EP0295456B1 - Alarm interrupting means, in particular for alarm clocks or time scheduling clocks - Google Patents

Abstract

The means enables a signal transmitted by the clock to be interrupted or else finally turned off by the user approaching the clock, or else moving only a part of his body, for example his hand towards it. The clock is preferably equipped with a transmitter 2, 2' emitting infrared radiation or ultrasonic waves and a corresponding receiver 3, 3' which detects infrared radiation or the ultrasonic waves reflected by the moved body part 1. The temporal change in intensity is determined in a signal-conditioning circuit 4, 5 and 6 and compared in a threshold switching stage 7 to a prescribable value upon the overshooting of which the alarm signal A is turned off. <IMAGE>

Description

The invention relates to an alarm shutdown device, in particular for alarm clocks or appointment clocks.

The alarm devices emitting an acoustic alarm signal contained in alarm clocks or appointment clocks are usually switched off by the user of the clock by means of a movable switching element that can be actuated by hand, for example a button or a rocker. For example, an alarm clock is known from DE-GM 78 27 708, in which a switching rocker extending almost over its entire width is attached to the top of the housing.

From DE-GM 83 12 662 an alarm clock is already known, the switching device for interrupting the alarm signal no longer contains a movable switching element, but only has two so-called sensors, when they are touched simultaneously, for example with a fingertip, the alarm signal is interrupted. The touch sensors can be simple metal wires or _ as described in DE-GM 83 12 662 _ only consist of a conductive lacquer layer applied to the housing. However, the user of the clock must also at least touch the alarm clock here in order to achieve the desired interruption of the alarm signal.

In the battery-operated alarm device described in DE-PS 34 04 252, the user of the watch can interrupt the alarm signal by means of an acoustic signal formed by the human voice or can finally switch it off, so that touching the alarm device is no longer required. The acoustic signal formed by the human voice is received in this alarm device by a microphone, a filter and amplifier unit and a rectifier having a reception and signal shaping circuit, the output of which is connected to the input of a monostable multivibrator, which, when the signal level is high enough astable state passes. With this transition, the signal changes at an input of an integrated clock circuit, whereupon this interrupts the transmission of the driver signal for an alarm signal converter. To save electricity, both the microphone and the filter and amplifier unit are therefore connected to their voltage supply only after the start of the alarm signal.

A disadvantage of this alarm device is that despite an expansion of the circuit by a high and low pass, whereby practically only frequencies around 1000 Hz (range of the fundamental tone of the human voice) are amplified, external noises caused by various sound sources lead to the alarm signal being switched off before the sleeping person is woken up.

Another disadvantage of this alarm device is that the acoustic signal emitted by the user of the watch can inadvertently wake up other people present.

From DE-OS 30 40 751 a contactless switch is known which works with an IR transmitter and receiver. However, the known transmission / reception device designed as a reflection light barrier cannot be used as an alarm shutdown device for a watch, because numerous objects such as, in particular, in the area of action of such an alarm shutdown device a pillow or the sleeper itself is present, which can lead to self-shutdown. When using this known contactless switch for an alarm clock or appointment clock, either all objects with a noticeable reflection of infrared rays would have to be removed from the range of action of the transmitting and receiving device or the clock would have to be set up in an appropriate place.

It is therefore an object of the invention to provide a non-manual alarm switch-off device for an alarm clock or appointment clock that works in a fail-safe manner while maintaining a low power consumption, that is fully usable even without a special selection of the installation location of the clock and in the further, People present in the room cannot be unintentionally awakened or disturbed by the measures necessary to switch off the alarm signal.

The object of the invention is achieved for an alarm clock according to the preamble of claim 1 by the features contained in the characterizing part.

Thus, the receiving and waveform circuit of the alarm shutdown device works as an infrared motion detector, which in an advantageous embodiment can detect, for example, the heat emanating from the hand of the user via a receiver or can be designed as a transceiver in which a transmitter is transmitting at a specific frequency Transmitter is provided, the infrared radiation of which is reflected, for example, by the hand of the user. If a transmitter is provided, such an alarm shutdown device works as a reflection motion detector. So the alarm shutdown device only responds to a movement within the reception area and indicates next to one Filter amplifier, a threshold switching stage also a rectifier and differentiating stage.

In the alarm shutdown device according to the invention, an ultrasonic transmitter and receiver can also be used instead of an infrared receiver or instead of an infrared receiver together with the transmitter. In addition to the change in intensity of the reflected ultrasound waves, a frequency shift between the transmitted and received signals caused by the Doppler effect can also be evaluated in an ultrasound receiver, since in contrast to the infrared radiation area, the frequency shift due to moving body parts is no longer only negligibly small in the ultrasound range.

