BURGLAR DETERRENT TIMING SWITCH

• US 3,713,126 A
• Filed: 02/18/1971
• Issued: 01/23/1973
• Est. Priority Date: 02/18/1971
• Status: Expired due to Term

• Current Assignee: Joseph C. Stettner
• Original Assignee: Joseph C. Stettner
• Inventors: Stettner, Joseph C.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Slobasky, Michael
• Application Number:
  US05/116,331
• Time in Patent Office: 705 Days
• Field of Search: 340/258R,258D,276,261,377,322 307/293
• US Class Current: 340/527
• CPC Class Codes: G08B 13/1672 using sonic detecting means, e.g. a microphone operating in the audio frequency range
• CPC Class Codes: G08B 15/002 with occupancy simulation

Abstract

A burglar deterrent having a timing switch connected to the lights of a room or building for actuating these lights for a selected period of time in response to a sound made by an intruder. The timing switch has an SCR connected to the switch terminals. The gate of the SCR is connected to a timing circuit which comprises a series connected capacitance and diode connected from the gate to the anode of the SCR. A second SCR has its main terminals connected across the capacitance for, at times, discharging the capacitance in response to a trigger signal at the gate of the second SCR. A zener diode is connected for limiting the charging voltage applied to the capacitance. A variable resistance is connected from the gate of the first SCR to its cathode to permit selection and control of the delay time.

Claims

1. An intruder deterrent for actuating an illumination means for a selected period of time in response to a sound, said deterrent comprising:

a. a sound transducer and amplifier means for picking up said sound and converting it to an audio trigger signal; and

b. a timing switch means connected in series to said illumination means and to a source of AC power therefor, said timing switch means having a trigger input terminal connected to the output of said transducer and amplifier means, for actuating said illumination means for a selected period of time in response to an occurrence Of said audio trigger signal and for then automatically deactuating said illumination means said timing switch means further comprising;

1. an electronic switch having its main terminals connected at the switch means terminals and having a control input terminal;

2. a timing circuit comprising a series capacitance and rectifier connected between said control terminal and a source of AC control input power at one of the main terminals of said switch means, the rectifier being polarized to permit control input current flow for charging said capacitor by time spaced current pulses through said control input; and

3. capacitance discharging means including an electronic switching device connected across said capacitance for at times discharging the capacitance in response to said triggering signal.

2. a timing circuit comprising a series capacitance and rectifier connected between said control terminal and a source of AC control input power at one of the main terminals of said switch means, the rectifier being polarized to permit control input current flow for charging said capacitor by time spaced current pulses through said control input;

and

3. capacitance discharging means connected across said capacitance for at times discharging the capacitance in response to said triggering signal wherein said capacitance discharging means is a second thyristor having its main terminals connected across said capacitance and having its gate connected to receive said triggering signal.

4. An intruder deterrent according to claim 3 wherein said first thyristor and said second thyristor are silicon controlled rectifiers and said timing circuit is connected to the anode terminal of said first thyristor.

5. An intruder deterrent according to claim 4 wherein a variable resistance is connected between the gate terminal and the cathode of said first thyristor for control of the time delay of said timing circuit.

6. An intruder deterrent according to claim 4 wherein a zener diode is connected between a node of said timing circuit and the cathode terminal of said first thyristor for limiting the voltage applied to the capacitance.

7. A timing switch according to claim 6 wherein a variable resistance is connected between the gate terminal and the cathode terminal of said first thyristor for control of the time delay of the time delay of said timing circuit.

8. A timing switch according to claim 7 wherein the zener voltage of said zener diode is relatively small compared to the maximum instantaneous voltage at the main terminals of said first thyristor.

9. An intruder deterrent according to claim 3 wherein a. a triac has its principal terminals serially connected to said load and to said source of power and has a control gate terminal;

b. a bridge rectifier circuit is connected at its bi-directionaL nodes to said gate terminal and a principal terminal of said triac;

c. said timing switch is connected to the uni-directional nodes of said bridge rectifier circuit; and

d. a power supply filtering circuit has its input connected to the uni-directional nodes of said bridge rectifier and its output connected to a power supply terminal of said transducer and amplifier means;

whereby said timing switch controls the firing of said triac and said amplifier is disabled when said timing switch is on.

10. An intruder deterrent according to claim 3 wherein a manual switch is connected parallel to said timing switch for manual illumination of said illumination means and for automatically making said timing means operable when said manual switch is opened.