From c006d3a106efad9e1ef9dd617ec34dadc378848f Mon Sep 17 00:00:00 2001
From: Tony Stork <tm24fan8@gmail.com>
Date: Sat, 24 May 2025 20:16:41 -0400
Subject: [PATCH] Sensor to convert station pressure to SLP

---
 flows.json | 146 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)

diff --git a/flows.json b/flows.json
index 3a7a912..8468d75 100644
--- a/flows.json
+++ b/flows.json
@@ -2876,6 +2876,24 @@
         "w": 1072,
         "h": 202
     },
+    {
+        "id": "f5eea6eac47f79a8",
+        "type": "group",
+        "z": "ebd5561c4f077718",
+        "name": "Station Pressure to SLP",
+        "style": {
+            "label": true
+        },
+        "nodes": [
+            "e8dbc16027e1addb",
+            "350e11750f05c353",
+            "7da31d8bd0d544bd"
+        ],
+        "x": 794,
+        "y": 859,
+        "w": 712,
+        "h": 82
+    },
     {
         "id": "fba69dfc80829db7",
         "type": "junction",
@@ -5849,6 +5867,47 @@
         "resend": false,
         "debugEnabled": false
     },
+    {
+        "id": "8f61788e0c4471e1",
+        "type": "ha-entity-config",
+        "server": "9e87348d.9c1c48",
+        "deviceConfig": "",
+        "name": "Home Tempest Local SLP",
+        "version": 6,
+        "entityType": "sensor",
+        "haConfig": [
+            {
+                "property": "name",
+                "value": "Home Tempest Local SLP"
+            },
+            {
+                "property": "icon",
+                "value": "mdi:gauge"
+            },
+            {
+                "property": "entity_picture",
+                "value": ""
+            },
+            {
+                "property": "entity_category",
+                "value": ""
+            },
+            {
+                "property": "device_class",
+                "value": "atmospheric_pressure"
+            },
+            {
+                "property": "unit_of_measurement",
+                "value": "inHg"
+            },
+            {
+                "property": "state_class",
+                "value": "measurement"
+            }
+        ],
+        "resend": false,
+        "debugEnabled": false
+    },
     {
         "id": "afead614fabc01bb",
         "type": "function",
@@ -33690,6 +33749,93 @@
         "y": 1340,
         "wires": []
     },
+    {
+        "id": "e8dbc16027e1addb",
+        "type": "function",
+        "z": "ebd5561c4f077718",
+        "g": "f5eea6eac47f79a8",
+        "name": "Pressure Conversion",
+        "func": "const states = global.get('homeassistant.homeAssistant.states')\nconst temp_F = states['sensor.home_tempest_temperature'].state\nconst elevation_ft = 693\n\n// Get the pressure from the payload\nlet pressure_inHg = msg.payload\n\nif (isNaN(pressure_inHg)) {\n    node.error(\"Invalid pressure value in msg.payload: \" + msg.payload)\n    msg.payload = null\n    return null\n}\n\n// Convert pressure from inHg to hPa\nlet pressure_hPa = pressure_inHg * 33.8639\n\n// Convert temperature to °C\nlet temp_C = (temp_F - 32) * (5 / 9)\n\n// Convert elevation from feet to meters\nlet elevation_m = elevation_ft / 3.28084\n\n// Apply the barometric formula\nlet slp = pressure_hPa * Math.pow(\n    1 - ((0.0065 * elevation_m) / (temp_C + (0.0065 * elevation_m) + 273.15)),\n    -5.257\n)\n\n// Optional: Convert back to inHg\nlet slp_inHg = slp / 33.8639\n\n// Round both values\nslp = Math.round(slp * 100) / 100\nslp_inHg = Math.round(slp_inHg * 100) / 100\n\n// Return the SLP value\nmsg.payload = slp_inHg\n\nnode.status({fill:'Success',shape:'dot',text:'green'})\n\nreturn msg\n",
+        "outputs": 1,
+        "timeout": 0,
+        "noerr": 0,
+        "initialize": "",
+        "finalize": "",
+        "libs": [],
+        "x": 1120,
+        "y": 900,
+        "wires": [
+            [
+                "7da31d8bd0d544bd"
+            ]
+        ]
+    },
+    {
+        "id": "350e11750f05c353",
+        "type": "server-state-changed",
+        "z": "ebd5561c4f077718",
+        "g": "f5eea6eac47f79a8",
+        "name": "Station Pressure",
+        "server": "9e87348d.9c1c48",
+        "version": 6,
+        "outputs": 1,
+        "exposeAsEntityConfig": "",
+        "entities": {
+            "entity": [
+                "sensor.home_tempest_air_pressure"
+            ],
+            "substring": [],
+            "regex": []
+        },
+        "outputInitially": false,
+        "stateType": "num",
+        "ifState": "",
+        "ifStateType": "str",
+        "ifStateOperator": "is",
+        "outputOnlyOnStateChange": true,
+        "for": "0",
+        "forType": "num",
+        "forUnits": "minutes",
+        "ignorePrevStateNull": false,
+        "ignorePrevStateUnknown": false,
+        "ignorePrevStateUnavailable": false,
+        "ignoreCurrentStateUnknown": true,
+        "ignoreCurrentStateUnavailable": true,
+        "outputProperties": [
+            {
+                "property": "payload",
+                "propertyType": "msg",
+                "value": "",
+                "valueType": "entityState"
+            }
+        ],
+        "x": 900,
+        "y": 900,
+        "wires": [
+            [
+                "e8dbc16027e1addb"
+            ]
+        ]
+    },
+    {
+        "id": "7da31d8bd0d544bd",
+        "type": "ha-sensor",
+        "z": "ebd5561c4f077718",
+        "g": "f5eea6eac47f79a8",
+        "name": "Home Tempest Local SLP",
+        "entityConfig": "8f61788e0c4471e1",
+        "version": 0,
+        "state": "payload",
+        "stateType": "msg",
+        "attributes": [],
+        "inputOverride": "allow",
+        "outputProperties": [],
+        "x": 1370,
+        "y": 900,
+        "wires": [
+            []
+        ]
+    },
     {
         "id": "1f7af146c06b8b85",
         "type": "ha-select",