COMBUSTIBLE GAS CONCENTRATION DETECTOR

V diplomskem delu je opisana zgradba in delovanje pomembnejših elementov v vezju. Plinski merilnik koncentracije metana temelji na katalitični detekciji z uporabo Pellistor elementa. Senzor MQ2 deluje s pomočjo mikrokrmilnika Arduino Leonardo. Programska koda mikrokrmilnika s katero smo izvedli izpis koncentracije plina na zaslon in samega delovanja senzorja je tudi podrobno opisana. Cilj naloge je bila izdelava merilnika koncentracije metana. Ko merilnik zazna dovolj veliko koncentracijo plina, sproži alarm. Prav tako je tudi predstavljen proces načrtovanja in izdelava tiskanega vezja. Sem spada risanje električne sheme in tiskanega vezja. Potrebna je bila pravilna izbira elementov za diferenčni ojačevalnik pri katerem smo imeli največ zapletov, predvsem zaradi tega, ker smo morali uporabiti dvojno napajanje in stabilizirati vhodne napetosti ojačevalnika. Izhod MQ2 je povezan na ojačevalnik, ki skrbi za primerni napetostni nivo na vhodu mikrokrmilnika. Programska koda je napisana v Arduino okolju, ki uporablja programski jezik C.The thesis describes the structure and operation of the most important elements in the circuit. The methane gas meter is based on catalytic detection using a Pellistor element. MQ2 sensor works with Arduino Leonardo microcontroller. The program code of the microcontroller, which was used to show the gas concentration on the LCD and the operation of the sensor itself, is also described in detail. The aim of the assignment was to create a methane concentration sensor. When the sensor detects a high gas concentration, it triggers an alarm. The process of designing and manufacturing a circuit board is also described. It includes drawing electrical diagrams and circuit boards. It was necessary to correctly select the elements for the differential amplifier, where I had the most complications, mainly because we had to use a dual power supply and stabilize the input voltages of the amplifier. The output of MQ2 was connected to the amplifier, which amplifies sensor voltage to the appropriate voltage level at the input of the microcontroller. The program code was written in the Arduino environment, which uses the C programming language