A Contactless Switch for Controlling Four Load Switching

Abstract

Intheeraofautomationandsmarttechnology,touch-free operationofelectricaldeviceshasgainedsignificantattentionduetoits advantagesinhygiene,convenience,andsafety.Thispaperpresentsthe design and implementation of acontactless switch capableof controlling four independent electrical loads. The system utilizes an infrared (IR) sensor-basedapproachtodetecthandgesturesorproximitymovements, therebyeliminating the need for physical contact.The proposed system comprises an IR transmitter-receiver module, a micro controller unit, and a relay circuit that facilitates switching operations. When a user places their hand near the sensor, the microcontroller interprets the signalandtriggersthecorrespondingrelaytoswitchthedesignatedload ON or OFF. The system is designed to handle multiple loads independently, making it suitable for applications in homes, hospitals, and public places where minimal physical interaction with switches is desired.The primary objectives of this study include enhancing user convenience, reducing wear and tear associated with mechanical switches, and improving safety by preventing electric shock hazards. The paper discusses the working principle, hardware design, software implementation, and performance analysis of the proposed system. Experimental results demonstrate the system’s reliability and responsiveness under different operating conditions.

Introduction

I. Introduction

The project presents a contactless switch system that uses infrared (IR) sensors and a microcontroller to control four independent electrical loads (two lights and two fans). It eliminates the need for physical touch, promoting hygiene, convenience, and safety, especially in sensitive environments like hospitals, public spaces, and smart homes.

II. Literature Review

Past studies show growing interest in touchless and IR-based switching:

• IR remotes for home automation (Kalayar Win, Ankit Jandial).

• Gesture-based smart home controls (Druvitha, Yegang Du).

• IoT-based remote switches.

• Industrial contactless switch systems controlling multiple loads using gesture sensors (Thomas Okello).

These works highlight the benefits of contactless systems but vary in implementation complexity, sensor types, and wireless integration.

III. System Overview

The proposed system consists of:

1. Power Supply – Converts 230V AC to 5V DC.

2. Sensors – IR gesture sensor and optional sound sensor detect hand movements or claps.

3. Microcontroller – STM32F103C8T6 ("Blue Pill") processes inputs and manages logic.

4. Relay Module – 4-channel opto-isolated relays switch AC loads safely.

5. Loads – Two lights and two fans controlled independently.

IV. Methodology

• The system continuously monitors user input via sensors.

• Processing logic: Gestures (e.g., swipes) and sounds (e.g., claps) trigger specific load actions.

• Firmware includes:

  • GPIO configuration,

  • Gesture/sound interpretation,

  • Debouncing and filtering,

  • State machine for load control.

• Prototyping was first done on a breadboard, then moved to a more stable PCB setup.

• Tests included:

  • Gesture accuracy,

  • Response time (avg < 500 ms),

  • Noise interference tolerance,

  • Load switching under AC conditions.

V. Results and Discussion

• Gesture recognition accuracy: ~94%.

• Sound recognition accuracy: ~91%.

• Response time: < 0.5 seconds.

• System stability: Maintained reliable operation over extended periods.

• Minor issues in noisy environments (for sound sensor) were observed, suggesting improved filtering in future versions.

• The system met its goals of being hygienic, safe, and user-friendly, suitable for smart homes and healthcare applications.

? Key Benefits

• Touch-free operation reduces contamination risk.

• Fast and accurate response with STM32.

• Low-cost and scalable design using common components.

• Ideal for modern automation needs with enhanced accessibility and safety.

Conclusion

This paper presented the design and implementation of a contactlessswitchsystemforcontrollingfourelectricalloadsusing gesture and sound-based inputs. The system demonstrated reliable performance, quick response, and hygienic operation without physical contact. By integrating simple sensors with an STM32 microcontroller, the solution offers a cost-effective and user- friendlyalternativetotraditionalswitches,particularlybeneficialin smart homes and sanitary-critical environments. Future improvements may focus on enhancing sensor accuracy under varying environmental conditions.

References

[1] Kalyavar. Win, M. A. Tun, andK. M. Tun, \"Design and Construction of InfraredRemoteControllerforMultipleHomeAppliances,\"International Journal of Scientific and Research Publications, vol. 8, no. 6, pp. 407– 411, June 2018. [2] AnkitJandial,S.Kumar,R.Butola,andM.K.Pandey,\"IRBased Home Appliances Control System,\" International Journal on Recent and InnovationTrendsinComputingandCommunication(IJRITCC),vol.5, no. 5, pp. [3] K. Druvitha and T. Deekshitha, \"Contactless Switch for Smart Home,\" International Journal of Scientific Research in Engineering and Management (IJSREM), vol. 5, no. 1, pp. 1–4, Jan. 2023. [4] Yegang. Du, Y. Tan, and Y. Lim, \"RF-Switch: A Novel Wireless Controller in Smart Home,\" 2018 IEEE International Conference on ConsumerElectronics-Taiwan(ICCE-TW),Taichung,Taiwan,2018,pp. 1–2, doi:10.1109/ICCE-TW.2018.8448687. [5] F.García-Vázquez,H.A.Guerrero-Osuna,G.Ornelas-Vargas,R.Carrasco-Navarro, L. F. Luque-Vega, and E. Lopez-Neri,\"DesignandImplementationoftheE-SwitchforaSmartHome,\"Sensors,vol.21,no.11,pp.1–17,2021,doi:10.3390/s21113811. [6] Thomas Okello, \"Design and Construction of a Four-Point Contactless Switch for Industrial Application,\" International Journalof Engineering ResearchandTechnology(IJERT),vol.9,no.7,pp.732–735,July2020.

Copyright

Copyright © 2025 Vansh Koli, Vaishnavi Naik, Shweta Pawar, Sarasvati Bailkar, Swapnil Jadhav. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.