The intelligent module is the execution unit and control end of the smart home platform. It is an organic whole and the intelligent control system is an organic whole. All kinds of intelligent modules are connected with intelligent central controller through wired or wireless mode. They accept the centralized control instructions of the central controller and constitute the whole smart home system platform with the central controller.

The intelligent module adopts PICl8F458 MCU to control [1], a power circuit, reset circuit, LCD/LED display circuit, RS interface circuit, 485 parameter circuit (EEPROM:Electrically Erasable Programmable Read save Only Mem - ory, EEPROM etc.), because the PICl8F458 contains ll bits MCU internal A/D conversion, so greatly simplifies the circuit design. The communication interface circuit of the intelligent module,

Module communication uses PICl8F458 internal asynchronous transceiver module and connects to RS 485 network after high-speed photocoupler isolation (6N137) and RS 485 drive circuit (65176). It must be noted that two power sources, VCC and 5V 2, which are used in the optocoupler circuit, must be completely isolated, otherwise the use of optocoupler will lose significance.

The RS 485 communication circuit uses the two level protection. G301, G302 and G303 are ceramic discharge tubes, and R311 and R312 are self recovery fuse. TVS1 and TVS2 are TVS tubes, which are selected according to the working voltage and voltage resistance of the chip, generally slightly higher than the highest working voltage of the chip, and can be selected between 6.8~10 V.

When lightning occurs, the induced voltage of both ends of the introduction of G302 and G303 are common mode protection, G301 differential protection, the over-voltage is reduced to about 500 V, after R311, R312 TVSl TVS2, current limiting, two pressure limit, the voltage is clamped to the transceiver in the 6.8 V left and right in order to achieve the protection of the RS, a 485 drive circuit.