HOTEL_ROOM_ALARM

Published:2009/7/1 22:07:00 Author:May | From:SeekIC

Alarm mounted in flashlight-shaped cylinder is positioned on floor inside hotel room in such a way that it is knocked over by intruder opening door. Mercury switch S2 then triggers SCR and activates Mallory SC-628P pulsed Sonalert alarm. Circuit latches on and can be tumed off only by use of Darlington-amplifier touch switch. Connection from base of Darlington to positive terminal of battery must be made through fingertips as shown by dashed line in orderto silence alarm. Once silenced, S1 can be opened to disconnect latch so alarm can be moved. Other applications include protection of unattended luggage. C1 is 0.1 μF, R1 is 1 megohm, R2 is 1K, R3 is 39K, and S2 is mercury element removed from GE mercury toggle switch,-R. F. Graf and G. J. Whalen, The Build-It Book of Safety Electronics, Howard W. Sams, Indianapolis, IN, 1976, p 19-24.



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