A MICROCONTROLLER BASED LED SUNPHOTOMETER WITH RF DATA ACQUISITION

A microcontroller based four-channel LED sunphotometer system with RF transceiver system was successfully developed in this study. The control and data acquisition was done wirelessly using a Zigbee RF Transceiver Module. The RF transceiver module was connected to the sun tracking mount and to a personal computer. Sun tracking was done using a quadrant photodiode for feedback control and a mathematical algorithm for tracking the sun for low-sunlight intensity situations. Eligh correlation coefficients were obtained when the data obtained from the four LED channels of the system was compared with a commercial four channel SP02 sunphotometer. With this system, the sun tracking mount can be placed anywhere without the need for long wires as long as there exists a line of sight between the two RF transceiver modules.