The differentiating stage is preferably followed by a signal delay stage on the output side or in parallel. The signal delay stage has the effect that the person to be woken up does not interrupt its further transmission when the wake-up signal sounds, by uncontrolled movements which are still half-asleep. The delay period is therefore dimensioned such that a wake-up signal of such a duration is emitted that the person to be woken up is put into an awake state with sufficient certainty. The alarm shutdown device thus only becomes fully operational after a certain delay period.

Due to the fact that the signal delay stage is arranged separately from the filter amplifier, the dynamic modulation range of the filter amplifier can be increased by an advantageous dimensioning of the rectifier and differentiating stage so that an additional, automatic gain control is no longer necessary. Despite that of objects at rest Originating, time-constant reflection signal is, as appropriate tests have shown, by this further development of the invention the filter amplifier is fully controlled only in the very rarest of cases by stationary objects. The arrangement of a signal delay device within the filter amplifier, on the other hand, would require complex gain control.

Further advantageous embodiments of the alarm shutdown device according to the invention can be found in the subclaims.

• Fig. 1 ein Ausführungsbeispiel einer Alarmabschalteinrichtung nach der Erfindung anhand eines Blockschaltbildes;
• Fig. 2 ein Impulsdiagramm, das die Wirkungsweise der Alarmabschalteinrichtung aus Fig. 1 erläutert;
• Fig. 3 Ausführungsbeispiele einer Gleichrichter-/Differenzierstufe, einer Signalverzögerungsstufe und einer Schwellwertschaltstufe nach Fig. 1;
• Fig. 4 Ausführungsbeispiele einer Schaltstufe, einer EIN/AUS-Steuerstufe und eines Ausschaltgliedes aus Fig. 1;
• Fig. 5 Ausführungsbeispiele einer Sende- und Empfangsstufe aus Fig. 1,
• Fig. 6 ein Gehäuseausschnitt einer Uhr, die mit einer Alarmabschalteinrichtung nach der Erfindung ausgestattet ist,
• Fig. 7 ein Ausführungsbeispiel eines Ultraschallempfängers zur Verwendung in der erfindungsgemäßen Alarmabschalteinrichtung,
• Fig. 8 ein Ausführungsbeispiel eines Ultraschallsenders, der mit dem Ultraschallempfänger nach Fig. 7 zusammenwirkt,
• Fig. 9 ein erstes Ausführungsbeispiel einer Baugruppe, die gleichzeitig als Ultraschallempfänger und -sender arbeitet und
• Fig. 10 ein zweites Ausführungsbeispiel einer Baugruppe, die gleichzeitig als Ultraschallempfänger und -sender arbeitet.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Show it:

• Figure 1 shows an embodiment of an alarm shutdown device according to the invention using a block diagram.
• Fig. 2 is a timing diagram explaining the operation of the alarm shutdown device of Fig. 1;
• 3 shows exemplary embodiments of a rectifier / differentiator stage, a signal delay stage and a threshold switching stage according to FIG. 1;
• Fig. 4 embodiments of a switching stage, an ON / OFF control stage and an opening element from Fig. 1;
• 5 shows exemplary embodiments of a transmission and reception stage from FIG. 1,
• 6 shows a section of the housing of a watch which is equipped with an alarm shutdown device according to the invention,
• 7 shows an exemplary embodiment of an ultrasound receiver for use in the alarm shutdown device according to the invention,
• 8 shows an exemplary embodiment of an ultrasound transmitter which interacts with the ultrasound receiver according to FIG. 7,
• Fig. 9 shows a first embodiment of an assembly that works simultaneously as an ultrasonic receiver and transmitter and
• Fig. 10 shows a second embodiment of an assembly that works simultaneously as an ultrasonic receiver and transmitter.

Fig. 1 shows a block diagram of an appointment or alarm clock, which is equipped with an alarm shutdown device according to the invention. The modules shown in Fig. 1 partly have the same function as in the alarm shutdown device known from DE-PS 34 04 252. However, the alarm shutdown device according to the invention works as a motion detector and not as a speech-sensitive switching device. The mode of operation of the alarm shutdown device is described below in connection with the pulse diagram shown in FIG. 2.

