第3个回答 2015-05-10
The alarm system set out in their state. When someone broke into, pyroelectric infrared sensor to detect movement, set on the monitoring of infrared probe human radiation of infrared spectrum transform into electrical signals, amplifying circuit, compare circuit, to the threshold switch, open the threshold valves out TTL level to AT89C51, driven by single chip microcomputer after processing operations performed alarm circuit warning voice.