Detection system with randomized transmissions

• US 4,734,680 A
• Filed: 02/06/1986
• Issued: 03/29/1988
• Est. Priority Date: 02/06/1986
• Status: Expired due to Fees

• Current Assignee: Notifier Company Lincoln Nebraska
• Original Assignee: Emhart Industries, Inc. (Stanley Black & Decker, Inc.)
• Inventors: Gehman, Stacy E., Ruddell, Kevin T., Dawson, Brian D.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US06/826,726
• Time in Patent Office: 782 Days
• Field of Search: 340/539, 340/531, 340/506, 340/505, 455/9, 455/53, 455/63, 455/67, 11/11, 364/717, 331/78, 331/64, 331/65
• US Class Current: 340/539.22
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G08B 29/14 checking the detection circuits

Abstract

A detection system having sending units for sending data signals representative of a condition, such as fire, smoke, intrusion, battery condition, or an emergency, to a central receiving unit. The sending units include a microcomputer which generates a pseudo-random number, waits for a number of cycle periods equal to the pseudo-random number, then activates a transmitter to send a data signal to the receiving unit. The randomized transmission prevents the synchronized clashing of transmitters.

Claims

1. A detection system comprising:

a plurality of sending units, each of said units comprising;

sensing means for sensing a condition;

means for generating a pseudo-random number;

means responsive to said sensing means and said means for generating for sending a data signal representative of said condition at pseudo-randomized time intervals, said means including a means for cycling through a number of timing loops in a microprocessor program equal to said pseudo-random number before outputting said data, and a means for delaying the sending of said data signal for a predetermined time interval in addition to the pseudo-random time interval; and

receiving means for receiving said data signals and producing an output indicative of said condition.

2. A method of providing an indication of a condition at a remote location comprising:

sensing said condition;

generating a pseudo-random number;

cycling through a timing loop in a microprocessor program a number of times equal to said pseudo-random number;

waiting for a predetermined time interval;

sending a data signal representative of said condition; and

receiving said data signal and utilizing it to provide an indication of said condition.