Reference number 1 denotes a non-stationary reflector for infrared rays emitted by a transmitter 2, for example the moving hand of an awakened person. The full battery voltage is present at connection U. From the connection U, the battery voltage reaches a clockwork 14, a signal generator 12, a lamp driver 9 and a monoflop 8. Although the battery voltage is present on all assemblies 8, 9, 12, 14, only the clockwork 14 is in the active state and therefore requires battery power. When a manually operated switch 18 is closed, an automatic wake-up device contained in the circuit of the clockwork 14 is in the ready position. If the time held in the clockwork 14 reaches the set wake-up time, a second switch (not shown) is closed in this, which is in series with the switch 18. When the second switch is closed (time t 1 in FIG. 2), an integrated circuit, likewise not shown, in the clockwork 14 is activated, which supplies the signal generator 12 with a wake-up signal A. The signal generator 12 converts the wake-up signal A into an acoustic signal A 'which is intended to wake the sleeping person. The wake-up signal A or acoustic signal A 'consists of a short pulse train of individual pulses with a frequency in the audible range. After a short pause, the first pulse train is followed by a second pulse train. The pulse trains are emitted until the awakened person triggers the alarm shutdown device or the integrated circuit interrupts the wake-up signal by self-shutdown, for example after 128 seconds.

The wake-up signal A is fed to activate the alarm shutdown device via a zener diode 19 and a diode 20 of an ON / OFF control stage 13, the circuit diagram of which is shown in FIG. 4. In the control stage 13 by means of a further Zener diode 42 and a charging capacitor 41, an ON signal is formed, which has the charging curve of the capacitor 41 corresponding to "t" at time t 1 and reaches its maximum voltage value until time t 2. The voltage value reached at time t2 causes transistor 64 (see FIG. 4) to switch on (output signal C). The transistor 38, which belongs to a switch-off element 11, is still blocked and, as described below, is only activated from the later point in time t4.

The output signal C, which is fed via a resistor 43 to a series transistor 44 of a switching stage 15, causes the series transistor 44 to switch on the battery voltage U at time t2. Consequently, the modules 2, 3, 4, 5, 6 and 7 are only supplied with the signal D (switched-through battery voltage U) from the time t2. From this point on, the transmitter 2 therefore emits transmission pulses which are reflected, for example, by the pillow or the sleeping person themselves and are detected by a receiver 3 (output signal E). The detected signal E passes via a filter amplifier 4, whose pass band is matched to the transmission pulse frequency, as signal M to a rectifier and differentiator stage 5. In its rectifier stage, a DC voltage which also increases in intensity is formed from the AC transmission signal.

The rectifier and differentiating stage 5 is shown in FIG. 3 together with a signal delay stage 6 and a threshold switching stage 7. The signal M passes through a capacitor 27 to two diodes 28, 29. The two diodes 28, 29 work together with the capacitors 27, 31 as a voltage doubler circuit and rectify the signal M. The rectified signal M charges a capacitor 31 which can be discharged again via a parallel resistor 30. The rectifier stage is followed by a differentiation stage, consisting of the capacitor 32 and the resistor 33. The differentiating stage causes the alarm shutdown device not to respond to the intensity of the received signal E, but to its change over time. That is, the signal P at the output of the rectifier and differentiator stage 5 is a function of the speed of movement of the reflector 1, and the limit frequency of the differentiator 32, 33 determines the minimum approach speed of the reflector 1 towards the clock in which the transmitting and receiving device are housed.

By tuning the components of the filter amplifier 4 and the rectifier and differentiator stage 5 according to the invention, it is possible to achieve an expansion of the dynamic range in the amplification of the signal E and the signal P derived therefrom. The large dynamic modulation range means that a static reflector that may be present at the amplifier input only rarely produces an input voltage that drives the amplifier to saturation. An automatic gain control is therefore not necessary.

• U_e: Eingangsimpulshöhe des Filterverstärkers 4 (Signal E)
• U_a: Ausgangsimpulshöhe des Filterverstärkers 4 (Signal M)
• T : Ausgangsimpulsbreite des Signals M
• T_a: Aufladezeitkonstante des Kondensators 31 (Fig.3)
• T_e: Entladezeitkonstante des Kondensators 31
• T_o: Impulsperiode des Senders 2
• N : Anzahl der Sendeimpulse des Senders 2
• U_c: Gleichrichtspannung am Kondensator 31.

The following variables are introduced below to explain the reason for the advantageous expansion of the modulation range:

• U _e : input pulse height of filter amplifier 4 (signal E)
• U _a : output pulse height of filter amplifier 4 (signal M)
• T: output pulse width of the signal M
• T _a : charging time constant of the capacitor 31 (FIG. 3)
• T _e : discharge time constant of the capacitor 31
• T _o : pulse period of transmitter 2
• N: Number of transmitter pulses 2
• U _c : rectification voltage across capacitor 31.

