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raymond |
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/*
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Basic ESP8266 MQTT example
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This sketch demonstrates the capabilities of the pubsub library in combination
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with the ESP8266 board/library.
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It connects to an MQTT server then:
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- publishes "hello world" to the topic "outTopic" every two seconds
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- subscribes to the topic "inTopic", printing out any messages
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it receives. NB - it assumes the received payloads are strings not binary
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- If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
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else switch it off
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It will reconnect to the server if the connection is lost using a blocking
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reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
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achieve the same result without blocking the main loop.
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To install the ESP8266 board, (using Arduino 1.6.4+):
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- Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
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http://arduino.esp8266.com/stable/package_esp8266com_index.json
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- Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
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- Select your ESP8266 in "Tools -> Board"
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*/
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#include <ESP8266WiFi.h>
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#include <PubSubClient.h>
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// Update these with values suitable for your network.
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const char* ssid = "........";
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const char* password = "........";
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const char* mqtt_server = "broker.mqtt-dashboard.com";
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WiFiClient espClient;
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PubSubClient client(espClient);
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unsigned long lastMsg = 0;
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#define MSG_BUFFER_SIZE (50)
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char msg[MSG_BUFFER_SIZE];
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int value = 0;
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void setup_wifi() {
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delay(10);
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// We start by connecting to a WiFi network
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Serial.println();
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Serial.print("Connecting to ");
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Serial.println(ssid);
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WiFi.mode(WIFI_STA);
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WiFi.begin(ssid, password);
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while (WiFi.status() != WL_CONNECTED) {
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delay(500);
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Serial.print(".");
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}
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randomSeed(micros());
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Serial.println("");
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Serial.println("WiFi connected");
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Serial.println("IP address: ");
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Serial.println(WiFi.localIP());
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}
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void callback(char* topic, byte* payload, unsigned int length) {
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Serial.print("Message arrived [");
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Serial.print(topic);
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Serial.print("] ");
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for (int i = 0; i < length; i++) {
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Serial.print((char)payload[i]);
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}
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Serial.println();
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// Switch on the LED if an 1 was received as first character
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if ((char)payload[0] == '1') {
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digitalWrite(BUILTIN_LED, LOW); // Turn the LED on (Note that LOW is the voltage level
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// but actually the LED is on; this is because
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// it is active low on the ESP-01)
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} else {
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digitalWrite(BUILTIN_LED, HIGH); // Turn the LED off by making the voltage HIGH
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}
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}
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void reconnect() {
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// Loop until we're reconnected
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while (!client.connected()) {
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Serial.print("Attempting MQTT connection...");
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// Create a random client ID
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String clientId = "ESP8266Client-";
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clientId += String(random(0xffff), HEX);
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// Attempt to connect
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if (client.connect(clientId.c_str())) {
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Serial.println("connected");
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// Once connected, publish an announcement...
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client.publish("outTopic", "hello world");
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// ... and resubscribe
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client.subscribe("inTopic");
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} else {
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Serial.print("failed, rc=");
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Serial.print(client.state());
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Serial.println(" try again in 5 seconds");
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// Wait 5 seconds before retrying
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delay(5000);
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}
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}
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}
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void setup() {
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pinMode(BUILTIN_LED, OUTPUT); // Initialize the BUILTIN_LED pin as an output
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Serial.begin(115200);
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setup_wifi();
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client.setServer(mqtt_server, 1883);
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client.setCallback(callback);
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}
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void loop() {
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if (!client.connected()) {
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reconnect();
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}
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client.loop();
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unsigned long now = millis();
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if (now - lastMsg > 2000) {
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lastMsg = now;
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++value;
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snprintf (msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
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Serial.print("Publish message: ");
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Serial.println(msg);
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client.publish("outTopic", msg);
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}
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}
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