Over the last decade, metal oxide semiconductor gas sensors have been very useful in the areas of pollutant monitoring, diagnosis, process control and personal safety. Most microelectronic devices use metal oxide semiconductor sensors because they are relatively cheap to produce. They are highly sensitive, and their small size made it applicable in several industrial fabrications. The functionality of semiconductor gas sensor is based on oxidation or reduction which are both function of conductivity or resistivity respectively. Overtime semiconductor gas sensors have been the best choice for gas detection.
The structural stability of MOS sensors have been maintained through the integration of material sensors, this will also improve the…show more content… There is a need to develop a device that can separate infected and healthy onion through their smell.
The electronic nose innovation offers a different approach to gas detection in a quick and non-dangerous way. The possibility of Enose was first proposed by scientists from warwick college in mid 1980s. the idea use three metal oxide gas sensors to recognize smells and scents. Most gas sensors incorporate metal oxide, polymer, acoustic wave and MOSFET. Metal oxide sensors are largely insensitive to humidity due to the fact that they are operated at high temperature. We also have the zNose which is based on surface acoustic wave (SAW) sensor. It identifies volatile compounds by detecting the mass change in a piezoelectric impact. The eNose has been widely used to examine food quality and to predict expiration date of food. For example, the eNose innovation has been turned out to be viable in identifying decay in different processed food such as bread, wheat, hamburger, poultry feed, and grains.
The development of enose requires a combination of volatile sampling, sensing, data recording, data analysis. Technically, the idea and system used to develop this project could be adjusted to meet the requirement for post-harvest diseases detection especially for perishable farm produce.
System overview the general objective of this work is to build up a modified gas sensor for onion post-harvest