Make Your Own Smart Wireless Biometric Lock

This smart wireless biometric lock system operates by bridging mobile app logic with a physical microcontroller-based circuit. At the heart of the system is an Arduino Uno, which continuously monitors for incoming wireless data. The user interacts with a custom Android application built via Kodular on a smartphone, which features a fingerprint scanner integration. When a user places their finger on the smartphone's built-in biometric sensor, the phone authenticates the print and wirelessly transmits a specific command string over a short-range wireless connection using an HC-05 Bluetooth module. The Arduino board receives this serial data via its RX/TX lines and processes the incoming instruction. Upon recognizing the valid authentication command, the Arduino outputs a specific Pulse Width Modulation (PWM) signal to a connected servo motor. The servo motor acts as the physical actuator, rotating its output horn by a predetermined angle to move a connected mechanical lock into an unlocked position. Power is supplied to the entire circuit through an external power supply, which ensures that both the logic board and the higher-current servo motor receive adequate electrical energy to function without causing voltage drops on the microcontroller's logic rails. Jumper wires are used to route power, ground, and signal lines between the Arduino Uno, the HC-05 module, and the servo motor, completing the closed-loop access control system.