Freon is a coolant that is often used in systems such as air conditioners,
refrigerators and others. However, freon leaks can damage the environment
and endanger human health. In this study, a freon detector was designed and
implemented using the MQ-135 and MQ-139 sensors in a cold storage system. The purpose of this study is to provide early warning when a freon leak occurs. Therefore, it is important to have an effective detector in
detecting freon leaks. The MQ-135 and MQ-139 sensors were chosen as the
core components of the detector because of their ability to detect gas with a
good level of accuracy. In this design, both sensors are set to detect freon
leaks. During the implementation process, the author paid attention to the reliability and sensitivity aspects of the detector. The results showed that the
designed freon detector could detect freon leaks with high accuracy. Both sensors were able to detect freon leaks when the levels were more than 300 PPM. Based on the level of accuracy, the MQ-135 sensor had an error of
1.1%, while the MQ-139 sensor had an error of 0.8%. Based on the voltage
conversion, the MQ-135 recorded an average reading of 4.26 volts when gas
was present and 4.24 volts when gas was absent. Meanwhile, the MQ-139 recorded an average reading of 4.16 volts when gas was present and 3.96 volts when gas was absent. The test results showed that both sensors performed well, with an accuracy level close to that of the tested device. This device is expected to help detect freon leaks quickly and provide early warnings, thus maintaining user safety and minimizing negative impacts on
the environment.
Keywords: Detector Tools; Freon; Sensitivity ;MQ-139 Sensor;MQ-139
sensor