Für den Fall T_a, T_e ≧ T_o ergibt sich im stationären Zustand der arithmetische Mittelwert < U_c > der Gleichrichtspannung U_c zu:
$${\text{< U}}_{\text{c}}{\text{> = U}}_{\text{a}}{\text{T/T}}_{\text{o}}$$

Daraus ergibt sich, daß < U_c > auch bei bereits eingetretener Begrenzung der Ausgangsimpulshöhe U_a (Sättigung des Filterverstärkers 4) noch zunehmen kann und zwar aufgrund einer Zunahme der Ausgangsimpulsbreite T. Eine derartige Zunahme der Ausgangsimpulsbreite T liegt hier vor, da der Filterverstärker 4 eine differenzierende Wirkung aufweist und daher die Ausgangsimpulsbreite mit zunehmender Eingangsimpulshöhe zunimmt. Diese Zunahme tritt auch dann noch ein, wenn der Filterverstärker 4 bereits voll ausgesteuert ist und daher die Ausgangsimpulshöhe U_a nicht mehr zunehmen kann.The time-dependent instantaneous value U _c (t) follows the function:
$${\text{U}}_{\text{c}}{\text{(t) = U}}_{\text{a}}{\text{× (1 \_ exp TN (t) / T}}_{\text{a}}\text{)}$$

In case T _a, T _s ≧ T _o the arithmetic mean <U _c> of the rectified voltage U arises in the steady state _c:
$${\text{<U}}_{\text{c}}{\text{> = U}}_{\text{a}}{\text{T / T}}_{\text{O}}$$

It follows from this that <U _c > can also increase even if the output pulse height U _a (saturation of the filter amplifier 4) has already been limited, specifically because of an increase in the output pulse width T. Such an increase in the output pulse width T is present here because the filter amplifier 4 has a differentiating effect and therefore the output pulse width increases with increasing input pulse height. This increase also occurs when the filter amplifier 4 is already fully driven and therefore the output pulse height U _a can no longer increase.

The pulse of the signal P derived from the signal E could be used without a time delay to interrupt the transmission of the acoustic wake-up signal A ', which is already emitted from time t1. According to the invention, however, a signal delay is provided for the signal P for two reasons, which causes pulses of the signal P to switch off the wake-up signal A only after a certain dead time.

On the one hand, a person who is asleep can move due to the wake-up signal during the transition from the sleep state to the awake state, e.g. turn around in bed. Such a movement could result in the alarm shutdown device being switched off before the person has reached a sufficient waking state. As a result, no further wake-up sounds would be given and the person to be woken up would fall back to sleep.

On the other hand, it must be taken into account that the capacitor 31 (cf. FIG. 3) is uncharged when the battery voltage D is switched on at the time t1. The charging current surge occurring at the start of charging would be sufficient to generate a pulse on the differentiating element 32, 33, which has the same effect as the signal P, and which actuates the alarm shutdown device and interrupts the output of the wake-up signal A. Therefore, the signal delay stage 6 is provided, which provides a sufficient dead time so that the capacitor 31 can be charged on the one hand and on the other hand a minimum number of wake-up pulse trains are emitted, which lead to a safe wake-up of the sleeping person.

In Fig. 1, the signal delay stage 6 is exemplarily connected in series in the signal processing chain from the modules 3, 4, 5, 7, 8. 2, the signal delay stage 6 is only switched through at time t3 (signal F). The delay or dead time thus results from t3-t2. Likewise, the threshold switching stage 7 downstream of the signal delay stage 6 can only further process interrupt signals for the wake-up signal A arriving at time t3. The temporally active operating range of the alarm shutdown device thus arises according to signal G from time t3.

If the person now woken up by the wake-up signal A wants to interrupt the delivery of further wake-up signals A, they only have to briefly move the hand acting as the reflector 1 into the range of action of the transmission pulses emitted by the transmitter 2. An exact grasping of the clock and actuation of the switch 18 is not necessary since the radiation field of the transmission impulses extends to the person lying in bed. With the movement of the reflector 1, a short pulse H arises at the point in time t4 at the output of the threshold value switching stage 7. The threshold value switching stage 7 is necessary so that a specific received signal value can be determined from which the wake-up signal A is interrupted. The output pulse H of the threshold switching stage 7 arrives at a monoflop 8, which toggles into its unstable state at the time t4. With the tilting of the monoflop 8, the delivery of the wake-up signal A is interrupted, since the output signal I of the monoflop 8, in addition to the assemblies 9 and 11, is also supplied to the integrated circuit in the clockwork 14, which emits the drive pulses for generating the acoustic signal A 'in the signal generator 12 interrupts. A lamp 10, which illuminates the dial of the clock, is switched on via the lamp driver 9 (output signal K). The lamp 10 is switched on simultaneously at the time t4 with the tilting of the monoflop 8. When the monoflop 8 tilts back into its stable state at the time t6, the lamp 10 is switched off again. The lamp burning time is thus determined according to the unstable state duration of the monoflop 10, which ranges from t4 to t6.

