feat: Added min and max sensor config parameters.

Author: QuickSander

README.md

@@ -46,7 +46,9 @@ The configuration can contain the following properties:
 It currently expects the http server to return a float ranging from 0-100 (step 0.1) leaving out any html markup.
 * `pullInterval` \<integer\> **optional**: The property expects an interval in **milliseconds** in which the plugin
 pulls updates from your http device. For more information read [pulling updates](#the-pull-way).  
-* `debug` \<boolean\> **optional**: Enable debug mode and write more logs.  
+* `debug` \<boolean\> **optional**: Enable debug mode and write more logs.
+* `minValue` \<float>\> **optional**: Minimum lux value the sensor can return. Defaults to BH1750 light sensor module value: 2^16 -1 = 65535.
+* `maxValue` \<float>\> **optional**: Maximum lux value the sensor can return. Default to 0.0.
 
 Below are two example configurations. One is using a simple string url and the other is using a simple urlObject.  
 Both configs can be used for a basic plugin configuration.
@@ -78,6 +80,24 @@ Both configs can be used for a basic plugin configuration.
 }
 ```
 
+Specifying a custom min and max value for an 8 bit sensor:
+
+```json
+{
+    "accessories": [
+        {
+          "accessory": "HttpAmbientLightSensor",
+          "name": "Outdoor Light Sensor",
+
+          "getUrl": "http://localhost/api/lux",
+
+          "minValue": 1.0,
+          "maxValue": 255
+        }   
+    ]
+}
+```
+
 #### UrlObject
 
 A urlObject can have the following properties:

index.js

@@ -23,7 +23,7 @@ const MODEL = PACKAGE_JSON.name;
 const FIRMWARE_REVISION = PACKAGE_JSON.version;
 
 const MIN_LUX_VALUE = 0.0;
-const MAX_LUX_VALUE =  Math.pow(2, 16) - 1.0;
+const MAX_LUX_VALUE =  Math.pow(2, 16) - 1.0; // Default BH1750 max 16bit lux value.
 
 // -----------------------------------------------------------------------------
 // Exports
@@ -46,6 +46,8 @@ function HttpAmbientLightSensor(log, config) {
     this.log = log;
     this.name = config.name;
     this.debug = config.debug || false;
+    this.minSensorValue = config.minValue || MIN_LUX_VALUE;
+    this.maxSensorValue = config.maxValue || MAX_LUX_VALUE;
 
     if (config.getUrl) {
         try {
@@ -65,8 +67,8 @@ function HttpAmbientLightSensor(log, config) {
     this.homebridgeService = new Service.LightSensor(this.name);
     this.homebridgeService.getCharacteristic(Characteristic.CurrentAmbientLightLevel)
         .setProps({
-                    minValue: MIN_LUX_VALUE,
-                    maxValue: MAX_LUX_VALUE
+                    minValue: this.minSensorValue,
+                    maxValue: this.maxSensorValue
                 })
         .on("get", this.getSensorValue.bind(this));