How to log all WiFi and bluetooth devices in the area

I am in the security business and I found an app that can log all the Bluetooth and WiFi devices that have been in the area. This helps us track who has been in and out of the building and at what time (very big advantage). The app is called Radar Bluetooth WIFI detector and can be downloaded here: https://play.google.com/store/apps/details?id=com.colony.radarlite