clap activated light switch

The Challenge

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Turning off the bedroom light before bed can be inconvenient, especially when the switch is across the room. The goal was to create a hands-free lighting control system that could be operated from anywhere in the room.

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Requirements:

• The system needed to detect at least three different inputs and produce at least two distinct motor behaviors.
• It had to incorporate at least one sensor and use an Arduino UNO for processing.

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Design Objectives

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The objective was to develop a simple yet effective mechatronic system that:

• Enables hands-free control of bedroom lighting.
• Utilizes an intuitive and reliable activation method.
• Is easy to install and modify for future improvements.

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The Solution: Clap-Activated Light Switch

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A sound-sensitive system that allows users to control their bedroom lights with simple claps:

• One clap turns the light off.
• Two claps turn the light on.

This solution provided a seamless, contactless way to manage lighting from anywhere in the room.

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Exploring Possibilities

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Several sensor options were considered to achieve the desired functionality:

• Ultrasonic Sensor: Detect movement toward or away from the switch.
• Infrared Motion Sensor: Detect general motion in the room.
• Microphone Sensor: Detect sound patterns as triggers.

After evaluating these options, the microphone sensor was chosen as it allowed activation from any location in the room, aligning best with the project’s goals. A servo motor was selected to physically flip the light switch.

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Prototyping & Implementation

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• Built a circuit with a microphone sensor to detect claps, initially tested using an LED indicator.
• Processed sound input by smoothing data and setting an appropriate volume threshold.
• Integrated a servo motor to translate the detected claps into physical movement.
• Mounted the servo onto an existing light switch using cardboard and craft stick extensions.
• Designed a custom switch cover to integrate the servo more seamlessly.

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System Workflow

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1. Microphone sensor detects claps (one, two, or none).
2. Servo motor rotates counterclockwise for one clap (turning the switch off).
3. Servo motor rotates clockwise for two claps (turning the switch on).

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Key Learnings

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• Sensor Data is Noisy: Raw sensor readings require filtering, such as averaging or thresholding, to ensure accurate and meaningful inputs.
• Integration Matters: A well-designed physical system is crucial to ensuring smooth interaction between hardware and software.
• Iteration is Key: Testing and refining both the code and mechanical components together help prevent misalignment between expected and actual behavior.

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Conclusion

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This project demonstrated the effectiveness of a mechatronic system for automating home lighting. By leveraging sound-based activation and a simple servo motor mechanism, the design provided a user-friendly and adaptable solution. The project also highlighted the importance of sensor reliability and iterative development in creating functional home automation systems.

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