The hardware structure of a liquid level detection system for lead-acid battery was briefly introduced. The system adopts AT89C51 MCU as host module, combined with display storage, extended storage and the watch dog technology. The slave module adopts AT89C2051 MCU, which driver the linear CCD to realize non-contact measurement in acidic and corrosive conditions. The infrared transmission module uses RS-232 serial-to-infrared technology to realize wireless data delivery. The damage due to sensor corrosion could be avoided in this system. Compared with other similar equipments, this system has the advantages of simple structure, small volume, low cost, high measure precision and convenient maintenance.

According to high-voltage squirrel-cage AC asynchronous motor using string reactor to reduce voltage starting,there are some shortcomings such as circuit complexity, operation and maintenance trouble, the unfavorable to maintain and update and so on. Design of an intelligent explosion-proof electromagnetic starting reactor based on PIC16F887 microcontroller is proposed, this reactor has time type, current type, time-current starting type which can be set and it has temperature detection protection function in the starting process. After starting completion, it also has the bypass electrical locking function which can real-time monitor the current, voltage and temperature signals to realize intelligent. Using the reactor of controller already has been applied rated voltage 10kV, rated power 1600kW fan commissioning in a coal mine, the test results indicate that this reactor controls current smoothly in the starting process, and has reliable starting performance, easy operation, and high degree of intelligence.