Design of a Contactless Doorbell using Ultrasonic Sensors and Embedded Automation

Abstract

With increasing concerns over hygiene and the spread of infectious diseases, contactless technologies have gained significant attention in smart home applications. This paper presents the design and implementation of a contactless doorbell system utilizing ultrasonic sensors and embedded automation to eliminate the need for physical contact. The proposed system employs ultrasonic proximity sensors to detect the presence of a visitor near the door, triggering the doorbell without any manual pressing. The embedded microcontroller processes the sensor data and actuates the buzzer or wireless notification system accordingly. The design focuses on optimizing sensor accuracy, response time, and power consumption to ensure reliability and user convenience. The system’s architecture integrates a microcontroller unit (MCU), ultrasonic sensors, buzzer module, and optionally, wireless communication modules for remote notifications. The ultrasonic sensor emits high-frequency sound waves, and the reflected echoes are analyzed to calculate the distance of approaching objects. When a visitor is detected within a preset range, the embedded controller triggers the doorbell. Extensive testing under various environmental conditions demonstrated that the system effectively distinguishes human presence from other objects, minimizing false alarms. The contactless doorbell also offers advantages such as ease of installation, low maintenance, and improved sanitation, making it suitable for residential and commercial applications. Additionally, the embedded automation allows for future expansions, including integration with IoT platforms and voice assistants. This paper details the design methodology, hardware selection, system workflow, and experimental results. Challenges such as sensor calibration, ambient noise interference, and power management are discussed alongside mitigation strategies. The findings support the adoption of contactless doorbell systems as practical solutions for enhancing convenience and health safety in modern smart homes.