Waste Material Classification: A Short-Wave Infrared Discrete-Light-Source Approach Based on Light-Emitting Diodes

Area of Science:

• Materials Science
• Environmental Engineering
• Optical Engineering

Background:

• Effective waste material classification is crucial for efficient waste management and recycling.
• Current systems often face challenges in cost and complexity.
• There is a growing need for accessible and affordable waste segregation technologies.

Purpose of the Study:

• To develop a simple, compact, and low-cost waste classification system.
• To utilize optical reflectance measurements in the short-wave infrared spectrum for material segregation.
• To demonstrate a practical solution for identifying common waste materials.

Main Methods:

• The system employs a minimal set of Light Emitting Diodes (LEDs) and a single broadband photodetector.
• Optical reflectance measurements were taken in the short-wave infrared range.
• Low-cost, low-power electronics controlled the system, with data managed via a computer interface.

Main Results:

• The classification system achieved up to 94.3% accuracy for seven distinct waste materials.
• Excluding the most challenging materials, accuracy increased to 97.0%.
• The system successfully segregated plastics, paper, glass, and aluminium.

Conclusions:

• The developed optical reflectance system offers a viable low-cost solution for waste material classification.
• This proof-of-concept demonstrates potential for future advancements in automated waste management.
• The system's simplicity and effectiveness make it suitable for widespread adoption.