| 摘要 |
<p>PURPOSE:To prevent burglary without fail by generating a warn when prescribed time is passed after a detection signal from an optical sensor is changed from bright to dark or when the signal exceeds a prescribed frequency in the case that vibration is detected by a vibration sensor. CONSTITUTION:An entrance/exit, etc., at a place, where a burglar preventing machine 1 is always set up, is lighted up by turning on/off light with more than a prescribed frequency different from a commercial frequency. In the case that the vibration is detected by a vibration sensor 13, the burglar preventing machine 1 decides the burglar and generates the warn when the prescribed time is passed after it is detected by an optical sensor 5 that the light is changed from bright to dark, or when the light more than the fixed frequency is detected by the optical sensor 5. Then, the warn is also generated when a commodity 3 is pulled out from a clear case 2 by a microswitch 4. Thus, the robbery can be prevented without fail and an equipment to radiate strong electromagnetic waves is not required. Then, the machine is out of the adaptation of a wave low and a resonator to detect the electromagnetic waves is not required. Accordingly, the external form of the machine is made compact.</p> |
