Design of thermohygrometer with control function based on MSP430F149

FU Huayuan, ZOU Hongbo, LU Renquan
(Institute of Information and Control, Hangzhou Dianzi University, Hangzhou 310018, China)

Abstract: Aiming at solving the problems of single function, short battery life and no use in network for old thermohygrometer, a new thermohygrometer with control function based on MSP430F149 singlechip was presented. The sensor interface circuits, power circuit and RS232/RS485 communication circuit on the board were designed newly compared with other similar instruments, and so the problems on these circuits were solved in the new instrument. In addition, some extended functions were provided, like the circuit for receiving and converting 4 mA~20 mA current, real-time clock circuit, single relay control board and so on. The program was discussed in the end, it consisted of main program design, interrupt programs design, program design for RS232/RS485 communication and other subfunctions design. The results indicate that the device has basic measurement function and control function through independent testing and networked testing, and other functions can be expanded by users, it is convenient in use and stable in performance.
Key words: MSP430F149; multiple interfaces; RS232/RS485; low power consumption