DK151737B - Monitor for activation of a sound source or other alarm - Google Patents

Description

DK 151737 B

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a sound system for activating a sound source or other alarm, such as a bell, which system comprises one or more non-contact sensors for detecting a person or object, the sensor or sensors having a monostable circuit adapted to activate the alarm by means of a contact means such as a relay, when the circuit receives signal from at least one of the sensors.

15 Such plants are used in many places. Examples include monitoring of store entrances, exhibitions, back doors, corridors and corridors, etc. The plants can thus tell if a customer enters a store, with a bell or other sound source 20 giving a signal. Of course, such plants can also be used as anti-theft devices.

Many kinds of touch-free sensors are known. Among the most widely used are photocells and sound sources 25 with either visible or invisible light, ultrasonic transmitters and receivers and various types of radar.

Common to these is that the sensor emits an electrical signal when, for example, a person enters the monitoring field.

30

All known plants of this kind have the common disadvantage that they are relatively expensive and complicated. Thus, the installation often requires additional equipment, for example in the form of power supplies, at 2 o'clock

DK 151737B

1 and the like.

Thus, U.S. Patent No. 3,587,094 discloses a state-of-the-art message system in which the 5 monostable circuit upon activation opens the power supply to a complicated built circuit for activating the alarm. · Thus, the circuit cannot be combined with existing circuits, since the power supply is switched off when the monostabi-10 le circuit falls back, so that other alarm systems cannot immediately activate the alarm.

The object of the invention is therefore to provide a simple and inexpensive system which can furthermore easily be combined with existing reporting systems such as a doorbell without the use of optional equipment.

This is achieved according to the invention in that the mono-stable circuit and thus the sensor through its supply lines are connected in series with the alarm, that upon contacting the alarm the contact means is arranged to connect the alarm supply circuit and thereby short-circuit the supply lines to the monostable circuit, and that the plant additionally has one or more energy storage means for maintaining the supply voltage to the monostable circuit during an alarm.

30 This circuit is simple as it can be built up by standard standard components. The monostable circuit ensures that the alarm is activated only for a predetermined period of time. This can easily be used to activate an existing doorbell, 3

DK 151737 B

1 so that it gives a short signal, for example when a customer enters an exhibition area.

According to the invention, it is achieved that the system can easily utilize the existing power plant's power supply. Namely, the power supply circuit is often the most expensive part of an electronic system, so in this way the system according to the invention can be made relatively cheap. At the same time, it will be easy to install the 10 system.

If the system as claimed in claim 2 is provided with a capacitor between the supply lines, an inexpensive, yet well-functioning anise signal is obtained, and a diode is inserted in the positive supply line for the circuit to allow the current to flow. run to the capacitor anode, the capacitor is not discharged "backwards" through the contacts when the alarm is activated.

20

If the system is designed with a rectifier means as claimed in claim 3, it is achieved that the system can be used both with alternating and DC powered reporting systems.

25

It is also appropriate if the system has a manual switch. This can optionally be placed as a doorbell at a rear entrance or the like.

30 Finally, it is appropriate if the entire system is directly arranged for parallel connection with an existing reporting system, thereby achieving the simplest possible mounting.

DK 151737 B

The invention will now be described in more detail with reference to the drawing, in which: FIG. 1 is a schematic diagram of an inventive clock system 5 connected to an existing clock system, and FIG. 2 is a flow chart of one embodiment of a melter system according to the invention.

10

FIG. 1 shows a message system with an alarm 4, which may, for example, be a bell, a gong-gong or a siren. The reporting system has a power supply 1 which can either be a DC power source (for example 15 batteries) or a transformer connected to the mains.

In addition, the alarm system has a switch 3 which can connect the connection from the power supply 1 through the 20 wire 2 to the 4 o'clock and onwards through the wire 5 back to the power supply 1. If the switch 3 is activated, the alarm will sound.

Parallel to the switch is shown a plant 6 according to the invention. The system has at least one sensor for detecting a person or object 7.

All kinds of sensors can be used.

Among other things, photoelectric, apparatus or - (ultra) sound detectors, electromagnetic detectors 30 or heat sensitive detectors.

In FIG. 2, an embodiment of a plant according to the invention is shown in principle flow diagram.

DK 151737B

5 1 By means of the wires 2 ', 5 the supply current is passed through the clock at 4 o'clock to the system. This current is so small that 4 o'clock is not activated. Therefore, through the diode bridge 13 and diode 15, the capacitor 16 is charged.

The voltage across this capacitor is used to power the sensor 20 and a monostable circuit 19, the sensor input of which is connected to the sensor 20, which may be of any of the above mentioned species.

The output of the monostable circuit is connected to a relay coil 8. However, this can easily be replaced by another contact means, such as a transistor or another conductor contact.

When the sensor 20 detects a person 7, the following occurs: The sensor 20 sends an electrical impulse to the monostable circuit 19 which, for a predetermined period of time, activates the relay 8, which in turn connects wires 2 'and 5 to each other to activate the alarm.

20 Here, the supply lines 9 and 10 are short-circuited, but due to the diode 15, the capacitor 16 will retain its charge so that the monostable circuit 19 can be powered. After the predetermined period, the monostable circuit 19 falls back to the ground state, after which the relay drops, so the capacitor 16 is recharged.

It will be clear to one skilled in the art that capacitor 16 must have a suitable capacity relative to the pulse time so that the voltage across it does not change substantially. It will also be clear that the circuit can be designed integrally or with thick film technique.

DK 151737 B

e 1 The number of sensors can be varied as required, and different sensors can be used simultaneously in combination. This will ensure a facility that detects persons or objects with very high security.

5 10 15 20 25 30

Claims (3)

An alarm system for activating an alarm such as a bell, said system comprising one or more non-contact sensors for detecting a person or object, the sensor (20) or the sensors having a monostable circuit (19) arranged to activating the alarm (4) by means of a contact means (8) such as a relay when the circuit (19) receives a signal from at least one of the sensors (20), characterized in that the monostable circuit (19) and thus the sensor (20) through its 15 supply lines (9, 10, 17, 18) is connected in series with the alarm (4), that the actuator (8) is activated by activating the alarm (4) to close the supply circuits of the alarm and thereby short-circuit the supply lines ( 9, 10) to the monostable 20 circuit (19), and that the system further has one or more energy storage means (16) for maintaining the supply voltage to the monostable circuit (19) during the sounding of the alarm. An alarm system according to claim 1, characterized in that the energy storage means consist of a capacitor (16) connected between the supply lines (17, 18), in which a positive diode is inserted in the positive supply line (17) for the circuit (19). (15) in such an orientation that current is allowed to flow to the anode of the capacitor (16). An alarm system according to claims 1-2, wherein the alarm is operated with alternating current, characterized in that a rectifier means (13) such as a diode bridge is inserted between the alarm (4) and the monostable circuit (19). 5 10 15 20 25 30