Bluetooth-Controlled Mobile Robot for Long-Distance Selfie Capture Using a Master-Slave Dual-Smartphone Architecture and Arduino

Conventional selfie sticks, typically limited to a maximum reach of 1.5 m, are unable to effectively capture large group photographs or wide-background scenes, frequently resulting in restricted framing and facial cropping. This work presents the design, implementation, and experimental validation of a Bluetooth-controlled mobile robot with five degrees of freedom capable of capturing photographs at distances of up to 10 m using a dual-smartphone master–slave architecture. The proposed system integrates an Arduino Nano microcontroller, an L298N motor driver, three SG90 servo motors, an HC-05 Bluetooth module, and a rechargeable Li-Ion battery mounted on a four-wheel chassis. A master smartphone remotely controls both the mobile platform and the articulated camera arm, while a slave smartphone mounted on the arm captures images through its high-resolution rear camera with real-time video streaming. Experimental evaluations demonstrated 100% command transmission success at distances up to 10 m, automatic emergency stopping within 100–110 ms after Bluetooth disconnection, accurate face centering with minimal servo adjustments, and approximately 45 min of battery autonomy. The proposed open-source, low-cost teleoperated platform extends the effective photographic range from 1.5 m to 10 m while providing potentially improved photographic quality due to rear-camera imaging characteristics and full remote framing control compared with conventional selfie accessories.