Workflow: Remote IOT Sensor monitoring via MQTT and InfluxDB
Integrations: code, httpRequest, mqttTrigger, stickyNote

{"id": "6pOGYw5O3iOY1Gc6", "meta": {"instanceId": "7221598654c32899e94731aab144bdcd338735c2ac218dc0873131caa0be0ef8", "templateCredsSetupCompleted": true}, "name": "Remote IOT Sensor monitoring via MQTT and InfluxDB", "tags": [], "nodes": [{"id": "4997f226-f236-4d27-bea4-904744d9ff07", "name": "Sticky Note", "type": "n8n-nodes-base.stickyNote", "position": [-700, -360], "parameters": {"width": 340, "height": 120, "content": "MQTT trigger subscribed to a topic called wokwi-weather via a Mosquitto MQTT broker. The trigger receives the temperature and humidity payloads from a DHT22 sensor connected to a remote ESP32 microcontroller "}, "typeVersion": 1}, {"id": "9d4f1da6-fda3-4312-a6b1-bd0ac499dde7", "name": "Sticky Note1", "type": "n8n-nodes-base.stickyNote", "position": [-240, -360], "parameters": {"height": 100, "content": "Javascript code to extract the temperature and humidity values to ensure correct JSON format for the database"}, "typeVersion": 1}, {"id": "d8f01dba-5019-457e-8c1a-99c802282fdf", "name": "Sticky Note3", "type": "n8n-nodes-base.stickyNote", "position": [140, -360], "parameters": {"width": 260, "height": 120, "content": "HTTP request node posts temperature and humidity data from the DHT22 sensor to the InfluxDB data bucket running on a local host http://localhost:8086"}, "typeVersion": 1}, {"id": "020858a6-7771-4322-8eb6-b83e99b3563d", "name": "Remote Sensor MQTT Trigger", "type": "n8n-nodes-base.mqttTrigger", "position": [-580, -220], "parameters": {"topics": "wokwi-weather", "options": {}}, "credentials": {"mqtt": {"id": "xtd75tjk1hKlQOba", "name": "MQTT account"}}, "typeVersion": 1}, {"id": "51e6f59f-9b93-4121-8db4-7f47b929fdf5", "name": "Data ingest to InfluxDB bucket", "type": "n8n-nodes-base.httpRequest", "position": [200, -220], "parameters": {"url": "http://localhost:8086/api/v2/write?orgID=<Organization ID>&bucket=<InfluxDB bucket name>&precision=s", "body": "={{ $json.payload }}", "method": "POST", "options": {}, "sendBody": true, "contentType": "raw", "sendHeaders": true, "headerParameters": {"parameters": [{"name": "Authorization", "value": "Token  <API Token value generated in InfluxDB>"}]}}, "notesInFlow": true, "typeVersion": 4.2}, {"id": "6abe1212-b128-492f-b485-401a4315fcbc", "name": "Payload data preparation node", "type": "n8n-nodes-base.code", "position": [-180, -220], "parameters": {"jsCode": "// Try to parse the incoming message as JSON\nlet data;\ntry {\n  data = JSON.parse($json.message); // $json.message is expected to be a JSON string\n} catch (e) {\n  // If parsing fails, throw an error\n  throw new Error(\"Invalid JSON in MQTT message\");\n}\n\n// Get the topic from the input, or use a default value\nconst topic = $json.topic || \"unknown-topic\";\n\n// Make sure humidity and temp are numbers\nif (typeof data.humidity !== \"number\" || typeof data.temp !== \"number\") {\n  throw new Error(\"Missing or invalid humidity/temp in MQTT message\");\n}\n\n// Create a formatted string like: \"topic_name humidity=45,temp=22\"\nconst line = `${topic} humidity=${data.humidity},temp=${data.temp}`;\n\n// Return the result in the expected format\nreturn [\n  {\n    json: {\n      payload: line\n    }\n  }\n];"}, "typeVersion": 2}], "active": false, "pinData": {}, "settings": {"executionOrder": "v1"}, "versionId": "d1311dca-5edf-4f14-86b9-629937cd3416", "connections": {"Remote Sensor MQTT Trigger": {"main": [[{"node": "Payload data preparation node", "type": "main", "index": 0}]]}, "Payload data preparation node": {"main": [[{"node": "Data ingest to InfluxDB bucket", "type": "main", "index": 0}]]}}}