CovertTrack Bluetooth Tracker

The Bluetooth Tracker app allows you to discover all Bluetooth Low Energy devices that are advertising in the nearby area and monitor their signal strength using visual and audio features to estimate proximity to your location.
When a device is discovered, the app will display its broadcasted name and UID and allow you to start a monitoring session. While monitoring, the app will display your device's signal strength in real-time using a bar graph. Additionally, you can setup detection alerts (vibration or a short sound) that will notify you when a device is discovered during your live monitoring session without having to keep an eye on the phone. Alerts can be configured as a one-time alert (triggered when a device is initially detected during your session) or scaling (alert gets faster as the RSSI signal gets stronger). This app also gives you an option to assign a friendly name to your discovered device or you can assign it ahead of time if you know your device’s ID (applies to CTG devices only).
This app is useful for anyone who wants to detect a specific Bluetooth Low Energy device in the area and actively monitor its signal strength to estimate how close or far the device is. For example, if you misplaced your BLE device in your house and can't remember where it is, this app will help you locate it.
Note that Bluetooth Tracker app will only detect those BLE devices that are actively advertising.