ESP32 MQTT - Send data
To be able to receive data from an ESP32, I have prepared an MQTT broker as a Docker container. The container can be integrated into Home-Assistant and thus forward the data from the ESP32 to Home-Assistant via MQTT. On the part of ESP32, I tested sending with the following sketch and later integrated the relevant parts into another sketch.
MQTT - ESP32 - WiFi
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#include
#include
const char* ssid = "home";
const char* password = "???";
const char* mqttServer = "192.168.1.5";
const int mqttPort = 1883;
const char* mqttUser = "mqtt";
const char* mqttPassword = "???";
WiFiClient espClient;
PubSubClient client(espClient);
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.println("Connecting to WiFi..");
}
Serial.println("Connected to the WiFi network");
client.setServer(mqttServer, mqttPort);
while (!client.connected()) {
Serial.println("Connecting to MQTT...");
if (client.connect("ESP32Client", mqttUser, mqttPassword )) {
Serial.println("connected");
} else {
Serial.print("failed with state ");
Serial.print(client.state());
delay(2000);
}
}
client.publish("esp32/test", "Hello from ESP32");
}
void loop() {
client.loop();
}
Source: www.esp32learning.com/code/publishing-messages-to-mqtt-topic-using-an-esp32.php
When using the Eclipse-Mosquitto MQTT Docker image, the connection setup can be examined in the logs, see: MQTT Viewing Connections: Logs

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