As shown in FIGS. 1 and 4, the signal I is also supplied to the switch-off element 11. The switch-off element 11 consists of the transistor 38, a base resistor 40 and a collector resistor 39. The transistor 38 connected in the emitter circuit lies in the base-emitter circuit of the transistor 64 of the ON / OFF control stage 13. The rising edge of signal I at time t4 causes transistor 38 to turn on. When transistor 38 turns on, a capacitor 41 discharges through collector resistor 39. At time t5, the voltage value of signal B has dropped to a low value, so that transistor 64 and consequently transistor 44 simultaneously block. The battery voltage D is thus separated from the modules 2, 3, 4, 5, 6, 7 at the time t5. That is, the switching on of the switching stage 15 is effected via the signal B (time t2) and the switching off via the signal L, which is derived from the signal I, at the time t5. The alarm shutdown device is thus in the idle state and is put into operation again in the manner described above by switching the battery voltage D when the switch 18 is closed, the full functionality only being achieved after the delay or dead time t3-t2. Until the switch 18 is opened, a new wake-up process (snooze) takes place after a few minutes by the integrated circuit in the clockwork 14 by emitting the wake-up signal A. In a known manner, the alarm shutdown device is only finally switched off when the switch 18 is opened.

3 shows, in addition to the rectifier and differentiating stage 5, an exemplary embodiment for the signal delay stage 6 and the threshold switching stage 7, the most important component of which is a comparator 21 and 22, respectively. The operating voltage D is fed to the comparators 21, 22. The supply voltage N applied to the filter amplifier 4 is smoothed by the series resistor 17 and a capacitor (not shown) contained in the filter amplifier 4.

The operation of the signal delay stage 6 is that the comparator 21 at the plus input the voltage of the Resistors 25, 23 formed voltage divider is supplied. The minus input of the comparator 21 is connected to a divider which is formed from a series connection of a capacitor 26 and a resistor 24. The capacitor 26 is connected to the voltage N and the resistor 24 to ground. The negative input is at the center connection of capacitor 26 and resistor 24. When voltage N is applied at time t2, the negative input is more positive than the positive input. The output of the comparator 21 is thus at zero potential, which is why undesired pulses of the signal M are short-circuited to ground via the capacitor 32. After the delay time or dead time t3-t2, the capacitor 26 has been charged via the resistor 24 to such an extent that the negative input is now more negative than the positive input. The comparator output then switches off and output Q becomes high-impedance or ineffective because it is an operational amplifier (LM 393) with an OPEN collector output. The time-determining element, which determines the delay time or dead time, represents the series connection of the capacitor 26 and the resistor 24. The changeover point also depends on the level of the voltage value set on the resistor 23. In contrast to FIG. 1, according to which the signal delay stage 6 lies in series in the transmission chain, the delay stage 6 according to FIG. 3 is designed as lying parallel to the rectifier and differentiator stage 5, which is why it is switched on during the delay time and is subsequently inactive.

The threshold switching stage 7 consists of the resistors 34 and 35 forming a voltage divider, the tapping point of which is connected to the minus input of the comparator 22. The plus input of the comparator 22 is connected to the output of the differentiating element 32, 33 and the output Q of the comparator 21. On the output side, the comparator 22 has a diode 37 which is connected to the Input of the monoflop 8 is connected, and a resistor 36 which is connected to the battery voltage D. If the voltage jump supplied via the capacitor 32 exceeds the reference voltage formed by the voltage divider 34, 35, the comparator output switches from zero to the battery voltage D. This output pulse at the comparator 22 causes the monoflop 8 to tilt at time t4 via the diode 37.

5 shows an exemplary embodiment of the transmitter 2 and the receiver 3. The voltage D or the input signal O is supplied to the transmitter 2 via a resistor 16. Together with a capacitor 45, the resistor 16 decouples the transmitter 2 and the receiver 3 so that there are no transmission pulse-shaped operating voltage fluctuations in the receiver 3. Furthermore, the transmitter 2 consists of two complementary transistors 50, 51, which together with the resistors 46, 48, 49, 52 and a capacitor 47 form an astable multivibrator. The pulse repetition frequency is determined by the capacitor 47 and the resistor 46. The pulse width results from the dimensioning of capacitor 47 and resistor 48. An infrared diode 55 is used as the transmitting element, the anode of which lies on the connecting line between a resistor 54 and a charging capacitor 56. The cathode of the diode is connected to the collector of transistor 51 via a resistor 53. In the blocked state of transistor 51, capacitor 56 is charged via resistor 54 and discharged via diode 55 when transistor 51 turns on. Resistor 53 limits the diode current. Pulse operation relieves the battery because the battery capacity is limited. The pulse repetition frequency is preferably 500 Hz.

