Hardware Developments for Fruits and Vegetables Quality Determination

Traditionally, for fruits and vegetables quality assessment are determined by the
physical characteristics such as colour, shape and firmness. In this research, an
electronic nose will be used to determine the freshness state of tomatoes. And the
electronic nose is a combination of three different types of gas sensor. The electronic
nose detects the aroma produced by the tomatoes before analyzing it into its stage of
ripeness. Then the electronic nose will then categorize it into three different states;
fresh, slightly fresh and rotten based on the results obtained from the sensors. Before
the experiments can be started, suitable types of sensors should be chosen and tested
separately to ensure it is working well. By observing the output waveforms between
normal conditions with a fresh fruits, it shows a slight change in terms of the voltage.
Therefore it is safe to say that during the process of ripeness, the fruits actually
produce gas and it is detected by the sensors. During the fresh condition and also
rotten condition, we can also see the differences in terms of the voltage. One of the
sensors, even during the rotten condition, the voltage across the load resistance
increases. But for the other two sensors, during the fresh condition, the voltage it
obtains increases however during the rotten condition, the voltage drops. Therefore,
it is feasible to say that the electronic nose can detects whether the fruit is fresh or
rotten by observing the changes in all three sensors.