DE3148243A1 - Method for driving a digital display of traffic lights and arrangement for carrying out the method - Google Patents

Abstract

In a method for driving a digital display of traffic lights, the light signal of the red lamp is received and used to resolve two counting operations, which alternate with the same clock frequency in opposite directions starting from the initial state zero in the forward direction or, starting from the final state reached during the preceding red light phase, in the reverse direction. The intermediate states of the reverse counting operation are continuously displayed on the digital display. The reverse counting operation is set to the initial state zero upon extinction of the red lamp at the latest, and the digital display is extinguished, while the forward counting operation is terminated upon extinction of the red lamp and the final state achieved is stored during the following green light phase. Furthermore, in order to increase traffic safety the light signal of the amber lamp is received and used to reset the instantaneously running counting down operation to the initial state zero and to extinguish the digital display.

Description

Description

The invention relates to a method for controlling a numeric display a traffic light and a traffic light with a circuit arrangement for implementation of the procedure.

A traffic light with a numeric display showing the remaining time of the Red light phae, preferably running backwards in seconds, gives you Road users the additional information how long they have to wait until the phase change occurs. In particular, the motorist can use the numeric display reliably decide whether it is still worth turning off the engine. So that can Saving fuel and reducing the pollution caused by noise and emissions will. Extensive studies have shown that waiting times over 20 seconds switching off the engine leads to a reduction in fuel consumption. Is there an automatic stop-start system available for the fuel supply is interrupted immediately when the engine is switched off, it is worth it from a waiting time of 5 seconds.

There is a traffic light of the type mentioned known (DE-OS 29 11 507), in which the counter controlling the digital display is switched synchronously with the traffic light is / wherein the indexing is timed so that the Duration of the display of one color in a number corresponding to the number of digits is divided by part-time> The control of the display must be in such a The event is carried out from the control center, via which the traffic light phases are also controlled will. Additional control lines must therefore be available for the numeric display be provided, which is associated with considerable additional effort. Also can existing traffic lights not without further ado with the numeric display can be retrofitted so that they can only be used with new or completely retrofitted traffic light systems is possible.

In contrast, the invention is based on the object of a method to control a digital display of a traffic light to develop that without Difficulties can also be applied to existing traffic lights and its practical implementation has only a relatively low level of circuitry and mechanical effort without interfering with the traffic safety endangering Traffic lights required.

To solve this problem, those specified in claim 1 are specified Process features proposed. Further advantageous refinements and developments of the method according to the invention emerge from subclaims 2 and 3.

According to the method according to the invention, the light signal of the red lamp received by a photo receiver and for triggering two in consecutive Red light phases alternating in opposite directions from the beginning stood zero in the forward direction or proceeding from the final position reached in the previous red light phase used counting processes running in reverse direction. The intermediate results of the The downward counting process, which preferably runs in steps of one second, is carried out on the The numerical display is continuously displayed. At the latest when the red lamp goes out the down counting process is reset to the starting position zero and the numeric display deleted while the counting up process ends when the red lamp goes out and the final score reached in the course of the following green phase until the next red light phase is saved.

For reasons of road safety, it should already be illuminated when it lights up the yellow phase, which shows the phase change from red to green, the numeric display be deleted so that the road user is aware of the phase change can focus on related actions. Therefore it is useful to also use the light signal to receive the amber lamp and to reset the currently reversing Counting process to the beginning was zero as well as to delete the current numerical display to use.

For the objective solution of the inventive problem, the will be claimed 4 suggested combination of features. In the further subclaims are also some advantageous refinements and developments of the invention stated in objective terms.

The circuit arrangement according to the invention can except for the photo receiver be indicated in the housing of the numeric display, for example for retrofitting purposes Designed separately from the traffic light housing or with new equipment with the traffic light housing can be connected.

As a photo receiver, a photodiode is preferably used, the one requires less space than the equally suitable photo resistors or photo transistors having.

The photo receiver is used on one side for shielding against extraneous light Open tube arranged in the traffic light housing, preferably on the lamp reflector can be attached with its opening pointing to the lamp in question. To a The tube should avoid the accumulation of condensation in the area of the photo receiver be arranged with its opening pointing vertically downwards.

The circuit arrangement according to the invention is particularly distinguished by this from the fact that they are without information from the control center and thus without a corresponding one Wiring to reliably determine the duration of the red light phase and its sequence able to display. The only electrical connection to the traffic lights is there in the power supply, which is adequately protected by overload protection can be, so that an influence or a disruption of the traffic light operation by the numeric display is excluded.

The invention is explained in more detail below with reference to the drawing. The single figure shows a basic circuit diagram of a preferred circuit arrangement for controlling a numeric display of a traffic light in a schematic manner shown.

The traffic light 10 consists of a housing 12 in which a red lamp 14 for blocking and a green lamp 16 for releasing the traffic flow and a yellow lamp 18 arranged between red lamp 14 and green lamp 16 for display purposes a phase change are arranged. The traffic light 10 is together with a larger number of further traffic lights with the interposition of local traffic light controls 19 from a control center 20 with mains power (network 22) and via an interval generator 24 is supplied with the switching signals necessary for the phase change.

