Alarm triggering circuit

• US 4,016,537 A
• Filed: 06/21/1976
• Issued: 04/05/1977
• Est. Priority Date: 07/14/1975
• Status: Expired due to Term

• Current Assignee: Richard V. Ray
• Original Assignee: Richard V. Ray
• Inventors: Ray, Richard V.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/697,996
• Time in Patent Office: 288 Days
• Field of Search: 340/63, 340/64, 340/276, 307/10 AT, 180/114
• US Class Current: 340/430
• CPC Class Codes: B60R 25/1003 Alarm systems characterised by arm or disarm features

Abstract

The present invention is an alarm triggering circuit for use in an alarm system for a motor vehicle having an alarm, a power source and an ignition system that provides a positive voltage when it is turned on and a ground when it is turned off. The alarm triggering circuit includes an alarm setting circuit which sets the alarm triggering circuit and a delaying circuit which enables an operator of the mot or vehicle to exit it. The setting circuit includes a first timer chip whose output is normally positive and a first transistor which when it is turned on provides a ground to the input terminal of the first timer chip. When the ignition system is turned off, the first transistor is turned off thereby causing the output of the first timer chip to go to ground. The delaying circuit includes a capacitor in series with a variable resistor and is electrically coupled to the alarm triggering circuit which includes a second timer chip whose ground terminal is electrically coupled to the output terminal of the first timer chip and a second transistor whose base is electrically coupled to the output terminal of the second transistor and which is electrically coupled to the alarm so that when it is turned on by the output of the second timer chip the alarm will sound.

Claims

1. In an alarm system for a motor vehicle which has a power source, an ignition system that provides a positive voltage when it is turned on and a ground when it is turned off, an alarm such as a horn or a siren, an alarm relay which is electrically coupled to the alarm, and a set of tampering switches which provide a ground when the motor vehicle is being entered into or tampered with by a would be thief, an alarm triggering circuit comprising:

a. alarm triggering means for providing a ground to the alarm relay thereby activating the alarm;

b. delaying means for providing a signal from the set of tampering switches to said alarm triggering means; and

c. setting means for setting said alarm triggering means when the ignition system is turned off, said setting means including;

3. In an alarm system for a motor vehicle an alarm triggering circuit according to claim 1 wherein said delaying means comprises:

a. a second transistor having a base, an emitter and a collector, said second transistor is of the type that is turned on by a ground signal to its said base and it has its collector electrically coupled to any tampering switch which provides a positive voltage signal and its base electrically coupled to the set of tampering switches providing a ground signal;

b. a second capacitor of a second particular capacitance being electrically coupled to said collector of said second transistor and to said output terminal of said first timer chip; and

c. a variable resistor electrically coupled to said collector of said second transistor and to said alarm triggering means.

2. a first timer chip having a trigger terminal, a reset terminal and an output terminal and being electrically coupled to the power source of the motor vehicle;

2. a first resistor of a first particular resistance being electrically coupled to the ignition system;

3. a first transistor having a base which is electrically coupled to said first resistor, an emitter which is electrically coupled directly to ground, and a collector;

4. a first diode electrically coupled to said trigger terminal of said first timer chip and to said collector of said first transistor;

5. a first capacitor of a first particular capacitance electrically coupled to ground and to said trigger terminal of said first timer chip;

6. a second resistor of a second particular resistance being electrically coupled to said trigger terminal of said first timer chip; and

7. a switch being electrically coupled to the power source of the motor vehicle and to said second resistor.

4. In an alarm system for a motor vehicle an alarm triggering circuit according to claim 2 wherein said alarm triggering means comprises:

a. a second timer chip having a trigger terminal, a reset terminal, a discharge terminal and an output terminal and being electrically coupled to the power source and to said output terminal of said first timer chip, said output terminal of said second timer chip is electrically coupled to said emitter of said second transistor;

b. a third transistor having a base, an emitter and a collector and being of the type which is turned on by a ground signal, said emitter of said third transistor being electrically coupled to the alarm relay, said collector of said third transistor being electrically coupled to ground, and said base of said third transistor being electrically coupled through a diode to said output terminal of said second timer chip; and

c. a third resistor of a third particular resistance electrically coupled to said discharge terminal of said second timer chip and to said collector of second transistor.