Abstract: An automatic light-intensity control system for greenhouses was proposed in the present study. The system adopted MSP430 as main control device. The designed I/V conversion circuit could convert the weak current signal outputted from silicon photocell to voltage signal. The differential amplifier circuit using two S1087 could effectively suppress temperature drift. Besides， the proposed system was able to send the measurement data to and receive commands from the monitoring center accurately via NRF905SE infrared wireless transmission module. After test， it was shown that the proposed control system could work stably. It was effective in suppressing temperature drift and thus possessed high precision within a large range of light-intensity. Also， the system could accurately transmit remote data， and therefore realize on-line remote control.

Key words: MSP430, silicon photocell, differential circuit, infrared wireless data transceiver