{ "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=&bucket=&precision=s", "body": "={{ $json.payload }}", "method": "POST", "options": {}, "sendBody": true, "contentType": "raw", "sendHeaders": true, "headerParameters": { "parameters": [ { "name": "Authorization", "value": "Token " } ] } }, "notesInFlow": true, "typeVersion": 4.2 }, { "id": "6abe1212-b128-492f-b485-401a4315fcbc", "name": "Payload data preparation node", "type": "n8n-nodes-base.code", "position": [ -180, -220 ], "parameters": { "jsCode": "// Try to parse the incoming message as JSON\nlet data;\ntry {\n data = JSON.parse($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 } ] ] } } }