Added eddystone UID module

Author: Renaud Vincent

modules/ble_eddystone_uid.js

@@ -0,0 +1,37 @@
+/** 
+ * Copyright (c) 2019 Renaud Vincent See the file LICENSE for copying permission.
+ * usage: require("ble_eddystone_uid").advertise([0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00], [0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);
+ */
+exports.get = function(namespace, instance) {
+  // UID encodings https://github.com/google/eddystone/tree/master/eddystone-uid
+  // Setup the frame format
+  var d = [
+    0x03, // Service UUID length
+    0x03, // Service UUID data type value
+    0xaa, // 16-bit Eddystone UUID
+    0xfe, // 16-bit Eddystone UUID
+    0x24, // Service Data length
+    0x16, // Service Data data type value
+    0xaa, // 16-bit Eddystone UUID
+    0xfe, // 16-bit Eddystone UUID
+    0x00, // Eddystone-uid frame type
+    0xf8, // txpower, use max but lower with NRF api
+  ];
+
+  d = d.concat(namespace);
+  d = d.concat(instance);
+  
+  // Necessary to adjust lenght
+  d[4] = d.length - 5;
+  
+  return d;
+};
+
+exports.advertise = function(namespace, instance, interval) {
+  NRF.setAdvertising(
+    exports.get(namespace, instance), 
+    {
+      interval: interval
+    }
+  );
+};