Development of an Electronic Photo Sensor for Chlorophyll Detection

Abstract

The amount of chlorophyll in plant leaves can be measured using time-consuming and challenging traditional chemical procedures; alternatively, highly expensive sensor-based meters are available in the market. In this paper, the design of an inexpensive, less complex, optimum-sized ESP-32-based electronic chlorophyll reader is presented. For the suggested electronic reader the design of the photosensor circuit is the primary focus of the study. It includes designing current amplifier circuits for photodetectors and LED driver circuits for red and infrared LEDs. Spectral absorption by leaf chlorophyll is the parameter used for measuring chlorophyll. Regarding leaf chlorophyll spectral absorption, red LEDs are the most absorbing. Utilizing this function, red LED spectrum absorption measurements are made for various plant leaves. The chlorophyll content of the same leaves is then determined in the botany lab using Arnon's method. To confirm the photosensor design, the red LED spectrum absorbance and the chlorophyll identified using Arnon's technique are analyzed for different leaves. The photosensor is verified to be operating correctly. Additionally, a linear regression model for performance analysis is provided.