Air Filter Alarm System to Prevent High Energy Consumption- Researching Sensors
The second major task for this research project was to find a sensor that could be used to detect when the air filter needed to be changed. This proved to be a lengthy process since there were so many types of alarms to consider. First, infrared emitters and detectors were researched to see if they could be used. This idea was discarded once it was found that the sensor could only detect when there was a definite blockage in its path, not when there was only some degree of blockage as is the case with a dirty air filter. Secondly, ultrasonic detectors were considered to measure the thickness of the clogging on the air filters, but this would be a very expensive type of sensor and not very practical for the needed application.[3] Thirdly, pressure sensors were considered to measure the pressure difference from one side of the air filter to the other. Although this could be an effective type of sensor for this application, it would be hard to simulate within a lab the actual pressure changes of a house due to things such as opening and closing of doors, therefore this idea was also discarded.[4] Finally, a cadmium sulfide photocell was considered and found to be the best sensor for the given job. A cadmium sulfide photocell is simply a light dependent resistor. When more light falls upon the photocell, the resistance decreases and when less light falls upon the photocell, the resistance increases. TAGUTI Air Filter suppliers
