Smart Anti-Theft Smartphone Ecosystem with Offline Remote Access Using BLE and GSM

Abstract: Tracking apps that run on a phone stop working once a thief switches the handset off or cuts its connection, so the owner loses both the device and any way of reaching it. This paper presents an anti-theft ecosystem in which recovery is handled by a separate companion tracker with a battery of its own, a dedicated SIM card and a built-in satellite receiver. The tracker combines an ESP32-class controller, a GPS receiver and a SIM800L GSM/GPRS modem. It sends its position to an online dashboard, replies to location requests received as text messages, issues an SOS alert carrying a map link when a button is held, and accepts calls from the owner. A temporary Wi-Fi page stores the device identity, API key, access point name, upload interval and emergency numbers in flash memory, so no secret is written into the program. A Bluetooth Low Energy layer that detects separation from the phone is specified as the planned extension. The prototype was exercised through its configuration portal and its text-message interface; the observed behaviour, including a location reply carrying six satellites and an SOS alert delivered with a map link, is reported. Weaknesses of the present firmware and the next development steps are also discussed.

Keywords: Bluetooth Low Energy, GSM, GPS, anti-theft, offline tracking, SOS alert, ESP32, SIM800L, smartphone recovery.