Document Type

Conference Paper

Publication Date


Publication Title

2003 ASEE Annual Conference Proceedings



Conference Name

2003 ASEE Annual Conference and Exposition, Nashville, Tennessee


This paper presents a successful senior project of instrumentation developed in a Mechanical Engineering Technology senior capstone course. Students were encouraged to approach the problem of designing an air-filter sensor and to propose an optimum and practical solution for the problem. Work includes conceptual design and analysis, implementation, tests and modifications. When an air filter is used in a home air conditioner, inhabitants often forget when to replace it until the cooling or heating capacity is obviously reduced. If the filter remains in service, the efficiency of the cooling/heating system will continue decreasing while the electricity bill will significantly increase. In some worst cases, the air quality will also be affected. This paper presents an idea of designing and fabricating an air-filter sensor to alleviate this problem. The sensor will send a warning signal when the filter collects a specific amount of dust in the air filter. It can be easily installed and only consumes a negligible amount of electricity. A photo sensor with an infrared LED emitter and receiver is used in this design. As the infrared LED can transmit through most of the home-used air filter to its receiver, a signal will be sent out when a specified amount of dust is collected in the filter and the light is blocked from the emitter to the receiver. The emitter and receiver are mounted on a simple fixture and can be easily fitted on an air filter. In addition, cost analysis of using the sensor show that it can save a significant amount on an electricity bill, when filters are replaced properly.


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Original Publication Citation

Lin, C. Y., Crossman, G. R., & Verma, A. K. (2003). An air-filter sensor for home-used air conditioners. Paper presented at the 2003 ASEE Annual Conference Proceedings, Nashville, Tennessee.