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這篇文章主要講解了“ESP8266+MQTT怎么實(shí)現(xiàn)LED燈的遠(yuǎn)程控制”,文中的講解內(nèi)容簡(jiǎn)單清晰,易于學(xué)習(xí)與理解,下面請(qǐng)大家跟著小編的思路慢慢深入,一起來(lái)研究和學(xué)習(xí)“ESP8266+MQTT怎么實(shí)現(xiàn)LED燈的遠(yuǎn)程控制”吧!
MQTT 是輕量級(jí)的、靈活的物聯(lián)網(wǎng)消息交換和數(shù)據(jù)傳遞協(xié)議,致力于為 IoT 開發(fā)人員實(shí)現(xiàn)靈活性與硬件/網(wǎng)絡(luò)資源的平衡。
NodeMCU 是一個(gè)開源的物聯(lián)網(wǎng)平臺(tái)。它使用 Lua 語(yǔ)言編程。該平臺(tái)基于eLua開源項(xiàng)目,底層使用ESP8266 sdk 0.9.5版本。
在此項(xiàng)目中我們將實(shí)現(xiàn) NodeMCU(ESP8266) 與 EMQ X Cloud 運(yùn)營(yíng)和維護(hù)的免費(fèi)公共 MQTT 服務(wù)器遠(yuǎn)程控制 LED 燈,并使用 Arduino IDE 來(lái)對(duì) NodeMCU ESP8266 進(jìn)行編程。 EMQ X Cloud 是由 EMQ 推出的安全的 MQTT 物聯(lián)網(wǎng)云服務(wù)平臺(tái),它提供一站式運(yùn)維代管、獨(dú)有隔離環(huán)境的 MQTT 5.0 接入服務(wù)。
NodeMCU
Arduino IDE
LED * 1,330 Ω 電阻
MQTT X: 優(yōu)雅的跨平臺(tái) MQTT 5.0 客戶端工具
免費(fèi)的公共 MQTT 服務(wù)器
Broker: broker.emqx.io
TCP Port: 1883
Websocket Port: 8083
首先我們將導(dǎo)入 ESP8266WiFi 和 PubSubClient 庫(kù),ESP8266WiFi 庫(kù)能夠?qū)?ESP8266 連接到 WiFi 網(wǎng)絡(luò),PubSubClient 庫(kù),使我們能夠連接到 MQTT 代理并發(fā)布/訂閱主題消息。
#include <ESP8266WiFi.h> #include <PubSubClient.h>
我們將使用 NodeMCU ESP8266 的 D1 引腳來(lái)連接到 LED,實(shí)際上該引腳內(nèi)部連接到 ESP8266 模塊的 GPIO5。
// GPIO 5 D1 #define LED 5
設(shè)置 WIFI 名稱和密碼,以及 MQTT Broker 連接地址和端口
// WiFi const char *ssid = "mousse"; // Enter your WiFi name const char *password = "qweqweqwe"; // Enter WiFi password // MQTT Broker const char *mqtt_broker = "broker.emqx.io"; const char *topic = "esp8266/led"; const char *mqtt_username = "emqx"; const char *mqtt_password = "public"; const int mqtt_port = 1883;
我們打開了一個(gè)串行連接,以便于輸出程序的結(jié)果并且連接到WiFi網(wǎng)絡(luò)
// Set software serial baud to 115200; Serial.begin(115200); // connecting to a WiFi network WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.println("Connecting to WiFi.."); }
我們將設(shè)置 MQTT Broker,同時(shí)將連接信息打印到串口監(jiān)視器上
//connecting to a mqtt broker client.setServer(mqtt_broker, mqtt_port); client.setCallback(callback); while (!client.connected()) { String client_id = "esp8266-client-"; client_id += String(WiFi.macAddress()); Serial.println("Connecting to public emqx mqtt broker....."); if (client.connect(client_id, mqtt_username, mqtt_password)) { Serial.println("Public emqx mqtt broker connected"); } else { Serial.print("failed with state "); Serial.print(client.state()); delay(2000); } }
MQTT Broker 連接成功后,ESP8266 將向 MQTT Broker 發(fā)布和訂閱消息
// publish and subscribe client.publish(topic, "hello emqx"); client.subscribe(topic);
編寫回調(diào)函數(shù),從串行監(jiān)視器讀取下發(fā)指令并且控制 LED 的開和關(guān)
void callback(char *topic, byte *payload, unsigned int length) { Serial.print("Message arrived in topic: "); Serial.println(topic); Serial.print("Message:"); String message; for (int i = 0; i < length; i++) { message = message + (char) payload[i]; // convert *byte to string } Serial.print(message); if (message == "on") { digitalWrite(LED, LOW); } // LED on if (message == "off") { digitalWrite(LED, HIGH); } // LED off Serial.println(); Serial.println("-----------------------"); }
完整代碼
#include <ESP8266WiFi.h> #include <PubSubClient.h> // GPIO 5 D1 #define LED 5 // WiFi const char *ssid = "mousse"; // Enter your WiFi name const char *password = "qweqweqwe"; // Enter WiFi password // MQTT Broker const char *mqtt_broker = "broker.emqx.io"; const char *topic = "esp8266/led"; const char *mqtt_username = "emqx"; const char *mqtt_password = "public"; const int mqtt_port = 1883; WiFiClient espClient; PubSubClient client(espClient); void setup() { // Set software serial baud to 115200; Serial.begin(115200); // connecting to a WiFi network WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.println("Connecting to WiFi.."); } Serial.println("Connected to the WiFi network"); //connecting to a mqtt broker client.setServer(mqtt_broker, mqtt_port); client.setCallback(callback); while (!client.connected()) { String client_id = "esp8266-client-"; client_id += String(WiFi.macAddress()); Serial.println("Connecting to public emqx mqtt broker....."); if (client.connect(client_id, mqtt_username, mqtt_password)) { Serial.println("Public emqx mqtt broker connected"); } else { Serial.print("failed with state "); Serial.print(client.state()); delay(2000); } } // publish and subscribe client.publish(topic, "hello emqx"); client.subscribe(topic); } void callback(char *topic, byte *payload, unsigned int length) { Serial.print("Message arrived in topic: "); Serial.println(topic); Serial.print("Message:"); String message; for (int i = 0; i < length; i++) { message = message + (char) payload[i]; // convert *byte to string } Serial.print(message); if (message == "on") { digitalWrite(LED, LOW); } // LED on if (message == "off") { digitalWrite(LED, HIGH); } // LED off Serial.println(); Serial.println("-----------------------"); } void loop() { client.loop(); }
請(qǐng)使用 Arduino IDE 將完整代碼上傳 ESP8266,并打開串口監(jiān)視器
建立 MQTTX 客戶端 與 MQTT Broker 連接, 并向 ESP8266 發(fā)送指令
感謝各位的閱讀,以上就是“ESP8266+MQTT怎么實(shí)現(xiàn)LED燈的遠(yuǎn)程控制”的內(nèi)容了,經(jīng)過(guò)本文的學(xué)習(xí)后,相信大家對(duì)ESP8266+MQTT怎么實(shí)現(xiàn)LED燈的遠(yuǎn)程控制這一問(wèn)題有了更深刻的體會(huì),具體使用情況還需要大家實(shí)踐驗(yàn)證。這里是億速云,小編將為大家推送更多相關(guān)知識(shí)點(diǎn)的文章,歡迎關(guān)注!
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