The infrared rays emitted by the diode 55 are reflected on the reflector 1 and reach the receiving element, one in infrared-sensitive diode 56, which is connected to the battery voltage N with the cathode. Together with a resistor 57, the diode 56 forms a voltage divider, to the connection of which a capacitor 58 is connected, which supplies the transmission pulses received by the diode and converted into current pulses to the filter amplifier 4.

6 shows a side view of a partially broken watch case 60 with a dial 61. The receiving and transmitting elements 55, 56 are preferably formed at a distance from one another on the upper edge of the front of the watch case 60. In the wall of the housing 60, depending on the number of transmission and reception elements 55, 56, inlet and outlet openings 59 are provided for the transmission and reception signals. The main radiation direction X (or reception direction) defined by the radiation characteristic of the receiving and transmitting element can be inclined upwards or downwards relative to the horizontal Y, depending on the application. The main radiation direction is preferably inclined upward by an angle α of 20 ° to 25 °.

The choice of a main radiation direction which is not perpendicular to the dial 61 represents, in addition to the working point of the threshold switching stage 7 determined by the dimensioning of the capacitor 31 and the resistor 30, a further possibility of adapting the responsiveness of the alarm shutdown device to practical requirements. The inclination of the main radiation X upwards by 20 ° to 25 ° serves in particular to suppress static reflectors, such as a lamp, books or the like, as far as possible, which can be located directly in front of the clock. Of course, the responsiveness of the alarm shutdown device can also be also adapt to the practical circumstances by dimensioning the filter amplifier 4.

Although the alarm shutdown device according to the invention has so far only been described using exemplary embodiments with an infrared transmitter and receiver which evaluates the change in intensity of the received signal caused by the movement of the reflector 1, an infrared radiation emitting transmitter can be dispensed with if the receiving diode 55 is provided by a passive infrared detector is replaced, which has such a sensitivity that it can detect the heat radiation emitted by the user of the watch itself.

Furthermore, the invention is not limited to exemplary embodiments that work with a filter amplifier. Rather, frequency discriminators or sample and hold circuits can also be formed in the signal chain from the receiver 3 to the monoflop 8. In addition, the invention can be designed so that it also responds to moving the reflector away from the clock in addition to approximations.

Fig. 7 shows an embodiment of an alarm shutdown device which has an ultrasound receiver 3 'instead of an infrared-sensitive receiver, which is coupled via a capacitor 58 to the filter amplifier 4. The corresponding part of the description of FIGS. 1 to 6 applies equally to the mode of operation of the ultrasound receiver 3 ', so that the mode of operation of these modules is no longer discussed below. An essential part of the ultrasonic receiver 3 'are two npn transistors 63, 64, the operating points of which are set with the aid of resistors 65, 67, 68 and 98. An Ultra is used to record ultrasonic waves sound transducer 62, for example a piezoceramic transducer, which is connected in series with the resistor 65. The resistor 65 together with the resistor 98 defines the operating point for the transistor 63, while the ultrasonic transducer 62 in the base-emitter branch of the transistor 63 serves as a signal source for the filter amplifier. The signals emitted by an ultrasound transmitter are detected by the ultrasound converter 62 and converted into voltage changes, which are amplified as AC voltage signals and fed to the downstream transistor 64 via a capacitor 66. On the output side, the amplified signal is tapped at the collector of transistor 64 and processed further in the downstream modules in the manner described above.

Fig. 8 shows an embodiment of an ultrasonic transmitter 2 ', which emits pulses as an astable multivibrator preferably at a frequency between 30-40 KHz, which are detected by the receiver 3' shown in Fig. 7. The ultrasonic transducer 62 lies above a series resistor 77 in the collector branch of a transistor 71. In contrast to FIG. 7, the ultrasonic transducer 62 according to FIG. 8 now converts voltage changes at the collector of the transistor 71 into ultrasonic vibrations, which, as previously described, by the receiver 3 ' be converted back into voltage changes. An essential part of the ultrasonic transmitter 2 'are two npn transistors 70, 71, two capacitors 72, 73 serving as feedback elements in the generation of the vibrations. The resistors 69, 74, 75, 76 in turn serve to set the operating point of the two transistors 70 and 71.

FIG. 9 shows an exemplary embodiment in which, in deviation from FIGS. 7 and 8, the transmitter and receiver are in one assembly are summarized, that is, the assembly shown in Fig. 9 works simultaneously as a transmitter and receiver. The two transistors 80, 81 are connected here to form an emitter-coupled astable multivibrator, the two emitters being coupled by the ultrasound transducer 62, which rotates the phase by 180 ° when resonating. The resistor 87 serves to decouple the output signal from the oscillation pulses. The capacitor 78 together with the resistor 88 forms a sieve element in order to decouple the supply voltage from the oscillation pulses. Again, resistors 82, 84, 83 and 85 serve to set the operating point of transistors 80, 81, while the degree of feedback is set with the voltage divider consisting of resistors 86 and 87. Since the transistor 80 operates in the base circuit, the base is short-circuited to "zero" via the capacitor 79 for decoupling between the input and output signals.

