Circadian rhythm is a biological rhythm that has a period of 24 hours. Leaf movement is one of physical indicator that commonly used to detect the circadian rhythms in the plant. In its application, it is required to design a plant motion monitoring system that can work automatically and continuously to estimate the period of plant motion and quantify the circadian rhythm. Generally, a plant monitoring system uses a top view projection to monitor plant activity. To extend its functionality, the side view projection was also important to monitor the plant behavior from a horizontal point of view. The objective of this study was to design and evaluate the performance of the Top and Side view projection as multi-camera for continuous plant motion monitoring system. The system composed of two IR LED cameras with Top and Side view projection and connected to the microcomputer (Raspberry Pi3 B+). The data were analyzed by Optical Flow method using OpenCV Library applying Shi-Tomasi and Lucas Kanade. Estimation of circadian rhythms was using the FFT (Fast Fourier Transform) method. The multi-camera system was evaluated to monitor the motion of Chili (Capsicum annum L.) by observing the time series of circadian rhythm, Period, Amplitude, and Phase. As a result, the system could be used to monitor the circadian rhythm for both Top and Side view projection. The Frequency and Period have the same value 0,00001157 and 24-hour. The Top view projection has higher amplitude means, for the same object motion it could represent clear motion. © 2019 Author(s).