Development of a Portable Spectrometer for Ripeness Characterization in Oil Palm Fruit

Current detection of ripeness of oil palm fruit are using human eyes and sensors which are non-portable. Raman LiDAR is a good device to identify the ripeness of oil palm fruit in which it is a non-destructive method that produces a more accurate result. The main objective of this project is to create a portable spectrometer with the mission to identify the ripeness of oil palm fruit. This initiative is relevent to the plantation owner because it is important for them to harvest the oil palm fruit at the right time. If they are able to identify the ripeness with the help of a portable Raman instrument, it will significantly improve their harvest product. In this project, spectrometer is built as a receiver part to obtain the spectrum image from different light sources. Each optic components is stabilised by 3D printing customised holders and optical breadboard. Diffraction grating will separate the wavelength of light which is then focused by the mirrors. Next, webcam is used to capture the spectrum image to be processed in Matlab. Red, green and violet lasers are used as the light source because of its large penetrating power with high frequency. Along the project implementation process, it is found that Crossed-Czerny Turner is the most suitable technique to reduce stray light emission. The result obtained is in the form of graph of intensity vs pixel for the light sources tested. Resolution of spectrometer is identified at the end of the experiement. With the use of this portable Raman Spectrometer, weak Raman signal obtained from different fruit is possible to be captured for characterisation. With this, it is believed that the spectrometer will act as a receiver and processor for the Raman LiDAR.