![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/Big-Timer-Node-RED-ESP8266.jpg?resize=1200%2C675&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nProject Overview<\/h2>\n\n\n\n
The Big Timer Node was created by Peter Scargill. We recommend taking a look at the Big Timer page on Peter Scargill\u2019s blog: Big Timer page.<\/a> Consider donating to the author if you think this node will be useful for your projects.<\/p>\n\n\n\n To show you how you can use the Big Timer node in Node-RED to control the ESP8266 based on schedules, we’ll set up a system that automatically turns the ESP8266 GPIOs on and off at certain times. The Big Timer node allows you to set up complex schedule rules to determine when the GPIOs will be on and off.<\/p>\n\n\n\n To communicate between Node-RED and the ESP8266, we’ll use MQTT communication protocol. Learn more about MQTT: What is MQTT and How It Works<\/a>.<\/p>\n\n\n\n The following diagram shows a high-level overview of the example we’ll build.<\/p>\n\n\n This project is divided into two parts:<\/p>\n\n\n\n Before continuing, make sure you follow all the next pre-requisites:<\/p>\n\n\n\n In this section, we’ll program the ESP8266 to subscribe to the same topic that the Big Timer node is publishing. Then, we’ll automatically set the corresponding ESP8266 output states to on or off depending on the message received via MQTT.<\/p>\n\n\n\n There are several MQTT libraries that you can use to set the ESP8266 as an MQTT client. We\u2019ll use the AsyncMQTT library. Click on the following link to download the library ZIP file:<\/p>\n\n\n\n You also need to install the ESPAsyncTCP library. Click on the following link to download the library:<\/p>\n\n\n\n Now that you\u2019ve downloaded all the required library files, let\u2019s install them.<\/p>\n\n\n\n Open your Arduino IDE, go to Sketch<\/strong> > Include Library<\/strong> > Add .ZIP library, <\/strong>and select the ZIP file for the AsyncMQTT library. Repeat the same process for the AsyncTCP library. After installing the libraries, restart your Arduino IDE and proceed to the next unit.<\/p>\n\n\n After installing the required libraries, you can finally program the ESP8266 to subscribe to an MQTT topic and turn the GPIOs on and off automatically.<\/p>\n\n\n\n Upload the following code to your board\u2014before uploading you need to insert your network credentials (SSID and password), MQTT broker IP address or URL, MQTT username and password, if applicable.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n![\"Big](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/Big-Timer-Node-RED-MQTT-ESP8266-Overview-02.png?resize=1200%2C1033&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\n
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Prerequisites<\/h2>\n\n\n\n
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1) Program the ESP8266 – Subscribe to MQTT Topic (Receive Big Timer messages)<\/h2>\n\n\n\n
Installing the AsyncMQTT Library<\/h3>\n\n\n\n
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![\"Arduino](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/install-library-arduino-ide-via-zip.png?resize=573%2C262&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nProgramming the ESP8266 – Subscribe to MQTT Topic<\/h3>\n\n\n\n
\/*********\n Rui Santos\n Complete project details: https:\/\/randomnerdtutorials.com\/esp8266-nodemcu-big-timer-node-red\/\n \n Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.\n The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.\n*********\/\n\n#include <Arduino.h>\n\n#include <ESP8266WiFi.h>\n#include <Ticker.h>\n#include <AsyncMqttClient.h>\n\n#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"\n#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD"\n\n\/\/ BROKER\n#define MQTT_HOST IPAddress(192, 168, 1, XXX) \/\/MQTT BROKER IP ADDRESS\n\/*for example:\n#define MQTT_HOST IPAddress(192, 168, 1, 106)*\/\n#define MQTT_PORT 1883\n#define BROKER_USER "REPLACE_WITH_BROKER_USERNAME"\n#define BROKER_PASS "REPLACE_WITH_BROKER_PASSWORD"\n\n\/\/MQTT Subscribe Topics\n#define MQTT_SUB_DIGITAL "esp8266\/digital\/#"\n\nAsyncMqttClient mqttClient;\n\nTicker mqttReconnectTimer;\nWiFiEventHandler wifiConnectHandler;\nWiFiEventHandler wifiDisconnectHandler;\nTicker wifiReconnectTimer;\n\n\nvoid connectToWifi() {\n Serial.println("Connecting to Wi-Fi...");\n WiFi.begin(WIFI_SSID, WIFI_PASSWORD);\n}\n\nvoid connectToMqtt() {\n Serial.println("Connecting to MQTT...");\n mqttClient.connect();\n}\n\nvoid onWifiConnect(const WiFiEventStationModeGotIP& event) {\n Serial.println("Connected to Wi-Fi.");\n connectToMqtt();\n}\n\nvoid onWifiDisconnect(const WiFiEventStationModeDisconnected& event) {\n Serial.println("Disconnected from Wi-Fi.");\n mqttReconnectTimer.detach(); \/\/ ensure we don't reconnect to MQTT while reconnecting to Wi-Fi\n wifiReconnectTimer.once(2, connectToWifi);\n}\n\nvoid onMqttConnect(bool sessionPresent) {\n Serial.println("Connected to MQTT.");\n Serial.print("Session present: ");\n Serial.println(sessionPresent);\n \/\/Subscribe to topics\n \/\/ Subscribe to topic MQTT_SUB_DIGITAL when it connects to the broker\n uint16_t packetIdSub1 = mqttClient.subscribe(MQTT_SUB_DIGITAL, 2);\n Serial.print("Subscribing at QoS 2, packetId: ");\n Serial.println(packetIdSub1);\n}\n\nvoid onMqttDisconnect(AsyncMqttClientDisconnectReason reason) {\n Serial.println("Disconnected from MQTT.");\n\n if (WiFi.isConnected()) {\n mqttReconnectTimer.once(2, connectToMqtt);\n }\n}\n\nvoid onMqttSubscribe(uint16_t packetId, uint8_t qos) {\n Serial.println("Subscribe acknowledged.");\n Serial.print(" packetId: ");\n Serial.println(packetId);\n Serial.print(" qos: ");\n Serial.println(qos);\n}\n\nvoid onMqttMessage(char* topic, char* payload, AsyncMqttClientMessageProperties properties, size_t len, size_t index, size_t total) {\n \/\/ Do whatever you want when you receive a message\n \n \/\/ Save the message in a variable\n String receivedMessage;\n for (int i = 0; i < len; i++) {\n Serial.println((char)payload[i]);\n receivedMessage += (char)payload[i];\n }\n \/\/ Save topic in a String variable\n String receivedTopic = String(topic); \n Serial.print("Received Topic: ");\n Serial.println(receivedTopic);\n\n \/\/ Check which GPIO we want to control\n int stringLen = receivedTopic.length();\n \/\/ Get the index of the last slash\n int lastSlash = receivedTopic.lastIndexOf("\/");\n \/\/ Get the GPIO number (it's after the last slash "\/")\n \/\/ esp\/digital\/GPIO\n String gpio = receivedTopic.substring(lastSlash+1, stringLen);\n Serial.print("DIGITAL GPIO: ");\n Serial.println(gpio);\n Serial.print("STATE: ");\n Serial.println(receivedMessage);\n\n \/\/ Check if it is DIGITAL\n if (receivedTopic.indexOf("digital") > 0) {\n \/\/Set the specified GPIO as output\n pinMode(gpio.toInt(), OUTPUT);\n \/\/Control the GPIO\n if (receivedMessage == "1"){\n digitalWrite(gpio.toInt(), HIGH);\n }\n else{\n digitalWrite(gpio.toInt(), LOW);\n }\n }\n Serial.println("Publish received.");\n Serial.print(" topic: ");\n Serial.println(topic);\n Serial.print(" qos: ");\n Serial.println(properties.qos);\n Serial.print(" dup: ");\n Serial.println(properties.dup);\n Serial.print(" retain: ");\n Serial.println(properties.retain);\n Serial.print(" len: ");\n Serial.println(len);\n Serial.print(" index: ");\n Serial.println(index);\n Serial.print(" total: ");\n Serial.println(total);\n}\n\nvoid onMqttPublish(uint16_t packetId) {\n Serial.println("Publish acknowledged.");\n Serial.print(" packetId: ");\n Serial.println(packetId);\n}\n\nvoid setup() {\n Serial.begin(115200);\n Serial.println();\n Serial.println();\n\n wifiConnectHandler = WiFi.onStationModeGotIP(onWifiConnect);\n wifiDisconnectHandler = WiFi.onStationModeDisconnected(onWifiDisconnect);\n\n mqttClient.onConnect(onMqttConnect);\n mqttClient.onDisconnect(onMqttDisconnect);\n mqttClient.onSubscribe(onMqttSubscribe);\n mqttClient.onMessage(onMqttMessage);\n mqttClient.onPublish(onMqttPublish);\n \n mqttClient.setServer(MQTT_HOST, MQTT_PORT);\n mqttClient.setCredentials(BROKER_USER, BROKER_PASS);\n\n connectToWifi();\n}\n\nvoid loop() {\n\n}\n<\/code><\/pre>\n\tHow the Code Works<\/h3>\n\n\n\n
![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/esp8266-subscribe-to-topic-mqtt-serial-monitor.png?resize=601%2C349&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Set](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/big-timer-with-mqtt-example-flow-node-red.png?resize=439%2C130&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"edit](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/set-up-mqtt-broker-node.png?resize=657%2C517&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Node-RED](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/MQTT-node-publish-message-ESP8266.png?resize=527%2C392&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Setting](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/big-timer-set-on-time-off-time-messages.png?resize=606%2C891&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"set](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/big-timer-node-red-repeat-output.png?resize=429%2C180&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"set](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2023\/03\/debug-node-complete-msg-object.png?resize=518%2C356&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"Node-RED](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2022\/06\/Node-RED-deploy-button.png?resize=136%2C35&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n