GB2077475A - Apparatus for metering, electronically controlling, and displaying vehicle parking time - Google Patents

Abstract

An apparatus is described which fulfills the function of a vehicle parking meter which differs from previous mechanically operated meters in that the coin registration, timing, and display functions are performed wholly by electronic circuitry. Preferred form of display is of the liquid crystal type. The power consumption of the apparatus is very low as it consists predominantly of CMOS circuitry and power is provided by a battery whose charge is maintained by light-activated solar cells. Functions additional to those provided by mechanical meters are provided and include cash totalization, cash display, settable parking charge per hour, settable parking periods, and provision for providing digital information from the meter to an external data-recording device. Embodiments are described incorporating the RCA 1802 and RCA 1804 microprocessor together with peripheral circuitry. <IMAGE>

Description

SPECIFICATION Apparatus for metering, electronically controlling, and displaying vehicle parking time The present invention relates to the sale by registration of coinage of vehicle parking time. Up to the present time parking meters have been conventionally powered by wound springs driving clock-work gear trains and indicating flags or pointers. Coin entry has been by gravity or assisted by motive power provided by the clock-work mechanism. A specification for such clock-work parking meters is given in British Standard 4684:1971 'Specification for Clock-work Parking Meters' published by the British Standards Institution.

Clockwork parking meters although quite effective from the users' point of view suffer from several disadvantages to the operating authority. These disadvantages are imposed essentially by the clockwork and mechanised nature of the apparatus. Most obvious is the necessity to perform periodic windings of the spring mechanism which can provide operating power for only an order of a week or so.

The periodic winding of the springs is time consuming and on occasion when springs break be hazardous to the winding personnel. A second disadvantage is that the inherent mechanical nature of the apparatus means that mechanical changes must be made in the gearing and controlling mechanism and even the indicating dial for a parking meter to be usable for a variety of areas, where the length of standard period, excess period and penalty period can vary, as well as the rate per hour charged for parking time. Moreover in the present times of monetary inflation parking charges need to change more frequently and the time and effort required in changing or modifying the meter mechanisms is wasteful and expensive.

It is a feature of the subject of this patent, an Electronic Parking Meter, that the length of parking periods, parking cost per hour and other operating characteristics can be set on the apparatus according to the position of variable switches or according to information stored within electronic memory in the apparatus. In either case changes to the operating characteristics of the meter involve no mechanical alteration to the mechanism. This means that one meter serves for any location no matter what the parking periods are or how they or price per hour of parking time are changed. Changes in parking rate are easily accommodated by just altering the setting on a switch or switches accessible within the body of the meter.

A feature of digital circuity and particularly the circuit technoiogy known as Complementary Metal Oxide Silicon is that power consumption is extremely low. The power consumed by the electronics of an electronic parking meter need be only of the order of 1 milliwatt. If a display of the liquid-crystal type is employed drawing as little as 30 or so microamperes at 5 volts the total power consumption of the device using gravity coin-feed remains at the 1 milliwatt level. This means that the electronic parking meter possessing a readout of time in figures rather than a scale and pointer can run for many months on a single battery..

Furthermore since power consumption is so low it is possible to use a rechargeable battery of nickelcadmium or other type which can be continuously charged from an array of photovoltaic cells positioned in a window in the body of the parking meter.

Such a parking meter is able to operate virtually indefinitely without attention of any kind save as to emptying the coin collecting box. The novel electronic parking meter is thus a most versatile and effective means of controlling and charging for vehicle parking time. The electronic parking meter allows a number of facilities which are not possible with mechanical meters. The meter contains a time reference most conveniently provided by a quartz crystal timing oscillator. The apparatus may also be impiemented so as to be settable to the absolute day, time and date.The meter is then able to operate at different charging rates according to the time of day, to allow free parking on certain days and to disallow parking at certain other times and days under control of information stored in the form of switch settings or within an electronic memory associated within the meter.

