Development of an Anti-Kidnapping Mobile App with a Portable Emergency Button

The alarming rise in kidnapping incidents across Nigeria demands innovative, reliable, and context-appropriate personal safety solutions. Existing GSM panic buttons and mobile applications are often hindered by hardware constraints, dependence on constant internet connectivity, and slow activation under duress. This paper presents the design and implementation of an anti-kidnapping system that integrates an ESP8266-based emergency button with an Android mobile application, enabling dual-mode alert delivery via Internet or SMS. When the emergency button is pressed, the ESP8266 powers on and instantly enters Wi-Fi Access Point (AP) mode. The Android application, running a foreground service, connects as a client, acquires GPS coordinates from the phone, and combines them with a timestamp and the user’s preconfigured emergency contacts. This information is sent to an IoT server, which triggers notifications via Firebase Cloud Messaging. If internet connectivity is unavailable, the application automatically switches to SMS mode to ensure alert delivery. Hardware-triggered activation and firmware-controlled power-down ensure zero standby power consumption, enabling extended operational readiness on a single charge. Field tests across varying connectivity conditions showed activation in less than 2 seconds, alert delivery in 5–9 s depending on connectivity, and GPS accuracy typically within ±10 m. The system’s low cost, portability, and independence from continuous network access make it suitable for deployment across Nigeria’s urban, rural, and low-resource settings, with potential for broader emergency response applications.