Sensing device for detecting alarm bell of siren

摘要

A sensing device (10) for detecting an alarm bell of a siren (50) includes a sound sensor (11), a signal filter (12), a signal amplifier (13), a microprocessor (14) and a signal transmitter (15). The sound sensor (11) detects the alarm bell of the siren (50) to generate a first sound signal. The signal filter (12) is connected to the sound sensor (11) to filter noises of the first sound signal. The signal amplifier (13) is connected to the signal filter (12) to amplify the first sound signal. The microprocessor (14) is connected to the signal amplifier (13), and the microprocessor (14) receives and compares the first sound signal with a second sound signal to output a decision signal. The signal transmitter (15) is connected to the microprocessor (14) and receives the decision signal to output an alarm bell signal.