[209] | 1 | /*
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| 2 | Basic MQTT example
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| 3 |
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| 4 | This sketch demonstrates the basic capabilities of the library.
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| 5 | It connects to an MQTT server then:
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| 6 | - publishes "hello world" to the topic "outTopic"
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| 7 | - subscribes to the topic "inTopic", printing out any messages
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| 8 | it receives. NB - it assumes the received payloads are strings not binary
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| 9 |
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| 10 | It will reconnect to the server if the connection is lost using a blocking
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| 11 | reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
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| 12 | achieve the same result without blocking the main loop.
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| 13 |
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| 14 | */
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| 15 |
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| 16 | #include <SPI.h>
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| 17 | #include <Ethernet.h>
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| 18 | #include <PubSubClient.h>
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| 19 |
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| 20 | // Update these with values suitable for your network.
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| 21 | byte mac[] = { 0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
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| 22 | IPAddress ip(172, 16, 0, 100);
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| 23 | IPAddress server(172, 16, 0, 2);
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| 24 |
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| 25 | void callback(char* topic, byte* payload, unsigned int length) {
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| 26 | Serial.print("Message arrived [");
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| 27 | Serial.print(topic);
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| 28 | Serial.print("] ");
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| 29 | for (int i=0;i<length;i++) {
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| 30 | Serial.print((char)payload[i]);
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| 31 | }
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| 32 | Serial.println();
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| 33 | }
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| 34 |
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| 35 | EthernetClient ethClient;
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| 36 | PubSubClient client(ethClient);
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| 37 |
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| 38 | void reconnect() {
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| 39 | // Loop until we're reconnected
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| 40 | while (!client.connected()) {
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| 41 | Serial.print("Attempting MQTT connection...");
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| 42 | // Attempt to connect
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| 43 | if (client.connect("arduinoClient")) {
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| 44 | Serial.println("connected");
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| 45 | // Once connected, publish an announcement...
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| 46 | client.publish("outTopic","hello world");
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| 47 | // ... and resubscribe
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| 48 | client.subscribe("inTopic");
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| 49 | } else {
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| 50 | Serial.print("failed, rc=");
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| 51 | Serial.print(client.state());
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| 52 | Serial.println(" try again in 5 seconds");
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| 53 | // Wait 5 seconds before retrying
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| 54 | delay(5000);
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| 55 | }
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| 56 | }
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| 57 | }
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| 58 |
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| 59 | void setup()
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| 60 | {
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| 61 | Serial.begin(57600);
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| 62 |
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| 63 | client.setServer(server, 1883);
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| 64 | client.setCallback(callback);
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| 65 |
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| 66 | Ethernet.begin(mac, ip);
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| 67 | // Allow the hardware to sort itself out
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| 68 | delay(1500);
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| 69 | }
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| 70 |
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| 71 | void loop()
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| 72 | {
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| 73 | if (!client.connected()) {
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| 74 | reconnect();
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| 75 | }
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| 76 | client.loop();
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| 77 | }
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