernet.begin(mac, ip);

server.begin();

Serial.begin(9600); }

void loop() {

// listen for incoming clients

EthernetClient client = server.available();

if (client) {

// an http request ends with a blank line

boolean currentLineIsBlank = true;

while (client.connected()) {

if (client.available()) {

char c = client.read();

// if you've gotten to the end of the line (received a newline character) and the line is blank, the http request has ended,

// so you can send a reply

//reads URL string from $ to first blank space

if(incoming && c == ' '){

incoming = 0;

}

if(c == '$'){

incoming = 1;

}

//Checks for the URL string $1 or $2

if(incoming == 1){

Serial.println(c);

if(c == '1'){

Serial.println("ON");

digitalWrite(2, HIGH);

}

if(c == '2'){

Serial.println("OFF");

digitalWrite(2, LOW);

}

}

if (c == '\n') {

// you're starting a new line

currentLineIsBlank = true;

}

else if (c != '\r') {

// you've gotten a character on the current line

currentLineIsBlank = false;

}

}

}

// give the web browser time to receive the data

delay(1);

// close the connection:

client.stop();

}

}

将正极引导LED连接到引脚D2，负极连接220欧姆电阻到地。

打开LED键入这个到你的浏览器：

http://[YOUR IP ADDRESS HERE]/$1

关闭LED键入这个到你的浏览器：

http://[YOUR IP ADDRESS HERE]/$2

注意：很明显你应该用你的IP地址替换[YOUR IP ADDRESS HERE]

第五步：客户端

你也可以使用以太网插板作为一个客户端。换言说，你可以用它像个网页浏览器一个读取网页。

网页也有可见和隐藏的文本，这样使其在客户端编程变得非常棘手。读网页信息通常涉及到解析很多字符串。这很让人受不了，但是值得的是，如果这正是你想要的。

我写一些读Twitter信息的代码，但这代码已经作为Arduino编辑器的例子存在了。相反，我只需要稍微修改一下，就可以在信息被读的时候 点亮一个LED灯。

连接正极引导LED到引脚D2，连接负极引导220欧姆电阻接地。

不要忘记键入你的IP地址到下面的代码，不然它不会工作的。

代码如下：

/* Twitter Client with Strings This sketch connects to Twitter using an Ethernet shield. It parses the XML returned, and looks for this is a tweet You can use the Arduino Ethernet shield, or the Adafruit Ethernet shield, either one will work, as long as it's got a Wiznet Ethernet module on board. This example uses the DHCP routines in the Ethernet library which is part of the Arduino core from version 1.0 beta 1 This example uses the String library, which is part of the Arduino core from version 0019. Circuit: * Ethernet shield attached to pins 10, 11, 12, 13 created 21 May 2011 by Tom Igoe This code is in the public domain. */

#include #include

// Enter a MAC address and IP address for your controller below.

// The IP address will be dependent on your local network: byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x01 };

IPAddress ip(191,11,1,1);

//<<< ENTER YOUR IP ADDRESS HERE!!!

// initialize the library instance: EthernetClient client;

const int requestInterval = 60000;

// delay between requests

char serverName[] = "api.twitter.com";

// twitter URL

boolean requested;

// whether you've made a request since connecting long lastAttemptTime = 0;

// last time you connected to the server, in milliseconds

String currentLine = "";

// string to hold the text from server String tweet = "";

// string to hold the tweet boolean readingTweet = false;

// if you're currently reading the tweet

void setup() {

pinMode(2, OUTPUT);

// reserve space for the strings: currentLine.reserve(256); tweet.reserve(150);

// initialize serial: Serial.begin(9600);

// attempt a DHCP connection:

if (!Ethernet.begin(mac)) {

// if DHCP fails, start with a hard-coded address:

Ethernet.begin(mac, ip); }

// connect to Twitter: connectToServer(); }

void loop() {

if (client.connected()) {

if (client.available()) {

// read incoming bytes:

char inChar = client.read();

// add incoming byte to end of line:

currentLine += inChar;

// if you get a newline, clear the line:

if (inChar == '\n') {

currentLine = ""; }

// if the current line ends with , it will

// be followed by the tweet:

if ( currentLine.endsWith("")) {

// tweet is beginning. Clear the tweet string:

readingTweet = true;

tweet = ""; }

// if you're currently reading the bytes of a tweet,

// add them to the tweet String:

if (readingTweet) {

if (inChar != '<') {

tweet += inChar;

}

else {

// if you got a "<" character,

// you've reached the end of the tweet:

readingTweet = false;

Serial.println(tweet);

if(tweet == ">Hello Cruel World"){

digitalWrite(2, HIGH);

Serial.println("LED ON!"); }

if(tweet != ">Hello Cruel World"){

digitalWrite(2, LOW);

Serial.println("LED OFF!");

}

// close the connection to the server:

client.stop();

}

}

}

}

else if (millis() - lastAttemptTime > requestInterval) {

// if you're not connected, and two minutes have passed since

// your last connection, then attempt to connect again:

connectToServer(); } }

void connectToServer() {

// attempt to connect, and wait a millisecond:

Serial.println("connecting to server...");

if (client.connect(serverName, 80)) {

Serial.println("making HTTP request...");

// make HTTP GET request to twitter:

client.println("GET /1/statuses/user_timeline.xml?screen_name=RandyMcTester&count=1 HTTP/1.1"); client.println("HOST: api.twitter.com");

client.println(); }

// note the time of this connect attempt:

lastAttemptTime = millis();

}

也许你想读一些其他最近的帖子在 RandyMcTester Twitter feed
阅读其他Twitter feed, 改变下面的文本:
client.println("GET /1/statuses/user_timeline.xml?screen_name=[NEW TWITTER NAME HERE]&count=1 HTTP/1.1");

翻译自：http://www.instructables.com/id/Arduino-Ethernet-Shield-Tutorial/

感谢您的阅读！

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