单片机开关灯是必须的，如何告知ros2，这里用主题方式实现。需要先阅读：
开关灯的示例如下：
#include <WiFi.h>
const char* ssid = "yourssid";
const char* password = "yourpasswd";
WiFiServer server(80);
void setup()
{
Serial.begin(115200);
pinMode(5, OUTPUT); // set the LED pin mode
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected.");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
server.begin();
}
int value = 0;
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 the LED on pin 5 on.<br>");
client.print("Click <a href=\"/L\">here</a> to turn the LED on pin 5 off.<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(5, HIGH); // GET /H turns the LED on
}
if (currentLine.endsWith("GET /L")) {
digitalWrite(5, LOW); // GET /L turns the LED off
}
}
}
// close the connection:
client.stop();
Serial.println("Client Disconnected.");
}
}这是示例代码，一定要注意！LED端口要与电路板一致，本开发板要修改为2。
pinMode(2, OUTPUT); // set the LED pin mode还有：
if (currentLine.endsWith("GET /H")) {
digitalWrite(2, HIGH); // GET /H turns the LED on
}
if (currentLine.endsWith("GET /L")) {
digitalWrite(2, LOW); // GET /L turns the LED off
}这和ROS2有啥关系？完全没有啊，下面直接插入ROS2相关代码，源码如下：
#include <ros2arduino.h>
#include <WiFi.h>
#include <WiFiUdp.h>
#include <WiFiClient.h>
//#include <WebServer.h>
//#include <ESPmDNS.h>
#define SSID "ESP32LoveROS2"
#define SSID_PW "66666666"
#define AGENT_IP "172.20.10.2"
#define AGENT_PORT 2021 //AGENT port number
#define LED 2
#define PUBLISH_FREQUENCY 1 //hz
char ledflag=2;
void publishString(std_msgs::String* msg, void* arg)
{
(void)(arg);
static int cnt = 0;
if(ledflag==2){
sprintf(msg->data, "欢乐的esp32和ros2 %d", cnt++);
}
else if(ledflag==0)
{
sprintf(msg->data, "欢乐的esp32灯灭了 %d", cnt++);
}
else if(ledflag==1)
{
sprintf(msg->data, "欢乐的esp32灯亮了 %d", cnt++);
}
}
class StringPub : public ros2::Node
{
public:
StringPub()
: Node("esp32_pub_node")
{
ros2::Publisher<std_msgs::String>* publisher_ = this->createPublisher<std_msgs::String>("esp32_chatter");
this->createWallFreq(PUBLISH_FREQUENCY, (ros2::CallbackFunc)publishString, nullptr, publisher_);
}
};
WiFiUDP udp;
WiFiServer server(80);
void setup()
{
pinMode(LED, OUTPUT);
WiFi.begin(SSID, SSID_PW);
while(WiFi.status() != WL_CONNECTED);
server.begin();
ros2::init(&udp, AGENT_IP, AGENT_PORT);
}
void loop()
{
static StringPub StringNode;
ros2::spin(&StringNode);
WiFiClient client = server.available(); // listen for incoming clients
if (client) { // if you get a client,
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
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 the LED on pin 2 on. cslg<br>");
client.print("Click <a href=\"/L\">here</a> to turn the LED on pin 2 off. cslg<br>");
client.print("Click <a href=\"/Blink\">here</a> to turn the LED on pin 2 off. cslg<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, HIGH); // GET /H turns the LED on
// sprintf(msg->data, "灯亮了");
ledflag=1;
}
if (currentLine.endsWith("GET /L")) {
digitalWrite(LED, LOW); // GET /L turns the LED off
// sprintf(msg->data, "灯灭了");
ledflag=0;
}
}
}
// close the connection:
client.stop();
}
}如果不能理解这段代码，先阅读本文最初的那个链接。
效果是如下的：
后续，小乌龟和机器人都会加入进来^_^