The traffic light 10 is arranged above the red lamp 14 Housing 26 or housing part assigned a numeric display 28 on which the remaining time the red light phase is displayed running backwards in steps of one second. The numeric display 28 is controlled via an electronic circuit arrangement 30, the essential Components are shown in the figure. The one outlined with dash-dotted lines Part of the circuit arrangement 22 is accommodated in the housing 26 of the numeric display 28. The power supply connections - the numeric display 28 and the circuit arrangement 30 are with the interposition of an overload protection 32 with the power supply connected to VeYtèhrsampel 10.

The circuit arrangement 30 is located with two in the traffic light housing 12 in the area the red lamp 14 and the yellow lamp 18 arranged photo receivers 34,36 in connection.

As photo receivers 34, 36 are preferred because of their small footprint Photodiodes used. The photodiodes 34, 36 are each used to shield extraneous light arranged in a metal tube, not shown, open on one side, which is on respective reflector pointing vertically downwards to the red lamp 14 or yellow lamp 18 is attached for example by means of self-tapping screws, so that the photodiode is immediately is hit by the lamplight. With the vertical arrangement of the tube in the traffic light housing The purpose of 12 is to prevent condensation from collecting in the area of the photodiodes 34, 36 can.

The connections of the photodiodes 34,36 are detachable via not shown Plug or screw connections with the circuit arrangement located in the housing 26 30 in connection. There the electrical coming from the photo receivers 34,36 Signal first in a pulse shaper stage 38, 40 into a bounce-free square wave signal converted. The output signal of the pulse shaper 38 is once a clock generator 42 started via its input S when the red light lights up and when it goes out stopped. The clock generator 42 contains a quartz-stabilized oscillator, its High frequency reduced to an output frequency of 1 Hz via a frequency divider will. The 1 Hz clock signal of the clock generator 42 is applied to the clock input T two reversible BCD counter Z1 and Z2 placed with three decades each. The counting direction inputs - m of the two counters Z1 and Z2 become one in opposite directions via the outputs Q and Q Flip-flops 44 controlled, the via the negative edge of the output signal of the Pulse shaper 38 is triggered. This means that the outputs Q and Q swap after each Red light phase their logic states, so that the counting direction of the counters Z1 and Z2 is reversed for successive red light phases. In addition, the output Q is connected to the select input of the multiplexer selector 46 connected, the inputs El and E2 with the outputs A of the two counters Z1 and Z2 are connected and thus each the counter reading of the running backwards The counter switches through the decoder 48 to the numeric display 28.

The numerical display 28 shown in the drawing is around a three-digit 7-segment display, so that a BCD 7-segment decoder 48 for three Is to be used for decades. For reasons of insensitivity to interference, there are Display elements of the 7-segment display preferably made up of one or more light-emitting diodes, which contain a reflector to increase the luminosity.

As soon as the yellow light lights up during the red light phase, arrives A signal is sent to the reset input via the two AND gates 50, 52 and the OR gates 54, 56 R of the counter that is currently going backwards, which sets this counter to its initial status Resets zero so that the counting process begins at the beginning of the next red light phase starts again at 0. The counter that is currently running forward is also counted during the yellow light phase until the red lamp 14 goes out. In the subsequent In the green light phase, the final reading reached in this counter is saved and generated at the beginning of the next red light phase the output was shown on the numeric display 28 downcounting displayed.

Provided that the phase intervals are consecutive Traffic light periods kept constant by the interval generator 24 in the control center 20 will be, with the circuit arrangement described in the course of a single Traffic light period the necessary information for the duration of the red light phase determined so that the remaining time of the red light phase in the next traffic light period can be displayed on the numerical display 28. The duration of the red light phase is redefined at each traffic light period, so that any deviations occur at the next Period to be corrected. It can only be used in the one traffic light period, in which a phase change is taken over from the control center 20, to a There is no news: If the red light phase is extended, the time value appears 0 too early and the digital display goes out if the red light phase is still ongoing; at If the red light phase is shortened, the numeric display is replaced by the one that appears earlier Yellow light extinguished apparently too early. However, both cases lead no impairment of road safety, since the road user is at such changes are used, for example, when switching a traffic light system on and off.

In addition, this type of false indication with relatively simple Funds can be avoided.

As stated above, the only electrical one Connection between the traffic light 10 and the circuit arrangement 30 with numeric display 28 in the common power supply. The power supply can be used to a signal from the control center 20 to the traffic lights connected to it transmitted, which announces a change in the phase duration. This can 'for example done with the help of a simple modulator 58 in the control center 20, the one change signal emitted by the interval generator 24 in the form of a high-frequency signal modulated to the mains current. The high-frequency signal can then be in the circuit arrangement 30 received and in a demodulator 60 into a square wave signal can be converted in the circuit arrangement 30 for further evaluation. With this The two reset inputs R the counters Z1 and Z2 are activated, which means that both counters are reset to the initial value 0 will.

At the same time, the numeric display 28 goes out, so that during the critical Traffic light period during which the phase change is made, there is no display.

