The Beacon technology based on Bluetooth Low Energy (BLE), allows Bluetooth devices to transmit and receive small messages within short distances. Simply put, it consists of two parts: a presenter and a receiver. The presenter always advertises himself saying "I am here, my name is ...", while the receiver detects these beacon sensors and does all that is necessary, depending on how close or far it is from them. Normally, the observer is an App, while the presenter / transmitter can be one of the popular beacon devices.