ESP32 & Node-RED TCP OUT Node

ESP32 is TCP Client - Node-RED is TCP Server

1.3 TCP/IP ESP32

ESP32 supply a library that make ESP32 become a client or server. There are some classes that you need to know:

1.3.1 WiFi
We use this class to create a connection to WiFi. It is a static class and It has some important member functions:

- WiFi.begin(ssid, password): You should replace ssid and password with your WiFi ssid and password accordingly.
- WiFi.status(): return the current status of WiFi (connect or not)
- WiFi.localIP(): to get the current local IP address of ESP32.
1.3.2 WiFiClient
We use this class to create a TCP Client instance. It has some important member functions:
- connect(host, port): connect to a TCP server at host (IP address) and port
- print(data[]): send data to server
- stop(): stop connection
- available(): check whether data available for reading or not
- read(): read one byte of data
- read(uint8_t *buf, size_t size): read size bytes of data in to buf
- write(uint8_t data): write one byte data
- write(const uint8_t *buf, size_t size): write size bytes in buf
- connected(): is client connected

1.3.3 WiFiServer
We use this class to create a TCP Server instance. It has some important member functions:
- begin(): start Server
- available(): is there a client want to connect.
- accept(): accept the client connection
- write(uint8_t data): write one byte data
- write(const uint8_t *buf, size_t size): write size bytes in buf
For more information you can refer WiFiClient.h and WiFiServer.h

/*

 * This is the IP address of your PC

 * [Wins: use ipconfig command, Linux: use ifconfig command]

*/

const char* host = "192.168.43.121";

注意IP Address

#include <WiFi.h>

/* change ssid and password according to yours WiFi*/

//const char* ssid     = "<SSID>";

//const char* password = "<Passwort>";

const char* ssid     = "alex9ufo";

const char* password = "alex9981";

/*

 * This is the IP address of your PC

 * [Wins: use ipconfig command, Linux: use ifconfig command]

*/

const char* host = "192.168.43.121";

const int port = 8088;

void setup()

{

    Serial.begin(115200);

    Serial.print("Connecting to ");

    Serial.println(ssid);

    /* connect to your WiFi */

    WiFi.begin(ssid, password);

    /* wait until ESP32 connect to WiFi*/

    while (WiFi.status() != WL_CONNECTED) {

        delay(500);

        Serial.print(".");

    }

    Serial.println("");

    Serial.println("WiFi connected with IP address: ");

    Serial.println(WiFi.localIP());

}

void loop()

{

    delay(5000);

    Serial.print("connecting to ");

    Serial.println(host);

    /* Use WiFiClient class to create TCP connections */

    WiFiClient client;

    

    if (!client.connect(host, port)) {

        Serial.println("connection failed");

        return;

    }

    /* This will send the data to the server */

    client.print("Hello world From Arduino ESP32");

    client.stop();

}

Json檔案

[{"id":"cdf905ab.fb0718","type":"tcp in","z":"dfe6f708.aa2998","name":"","server":"server","host":"","port":"8088","datamode":"stream","datatype":"utf8","newline":"","topic":"","base64":false,"x":220,"y":60,"wires":[["c3dd673c.a35d18"]]},{"id":"c3dd673c.a35d18","type":"debug","z":"dfe6f708.aa2998","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":490,"y":60,"wires":[]},{"id":"e8ea98d6.d2fd98","type":"tcp out","z":"dfe6f708.aa2998","host":"192.168.43.121","port":"8088","beserver":"client","base64":false,"end":false,"name":"","x":550,"y":200,"wires":[]},{"id":"f7aeb8a7.499e88","type":"inject","z":"dfe6f708.aa2998","name":"","topic":"","payload":"Hello ESP32 & Node-RED","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":270,"y":200,"wires":[["e8ea98d6.d2fd98"]]}]