If the sound waves emitted by the ultrasonic transducer 62 are reflected, they return to the latter and are then converted back into voltage pulses. That is, the sound waves generated overlap with the reflected sound waves, with the ultrasound transducer 62 simultaneously converting voltage values into emitted sound waves and, conversely, converting the reflected sound waves into voltage values. This is possible because the ultrasound transducer can work reversibly. Accordingly, the voltage values at the emitter of the transistor 81 are also superimposed, with only the change in the reflection of the ultrasound waves from a moving object, for example a hand, being evaluated in the downstream stages, as described above. If ultrasonic waves are simultaneously reflected from stationary and moving objects, the Doppler effect creates a beat with a frequency that depends on the speed of movement.

Fig. 10 shows a second embodiment of an assembly that works simultaneously as a receiver and transmitter. An essential component of the circuit according to FIG. 10 is an npn / pnp transistor pair 90, 91 in a complementary circuit. A capacitor 93 is provided as the feedback element. The ultrasonic transducer 62 is connected in series with a potentiometer 96 in the emitter branch of the transistor 91. The series circuit comprising the resistor 96 and the transducer 62, which, because of the capacitive effect of the transducer 62, only allows an AC voltage flow, is connected in parallel with an emitter resistor 97 to maintain the emitter current flow. The voltage level of the feedback pulses, which are fed to transistor 90 via capacitor 93, can be set by means of potentiometer 96. The resistors 89, 92, 94, 95 in turn serve for setting the operating point, the resistors 94, 95 (shown in dashed lines) can also be omitted in certain applications.

Claims (20)

1. An alarm shut-off device, in particular for an alarm clock or timer, with a clockwork containing an integrated circuit which, when the clock time matches the alarm time, delivers a wake-up signal to a signal generator preferably configured as an electroacoustic transducer, with a receiving and signal shaping network which includes a receiver, a filter amplifier, a rectifier circuitry and a threshold switching stage for receiving and further processing a shut-off signal issued by the user of the clock, and which is not connected to its voltage supply until after the wake-up signal is delivered following which it processes the shut-off signal such that its application to an input of the integrated circuit causes this circuit to interrupt the delivery of the wake-up signal, characterized in that the receiving and signal shaping network includes a receiver (3, 3′) sensitive in the infrared radiation range or in the ultrasonic range and further includes, in a rectifier and differentiator stage (5), a differentiator (32, 33) connected subsequent to the rectifier circuitry (27-31), the output signal (P) of which is determined by the variation with time of the infrared radiation or ultrasonic waves detected by the receiver (3, 3′).

2. An alarm shut-off device as claimed in claim 1, characterized in that it includes a transmitter (2, 2′) emitting infrared radiation or ultrasonic waves, the transmitter signals being reflected by the user of the clock and detected by the receiver (3, 3′).

3. An alarm shut-off device as claimed in claim 1 or claim 2, characterized in that between the output of the threshold switching stage (7) and the input of the integrated circuit a one-shot multivibrator (8) is connected the output of which is connected to the input of the integrated circuit and which is caused to assume its astable state when an output signal (H) occurs at the output of the threshold switching stage (7) which is connected to its input.

4. An alarm shut-off device as claimed in claim 3, characterized in that the rectifier and differentiator stage (5) includes two series-connected assemblies of which the assembly acting as a rectifier is comprised of a voltage-doubling circuit including two diodes (28, 29) and two capacitors (27, 31), while the assembly acting as a differentiator is comprised of a capacitor (32) and a resistor (33) connected in series.

5. An alarm shut-off device as claimed in claim 4, characterized in that the receiving and signal-shaping network includes a signal delay stage (6) which is arranged ahead of the threshold switching stage (7) and delays, following delivery of the wake-up signal (A), its output signal (Q) relative to its input signal (P) for such a length of time (t3-t2) that the acoustic signal generator (12) issues an alarm signal (A′) at least for a determinable time span (t3-t1).

6. An alarm shut-off device as claimed in claim 5, characterized in that the signal delay stage (6) is connected in parallel with the rectifier and differentiator stage (5) and includes an open-collector comparator (21) the output of which is connected to the output of the differentiator (32, 33) of the differentiator stage (5), and that the delay time (t3-t2) is determined by a capacitor (26) and a resistor (24) connected in series.

