Automatic Electronic Control of the Level of LPG in air in a Confined Space

Documentation of the automatic electronic control of the level of LPG in air in a
confined space can be viewed in this project. Humans are increasingly becoming
dependent on petrochemical products for their daily life. Ignition of these
combustible products can have catastrophic effect especially in a confined space
where there exist limited amount of air. Therefore, a sensor is needed to monitor the
level of gases in homes and also in industry to avoid all possibilities of the accidents.
The aim of this project is to design an automatic electronic control of the level of
flammable gases in a closed chamber as one of the solution in curbing the
concentration of these gasses from increasing in air and reaching its lower explosive
limit (LEL). Literature review was done in order to select the suitable sensor and the
appropriate circuit. Some lab work was also conducted to verifY all the findings and
simulate the circuit designed.
After simulation, the circuit was designed and tested on breadboard. Graphs of
voltage changes versus time and when exposed to gas was plotted. From detailed
analysis using the spreadsheet provided, it was demonstrated that the sensor is very
sensitive and its response time is less than a minutes. The circuit is demonstrated to
be working once the sensor is to be working once the sensor is exposed to the gas by
actuating a venting fan. A prototype sensor circuit is finally designed and tested.