Kızılberisi algılayıcılarla uçucu organik bileşenler kaçağı tespiti

Advances in technology and industry leads to a rise in the living standards ofpeople. However, this has also introduced a variety of serious problems, suchas the undesired release of combustible and toxic gases which have become anessential part of domestic and industrial life. Therefore, detection andmonitoring of VOC gases have become a major problem in recent years. In thisthesis, we propose novel methods for detection and monitoring VOC gas leaksby using a Pyro-electric (or Passive) Infrared (PIR) sensor and a thermopilesensor. A continuous time analog signal is obtained for both of the sensors andsent to a PC for signal processing. While using the PIR sensor, we have HiddenMarkov Models (HMM) for each type of event to be classified. Then, by usinga probabilistic approach we determine which class any test signal belongs to. Inthe case of a thermopile sensor, in addition to Hidden Markov Modelingmethod, we also use a method based on the period of the sensor signal. Thefrequency of the output signal of the thermopile sensor increases with thepresence of VOC gas leak. By using this fact, we control whether the period ofa test signal is below a predefined threshold or not. If it is, our system triggersan alarm. Moreover, we present different methods to find the periods of a givensignal.