BURGLAR DETERRENT TIMING SWITCH

• US 3,761,912 A
• Filed: 05/20/1971
• Issued: 09/25/1973
• Est. Priority Date: 05/20/1971
• Status: Expired due to Term

• Current Assignee: James H. Ott, Joseph C. Stettner
• Original Assignee: James H. Ott, Joseph C. Stettner
• Inventors: Stettner, Joseph C., Ott, James H.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Partridge, Scott F.
• Application Number:
  US05/145,134
• Time in Patent Office: 859 Days
• Field of Search: 340/258B,258,276,148,309.1,258D,261,331 307/252B,252W,117
• 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

Abstract

A burglar deterrent switch for installation in a conventional manual switch box for controlling room lights. An electronic sound responsive timing switch illuminates the room lights for a selected period of time in response to the occurrence of a sound and then turns the lights off for another selected period of time. The timing switch has a triac which is shunted across the manual light switch. The gate of the triac is controlled by an SCR connected in a bridge rectifier for controlling the triac gate current. The gate of the SCR is connected to the output of an amplifier and is switched on by sound incident upon a sound transducer connected to the input of the amplifier. A timing circuit means is also connected across the SCR and comprises a pair of voltage reference diodes connected parallel to a capacitance for fixing the voltage to which the capacitance may charge and having a resistance series connected to the parallel diodes and capacitance.

Claims

1. An electronic timing switch for controlling the power applied to a load which is connected to said switch and to a source of electrical power, in response to a non-periodic input actuating signal, said switch comprising:

a. a first electronic switch for switching the current in said load, the first electronic switch having a control gate;

b. a second electronic switch in the gate circuit of the first electronic switch connected to a source of gate current for switching the gate current of said first electronic switch, the second electronic switch having a control gate;

c. a coupling circuit means for coupling an externally generated, non-periodic input actuating signal to the gate of said second electronic switch;

d. timing circuit means connected across the main terminals of said second electronic switch for controlling the operation of the first electronic switch and for providing a voltage to selectively enable and disable the coupling means, the timing circuit means comprising a plurality of series connected voltage reference diodes connected parallel to a capacitance and having a resistance series connected to said parallel connected capacitance and series diodes, said enablingdisabling voltage occurring across one of said voltage reference diodes and said coupling means connected across said one diode for being selectively enabled and disabled.

2. an electronic timing switch connected to said illumination means and a source of power for switching the current in said illumination means to illuminate said illumination means for a selected period of time in response to a sufficient sound and then for subsequently blocking the current through the illumination means for another selected period of time wherein:

said timing switch comprises a. a triac, the main terminal of which are the switch terminals, for switching the current in said load;

b. a bridge rectifier connected at its opposite bi-directional nodes between the gate of said triac and the main terminals of the triac for switching the gate current of the triac;

c. an SCR having its main terminals connected to the opposite uni-directional nodes of said bridge rectifier in a direction to, at times, permit substantial current flow between said uni-directional nodes;

d. an amplifier means having its output connected to the gate of said SCR for firing said SCR in response to the presence of said input actuating signal at the input of said amplifier;

e. a timing circuit means connected across said SCR and comprising a plurality of series connected, similarly polarized voltage reference diodes parallel connected to a capacitance for fixing the voltage to which the capacitance may charge, and having a resistance series connected to said parallel connected diodes and capacitance the total zener voltage of said diodes being less than the peak, instantaneous voltage across the SCR, the biasing supply terminals of said amplifier being connected across one of said voltage reference diodes for supplying power to said amplifier; and

f. a sound transducer connected to the input of said amplifier.

3. A switch according to claim 1 whErein:

said coupling circuit means is an amplifier for receiving and amplifying said input actuating signal, and the bias power supply for said amplifier is at the terminals on opposite sides of said one voltage reference diode.

4. A switch according to claim 3 wherein:

a. A resistance is connected between the gate of said first electronic switch and the other main terminal of the first electronic switch;

b. a bridge rectifier is connected, at its opposite uni-directional nodes, between the gate of said first electronic switch and main terminal of said first electronic switch; and

c. said second electronic switch is connected between the opposite uni-directional nodes of said bridge rectifier.

5. An electronic timing switch for controlling the power applied to a load which is connected to said switch and to a source of electrical power, in response to an input actuating signal, said switch comprising:

a. a triac, the main terminals of which are the switch terminals, for switching the current in said load;

b. a bridge rectifier connected at its opposite bi-directional nodes between the gate of said triac and a main terminal of the triac for switching the gate current of the triac;

c. an SCR having its main terminals connected to the opposite uni-directional nodes of said bridge rectifier in a di-rection to, at times, permit substantial current flow between said uni-directional nodes;

d. an amplifier means having its output connected to the gate of said SR for firing said SCR in response to the presence of said input actuating signal at the input of said amplifier;

e. a timing circuit means connected across said SCR and comprising a plurality of series connected, similarly polarized voltage reference diodes parallel connected to a capacitance for fixing the voltage to which the capacitance may charge, and having a resistance series connected to said parallel connected diodes and capacitance, the total zener voltage of said diodes being less than the peak, instantaneous voltage across the SCR, the biasing supply terminals of said amplifier being connected across one of said voltage reference diodes for supplying power to said amplifier.

6. A switch according to claim 5 wherein:

a resistance is connected between the gate of said triac and the other main terminal of the triac and has a value substantially less than the off-state impedance of the gate of the triac.

7. A switch according to claim 6 wherein:

a pair of zener diodes are used and the zener voltage of said one diode is equal to the desired amplifier power supply voltage and the zener voltage of the other diode is substantially greater.

8. A switch according to claim 7 wherein:

The product of the value of said resistance in ohms and said capacitance in farads is of the same order of magnitude as the on and the off periods of said switch.

9. A switch according to claim 8 wherein:

said resistance is approximately 22 X 103 ohms, said one zener voltage is approximately 7.5 volts and the other zener voltage is approximately 37 volts.

10. A switch according to claim 5 wherein:

a mechanical switch, for manual switching, is connected parallel to said triac.

11. A switch according to claim 5 wherein a sound transducer is connected to the input of said amplifier means.

12. A switch according to claim 5 wherein:

a resistance is connected between the gate of said triac and the other main terminal of the triac and has a value substantially less than the off-state impedance of the gate of the triac.

13. A switch according to claim 6 wherein:

a pair of zener diodes are used and the zener voltage of said one diode is equal to the desired amplifier power supply voltage and the zener voltage of the other diode is substantially greater.

14. A burglar deterrent comprising: