Gas flow output apparatus, disaster prevention monitoring system and automatic meter reading system

Disclosed is a gas flow output apparatus installed inside a gas meter, including a passive detection unit, a control unit, a wireless signal processor and an antenna. The passive detection unit includes a magnet and a magnetism reed switch. The magnet is installed on the surface of a gear inside the gas meter. The magnetism reed switch is installed to a location neighboring the gear. The magnet is rotated along with the gear and reciprocally moves close to and away from the magnetism reed switch, subjecting the magnetism reed switch to turn on or off by detecting whether the magnet is close to or away from the magnetism reed switch. The control unit is coupled to the magnetism reed switch, for sensing the state of on/off state of the magnetism reed switch, and then calculating flow data. The wireless signal processor is coupled to the control unit, processes the flow data as an RF signal, and wirelessly outputs the RF signal through the antenna. The gas flow output apparatus may be implemented in a disaster p