INTRUSION ALARM WITH INDICATION OF PRIOR ACTIVATION

• US 3,833,895 A
• Filed: 12/29/1972
• Issued: 09/03/1974
• Est. Priority Date: 12/29/1972
• Status: Expired due to Term

• Current Assignee: Dennis E. Fecteau
• Original Assignee: Dennis E. Fecteau
• Inventors: Fecteau, Dennis E.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Lange, Richard P.
• Application Number:
  US05/319,679
• Time in Patent Office: 613 Days
• Field of Search: 340/152T,171R,171PF,276,224,408 325/51,57,55 343/6.5,6.8
• US Class Current: 340/505
• CPC Class Codes: G08B 19/00 Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow

Abstract

An alarm system including a sensing device for determining the status of a door and for transmitting a wireless signal to a receiver unit when the door is opened. The door unit can also be operated to initiate a delay mode by which the occupant can leave without activating an alarm. A portable unit can be carried by the occupant and used to either activate the alarm to summon help or to interrogate the system from without the protected space to determine its integrity during his absence. Window and fire sensing units can also be provided. The receiver is provided with means for distinguishing between the different signals transmitted by the hand-held and other units and also includes logic circuits responsive to trigger signals generated by receipt of various transmitted signals to perform different functions including sounding the alarm, sounding a different signal indicative of continued integrity, resetting, initiating delay modes to permit entrance and exit.

Claims

1. An alarm system comprising the combination of means for detecting an undesirable event and for transmitting a radio signal in response thereto on a first frequency;

an alarm;

means for receiving a radio signal on said first frequency and for actuating said alarm;

first manually operable means for resetting said means for receiving; and

portable means for generating a radio signal on a selected one of two frequencies, said portable means including second manually operable means for causing said portable means to transmit a signal at said first frequency, and third manually operable means for causing said portable means to transmit a signal at a second frequency;

said means for receiving further comprising means for receiving a radio signal at said second frequency and for generating an audible response signal only if a radio signal at said first frequency has not been received since the last operation of said manually operable means for resetting.

2. An apparatus according to claim 1 wherein said radio signal is frequency modulated.

3. An apparatus according to claim 2 wherein said means for detecting includes means for transmitting a radio signal at a third frequency and said means for receiving includes means responsive to a signal at said third frequency for delaying activation of said alarm for a predetermined interval.

4. An apparatus according to claim 1 wherein said audible response signal constituTes a signal of different audio characteristics from said alarm.

5. An alarm system comprising a protected space;

means for sensing a breach of the integrity of said protected space;

means for remembering that said integrity was breached;

means for resetting the system and thereby erasing said means for remembering;

means for transmitting an interrogation signal to said means for remembering from outside said protected space; and

means for responding to said means for transmitting if said integrity has not been breached.