说明：  sim 900a 搭载火焰传感器水位传感器以及可燃气体传感器实时监测环境被测物理量，一旦出现灾情SIM900a将发送告警短信给目标手机号码
(SIM 900A carries the water level sensor of the flame sensor and the real-time monitoring environment of the flammable gas sensor to be measured in the physical quantity. Once the occurrence of the disaster SIM900a will send the warning message to the target cell phone number)