Light Measurement System Project

Project Overview

The Light Measurement System Project is designed to enhance safety and visibility on a jungle gym located in a park in Johannesburg, South Africa. This system automatically activates additional lighting when natural illumination is insufficient, ensuring the play area remains safely lit during periods of low light. This enhances safety for children using the jungle gym.

Project Components

• PIN-Photodiode Sensor: Measures light levels and controls the lighting system.
• Transimpedance Amplifier: Converts photodiode current into a measurable voltage.
• Low-Pass Filter: Reduces high-frequency noise for more accurate measurements.
• ATmega328P Microcontroller: Handles sensor data processing and system controls.
• LCD Display: Offers a real-time display of light levels and system status.

Part 1: Initial Design and High-Level Solution

Implementation on Jungle Gym

Design modifications to the jungle gym ensure no interference from children and optimal exposure to light. Features like a flat roof for equipment and inclined surfaces for water runoff were implemented.

Refer to the Annotated Figure of the Jungle Gym in Figure 1 of the Measurement Systems Project Report 1.

Design Requirements

Part 1 of the project further focuses on the design specification of the system to address the environmental conditions of Johannesburg. Key aspects such as the visible light spectrum (380-700 nm), system responsiveness, and accuracy were considered.

Refere to Table 1 of the Design Specifications in Measurement Systems Project Report 1.

Proposed High-Level Solution

The proposed high level solution in part one takes into account:

• Analysis of the Input Signal: Analysis of the measured variable in both the Time and Frequency Domains, refer to Figure 1 and 2 in Measurement Systems Project Report 1.
• Review of Existing Solutions: Both a review and comparison of existing solutions is shown in Table 2 in the and their comparison in Table 3 in Measurement Systems Project Report 1.

Part 2: Detailed Design and Performance Evaluation

Detailed System Design

Part two delves deeper into the electronic design, featuring detailed circuitry and microcontroller logic to ensure precise measurement and control:

• Photodiode Characteristics: Detailed modeling captures the required light intensity.
• Signal Conditioning: Handled by a transimpedance amplifier for current-to-voltage conversion.
• Signal Processing: A low-pass filter ensures the fidelity of the signal by attenuating noise.
• Microcontroller Logic: Manages complex signal processing and control algorithms.

Check the Logic Flowchart and Complete Annotated Circuit Diagram in Figure 2 and Figure 4 of the Measurement Systems Project Part 2.

Performance Evaluation

The system's performance was rigorously evaluated through simulations and empirical testing:

• Transfer Function and Bode Plot: MATLAB simulations validate the dynamic response and ensure adherence to design specifications.

Refer to the Bode Plot in Figure 3 of the Measurement Systems Project Part 2.

Conclusion

This project effectively demonstrates the application of advanced measurement and control techniques to enhance child safety in public play areas. The sequential design process, from initial conception to detailed implementation, ensures that the system meets the specific needs of its intended environment and operational demands.