[209] | 1 | /*
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| 2 | Basic ESP8266 MQTT example
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| 3 |
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| 4 | This sketch demonstrates the capabilities of the pubsub library in combination
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| 5 | with the ESP8266 board/library.
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| 6 |
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| 7 | It connects to an MQTT server then:
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| 8 | - publishes "hello world" to the topic "outTopic" every two seconds
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| 9 | - subscribes to the topic "inTopic", printing out any messages
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| 10 | it receives. NB - it assumes the received payloads are strings not binary
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| 11 | - If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
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| 12 | else switch it off
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| 13 |
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| 14 | It will reconnect to the server if the connection is lost using a blocking
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| 15 | reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
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| 16 | achieve the same result without blocking the main loop.
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| 17 |
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| 18 | To install the ESP8266 board, (using Arduino 1.6.4+):
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| 19 | - Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
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| 20 | http://arduino.esp8266.com/stable/package_esp8266com_index.json
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| 21 | - Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
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| 22 | - Select your ESP8266 in "Tools -> Board"
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| 23 |
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| 24 | */
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| 25 |
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| 26 | #include <ESP8266WiFi.h>
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| 27 | #include <PubSubClient.h>
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| 28 |
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| 29 | // Update these with values suitable for your network.
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| 30 |
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| 31 | const char* ssid = "........";
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| 32 | const char* password = "........";
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| 33 | const char* mqtt_server = "broker.mqtt-dashboard.com";
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| 34 |
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| 35 | WiFiClient espClient;
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| 36 | PubSubClient client(espClient);
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| 37 | long lastMsg = 0;
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| 38 | char msg[50];
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| 39 | int value = 0;
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| 40 |
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| 41 | void setup() {
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| 42 | pinMode(BUILTIN_LED, OUTPUT); // Initialize the BUILTIN_LED pin as an output
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| 43 | Serial.begin(115200);
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| 44 | setup_wifi();
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| 45 | client.setServer(mqtt_server, 1883);
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| 46 | client.setCallback(callback);
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| 47 | }
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| 48 |
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| 49 | void setup_wifi() {
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| 50 |
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| 51 | delay(10);
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| 52 | // We start by connecting to a WiFi network
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| 53 | Serial.println();
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| 54 | Serial.print("Connecting to ");
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| 55 | Serial.println(ssid);
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| 56 |
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| 57 | WiFi.begin(ssid, password);
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| 58 |
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| 59 | while (WiFi.status() != WL_CONNECTED) {
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| 60 | delay(500);
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| 61 | Serial.print(".");
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| 62 | }
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| 63 |
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| 64 | Serial.println("");
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| 65 | Serial.println("WiFi connected");
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| 66 | Serial.println("IP address: ");
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| 67 | Serial.println(WiFi.localIP());
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| 68 | }
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| 69 |
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| 70 | void callback(char* topic, byte* payload, unsigned int length) {
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| 71 | Serial.print("Message arrived [");
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| 72 | Serial.print(topic);
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| 73 | Serial.print("] ");
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| 74 | for (int i = 0; i < length; i++) {
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| 75 | Serial.print((char)payload[i]);
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| 76 | }
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| 77 | Serial.println();
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| 78 |
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| 79 | // Switch on the LED if an 1 was received as first character
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| 80 | if ((char)payload[0] == '1') {
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| 81 | digitalWrite(BUILTIN_LED, LOW); // Turn the LED on (Note that LOW is the voltage level
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| 82 | // but actually the LED is on; this is because
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| 83 | // it is acive low on the ESP-01)
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| 84 | } else {
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| 85 | digitalWrite(BUILTIN_LED, HIGH); // Turn the LED off by making the voltage HIGH
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| 86 | }
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| 87 |
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| 88 | }
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| 89 |
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| 90 | void reconnect() {
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| 91 | // Loop until we're reconnected
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| 92 | while (!client.connected()) {
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| 93 | Serial.print("Attempting MQTT connection...");
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| 94 | // Attempt to connect
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| 95 | if (client.connect("ESP8266Client")) {
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| 96 | Serial.println("connected");
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| 97 | // Once connected, publish an announcement...
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| 98 | client.publish("outTopic", "hello world");
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| 99 | // ... and resubscribe
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| 100 | client.subscribe("inTopic");
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| 101 | } else {
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| 102 | Serial.print("failed, rc=");
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| 103 | Serial.print(client.state());
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| 104 | Serial.println(" try again in 5 seconds");
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| 105 | // Wait 5 seconds before retrying
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| 106 | delay(5000);
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| 107 | }
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| 108 | }
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| 109 | }
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| 110 | void loop() {
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| 111 |
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| 112 | if (!client.connected()) {
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| 113 | reconnect();
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| 114 | }
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| 115 | client.loop();
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| 116 |
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| 117 | long now = millis();
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| 118 | if (now - lastMsg > 2000) {
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| 119 | lastMsg = now;
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| 120 | ++value;
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| 121 | snprintf (msg, 75, "hello world #%ld", value);
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| 122 | Serial.print("Publish message: ");
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| 123 | Serial.println(msg);
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| 124 | client.publish("outTopic", msg);
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| 125 | }
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| 126 | }
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