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--- products:camel:camelv1 [2023/01/13 09:49] – manu
+++ products:camel:camelv1 [2023/01/13 18:21] (current) – manu
@@ Line 33: / Line 33: @@
 ===== - Manuel utilisateur =====
 {{ :products:camel:camelv1_user_manual_fr.pdf |}}
+===== - Javascript Codec to decode LoRaWAN frames =====
+The function used to parse the bytes transmitted in LoRaWAN
+<sxh javascript; first-line: 1;>
+// Decode decodes an array of bytes into an object.
+//  - fPort contains the LoRaWAN fPort number
+//  - bytes is an array of bytes, e.g. [225, 230, 255, 0]
+// The function must return an object, e.g. {"temperature": 22.5}
+var TEMP_BYTE_0_IDX = 0;
+var TEMP_BYTE_1_IDX = 1;
+var RH_BYTE_0_IDX = 2;
+var RH_BYTE_1_IDX = 3;
+var VOLT_BYTE_0_IDX = 4;
+var LORA_MIN_BATT_VAL = 1;
+var LORA_MAX_BATT_VAL = 254;
+var LORA_BATT_RANGE = LORA_MAX_BATT_VAL - LORA_MIN_BATT_VAL;
+var LORA_BATT_ERROR = 255;
+var BATT_VOLTAGE_LOW = 3.0;
+var BATT_VOLTAGE_HIGH = 4.2;
+function Decode(fPort, bytes) {
+    var temperature_code = 0;
+    var humidity_code = 0;
+    var temperature = 0.0;
+    var humidity = 0.0;
+    var voltage_code = 0;
+    var voltage = 0.0
+    temperature_code =  (bytes[TEMP_BYTE_0_IDX] << 8 ) + bytes[TEMP_BYTE_1_IDX];
+    humidity_code = (bytes[RH_BYTE_0_IDX] << 8 ) + bytes[RH_BYTE_1_IDX];
+    voltage_code = bytes[VOLT_BYTE_0_IDX];
+    temperature = ((175.72 * temperature_code) / 65536.0) - 46.85;
+    humidity = ((125.0 * humidity_code) / 65536.0) - 6.0;
+    var data = {};
+    if (voltage_code !=  LORA_BATT_ERROR) {
+        voltage = (((voltage_code - LORA_MIN_BATT_VAL) * (BATT_VOLTAGE_HIGH - BATT_VOLTAGE_LOW))/LORA_BATT_RANGE) + BATT_VOLTAGE_LOW;
+        data =
+        {
+            "temperature": temperature,
+            "humidity": humidity,
+            "voltage" : voltage,
+            "raw": bytes,
+        };
+    }
+    else {
+        data =
+        {
+            "temperature": temperature,
+            "humidity": humidity,
+            "raw": bytes,
+        };
+    }
+    return data;
+}
+</sxh>