7. An alarm shut-off device as claimed in claim 6, characterized in that the threshold switching stage (7) includes a comparator (22) having applied to its first input a reference voltage, its second input being connected both to the output (P) of the differentiator (32, 33) of the rectifier and differentiator stage (5) and to the output (Q) of the comparator (21) of the signal delay stage (6).

8. An alarm shut-off device as claimed in claim 3, characterized in that the wake-up signal (A), in addition to being applied to the signal generator (12), is further applied to a first input (B) of an ON-OFF control stage (13) via a Zener diode (19) and a diode (20) connected in series, said control stage connecting, via a switching stage (15), both the receiving and signal shaping network (3, 4, 5, 6, 7) and the transmitter (2) to their respective supply voltages (D, O).

9. An alarm shut-off device as claimed in claim 8, characterized in that the ON-OFF control stage (13) Z produces an ON signal from signal (B) present at the output of the diode (20) by means of a Zener diode (42) and a charging capacitor (41) in parallel arrangement, said ON signal rendering an output transistor (64) conducting with a determinable time delay (t2-t1), said output transistor in turn causing a series transistor (44) arranged in the switching stage (15) to conduct.

10. An alarm shut-off device as claimed in claim 8, characterized in that the output signal (I) of the one-shot multivibrator is further applied through a turn-off element (11) to a second input (L) of the ON-OFF control stage (13) the output signal (C) of which disconnects the receiving and signal shaping network (3, 4, 5, 6, 7) and the transmitter (2) from their respective supply voltages (D, O) via the switching stage (15) after the one-shot multivibrator (8) has switched to its astable state.

11. An alarm shut-off device as claimed in claim 9 and claim 10, characterized in that the turn-off element (11) is comprised of a common-emitter transistor (38) arranged in the base-emitter circuit of the output transistor (64) of the ON-OFF control stage (13) and having the output signal (I) of the one-shot multivibrator (8) applied to its base.

12. An alarm shut-off device as claimed in claim 2, characterized in that the transmitter (2) includes an infrared diode (55) emitting infrared radiation in the pulse control mode, with the pulse recurrence frequency and the pulse duration being determined by the dimensional design of a capacitor (47) and a resistor (46 and 48, respectively) combining with two further resistors (49, 52) to form an astable multivibrator.

13. An alarm shut-off device as claimed in claim 12, characterized in that the pulse recurrence frequency of the transmitter (2) is preferably in the range of 500 Hz in infrared operation.

14. An alarm shut-off device as claimed in claim 2, characterized in that the receiver (3) includes an infrared-sensitive diode (56) which has its cathode connected to a voltage (N) derived from the battery voltage (U) and combines with a resistor (57) to form a voltage divider to the tap of which a capacitor (58) is connected supplying the signals received from the diode (56) to the filter amplifier (4).

15. An alarm shut-off device as claimed in claim 2, characterized in that the receiver (3, 3′) and the transmitter (2, 2′) are relatively spaced on the upper edge of the front side of the clock housing (60), and that the main transmitting or receiving direction X of the transmitter or receiver signal is inclined upwardly relative to the horizontal Y preferably at an angle of between 20° and 25°.

16. An alarm shut-off device as claimed in claim 3, characterized in that the output signal (I) of the one-shot multivibrator (8) is further applied to the input of a lamp driver (9) the output signal (K) of which continues to differ from zero value as long as the one-shot multivibrator (8) is in its astable state.

17. An alarm shut-off device as claimed in claim 2, characterized in that the receiver (3′) and the transmitter (2′) operate in the ultrasonic wave range and form a joint transmitting and receiving assembly including an astable multivibrator with two emitter-coupled transistors (80, 81), with the ultrasonic transducer (62) forming the feedback element for generating the oscillatory response.

18. An alarm shut-off device as claimed in claim 17, characterized in that the ultrasonic transducer (62) is connected, via a decoupling resistor (87) arranged in the emitter branch of the two transistors (80, 81), to the output of the transmitting and receiving assembly, with the decoupling resistor (87) being connected in series with an emitter resistor (86).

19. An alarm shut-off device as claimed in claim 2, characterized in that the receiver (3′) and the transmitter (2′) operate in the ultrasonic wave range and form a joint transmitting and receiving assembly including an astable multivibrator with two transistors (90, 91) in complementary connection, that the ultrasonic transducer (62) is connected, in series arrangement with a resistor (96), in the emitter branch of the transistor (91) at the output end, and that an emitter resistor (97) is connected in parallel with the serially connected ultrasonic transducer (62) and resistor (96).

20. An alarm shut-off device as claimed in claim 19, characterized in that the resistor (96) is a potentiometer.

Images