support for specifying different pairings

libs/bluetooth/pxt.json

@@ -38,7 +38,33 @@
                 }
             },
             "gatt_table_size": "0x700"
-        }
+        },
+        "userConfigs": [
+            {
+                "description": "No pairing: Anyone can connect via Bluetooth.",
+                "config": {
+                    "microbit-dal": {
+                        "bluetooth": {
+                            "open": 1,
+                            "pairing_mode": null,
+                            "security_level": null
+                        }
+                    }
+                }
+            },
+            {
+                "description": "Passkey pairing: Button press and 6 digit key to pair via Bluetooth.",
+                "config": {
+                    "microbit-dal": {
+                        "bluetooth": {
+                            "open": 0,
+                            "pairing_mode": 1,
+                            "security_level": "SECURITY_MODE_ENCRYPTION_WITH_MITM"
+                        }
+                    }
+                }
+            }
+        ]
     },
     "installedVersion": "vzlhfd"
 }