Claims (15)

Method for controlling a digital display of a traffic light and an arrangement for performing the method claims 1. Method for Control of a digital display (28) of a traffic light (10) with a red lamp (14) for blocking and a green lamp (16) for releasing the traffic flow and optionally a yellow lamp arranged between the red lamp and green lamp (18) to display a phase change, the numeric display (28) showing the remaining time the red light phase, preferably in steps of one second, running backwards, d a -d u r c h g e k e n n n z e i c h n e t that the light signal of the red lamp received and to trigger two with the same clock frequency alternately in opposite directions from the initial status Zero starting in the forward direction or from that in the previous red light phase The final count reached is used based on counting processes running backwards and that the intermediate values of the countdown process on the digit advertisement continuously displayed, with the downcounting at the latest when it goes out the red lamp or when the count reaches 0 is set to the initial reading zero and the numeric display is cleared and the counting up process when the Red lamp ended and the final result reached during the following green light phase is saved. 2. The method according to claim 1, d a d u r c h g e k e n n -z e i c h n e t that the light signal of the yellow lamp received and to reset the momentarily counting process running backwards to the starting position zero and to delete the numeric display is used. 3. The method according to claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that a central one arranged outside the traffic lights Control unit issued, announcing a change in the duration of the traffic light phases Signal received and to reset the counts -both counting processes to the Initial reading zero and is used to clear the current numeric display. 4. Traffic lights with a red lamp (14) for blocking and one Green lamp (16) for releasing the traffic flow and possibly one Yellow lamp (18) arranged between the red lamp and the green lamp to indicate a phase change and one the remaining duration of the red light phase, preferably running backwards in steps of one second indicating, electronically controlled numeric display (28), g e k e n n z e i c h -n e t d u r c h a photo receiver that can be acted upon by the light of the red lamp (14) (34) and one the electrical output signal of the photo receiver (34) processing Circuit arrangement (30) for controlling the numeric display (28), the circuit arrangement (30) a clock generator (42), two during successive red light phases alternately in opposite directions with the clock frequency of the clock generator (42) controllable Up / down counter (Zl, Z2) as well as a count output (A) of the momentary backward running counter to the numeric display (28) switching selector circuit (46) contains. 5. Traffic light according to claim 4, g e k e n n z e i c h -n e t d u r c h a further photoreceiver to which the light from the yellow lamp (18) is applied (36), with its electrical output signal the reset input (R) of the momentary counting down counter while resetting this counter to the beginning Zero can be applied. 6. Traffic light according to claim 4 or 5, d a d u r c h g e k e n n z e i c h n e t that the photo receiver (34,36) as a photo resistor, photo transistor or is preferably designed as a photodiode. 7. Traffic light according to one of claims 4 to 6, d a d u r c h g It is not noted that the photo receiver (34, 36) is used for shielding extraneous light is arranged within a tube open on one side, which is in the traffic light housing (12) preferably on the relevant lamp reflector with its opening to the relevant Lamp is attached pointing. 8. Traffic light according to claim 7, d a d u r c h g e -k e n n z e i c h n e t that the opening of the tube is essentially perpendicular to the bottom pointing in the traffic light housing (12) is arranged. 9. Traffic light according to claim 7 or 8, d a d u r c h g e k e n n z e i c h n e t that the connections which can be connected to the circuit arrangement (30) of the photo receiver (34,36) as a detachable screw-type screw arranged on the traffic light housing (12) or plug connections are formed. 10. Traffic light according to one of claims 4 to 9, d a d u r c h it is noted that the clock generator (42) is a quartz-stabilized one Oscillator and the oscillator frequency to the clock frequency of the counter (Zl, Z2) contains reducing frequency divider. 11. Traffic light according to one of claims 4 to 10, d a d u r c h it is not indicated that the power supply connections of the numeric display (28) and the associated circuit arrangement (30) with the interposition of a Overload protection (32) with the power supply (network 22) of the traffic light (10) are connectable. 12. Traffic light according to claim 11, d a d u r c h g e -k e n n z e i c h n e t that the circuit arrangement (30) one on one of one outside of the traffic light housing (12) arranged control center (20) on the supply current modulated signal announcing a change in the traffic light phase duration Receiver demodulator (60) contains - with its output signal the reset inputs (R-) of the two counters (zl, Z2) resetting the counters to the initial state Zero can be applied. 13. Traffic light according to one of claims 4 to 12, d a d u r c h it is noted that the numeric display (28) has more than one light-emitting diode hidden Contains display elements in a 7-segment arrangement or a dot matrix arrangement. 14. Traffic light according to one of claims 4 to 13, d a d u r c h it is not indicated that the numeric display (28) has three digits. 15. Traffic light according to one of claims 4 to 14, d a d u r c h g e k e n n n n z e i c h n e t that the numeric display (28) with the associated circuit arrangement (30) in one of the traffic light housing (28) separated on a traffic light pole or the like. in immediate Near the traffic light housing (12) above the red lamp (14) attachable housing (26) is arranged, and that the cable connections between the traffic light housing (12) and the housing (26) of the numeric display (28) as detachable screw or plug connections are trained.