Anotherfacilitywhich is provided is that of monitoring the use of the meter by totalizing the time the meter is used and the cash that is taken since last the meter was emptied or reset and also to use its display to indicate these quantities under control of switches inside the case of the apparatus.

A further facility is that of being able to transmit information from plug or socket in the apparatus provided for the purpose to a data recording apparatus. In this way every meter on being emptied can provide a record of the meter serial number or identifying number, together with the cash deposited since last being reset and any other information required by the operating authority and programmed into the apparatus.

The electronic parking meter can contain electronic circuitry consisting of dedicated electronic devices but most effective and flexible is apparatus embodying a microprocessor or a microcomputer operating according to a stored programme of instructions.

It is an object of the present invention to provide apparatus performing the function of a parking meter and comprising electronic circuitry responsive to electrical signals generated by the entry of coinage, totalizing and calculating circuitry responsive to these signals so as to register the purchase of periods of parking time, switches or other means for altering the cost per hour, parking periods, and other operating characteristics of the apparatus, indicating means operable to display the parking period as well as total cash taken by the apparatus. The apparatus also provides facility which may be employed to set the timing device to absolute time of day, day and date and be responsive to such absolute time so as to vary the characteristics and display of the meter according to the time, day and date.Further the facility is provided enabling the apparatus to transmit to a date recording device statistics and totals requested by the apparatus indicative of the total cash taken, an identifier of the particular meter providing the information, and other information relevant to the recent use and operation of the apparatus.

In one embodiment of (he invention power is provided by a conventional battery of approximately Svolts rating.

In another embodiment of the invention powerto operate the apparatus is provided by natural sunlight falling on an array of photovoltaic solar cells whose current output is used to maintain the charge of a rechargeable battery of nickel-cadmium type.

Various embodiments employ various display devices. A favoured embodiment employs liquidcrystal displays of the seven-segment type which are capable of displaying all numbers and a restricted number of alphabetic symbols. Such a favoured embodiment employs adequately a set of four such alphanumeric indicating devices with decimal points between the four numbers. Such a display is suficlient to indicate parking time (standard, excess, penalty) and totalized cash taken by the apparatus.

An embodiment is possible which performs only the functions of the mechanical clock-work parking meter. Although such an embodiment is possible a very simple embodiment conveniently incorporates switches alterable to set the operating characteristics of the apparatus such characteristics including the charging rate for parking time and the duration of the parking periods.

In a further embodiment controls are situated within the body of the apparatus to effect a display of total cash taken by the apparatus since last reset.

In one embodiment a controlling switch enables the apparatus to ignore parking time unused by the previous user particularly if such unused parking time is less than that purchased by the single entry of the smallest denomination of coinage accepted by the apparatus. Such a feature is not incorporated on meters of the mechanical clock-work type.

Yet another embodiment incorporates a socket to which can be attached a wire lead to a data recording device. The apparatus provides information signals to the recording device indicative of various operating statistics of the parking meter including total cash taken, a meter identifying code, time used on the meter or a restricted part of such information as required to be recorded by the operating authority.

The embodiment of the meteremploys a liquid crystal display of the transflective type as indicating device and so as to improve the legibility of the display during darkness incorporates radioactive light emitting devices typically of the type known as 'Betalights' which provide rear illumination of the display.

All embodiments of the invention can be implemented using standard integrated circuits in an appropriate circuit configuration. A preferable embodiment of the apparatus incorporates a mic roprocessorwith associated read only memory program store and random access data store together with peripheral signal input and output circuits.

Yet another form of embodiment employs a microcomputer which Itself contains program memory and random access data memory functions.

For economy of power consumption any favoured embodiment employs electronic devices of the complementary metal oxide silicon type thereby allowing extended operation to be possible from a small battery or a rechargeable battery whose charge is maintained by the current provided by an array of photovoltaic solar cells.

A favoured form of embodiment employs as time reference a quartz crystal whose natural frequency of oscillation is 32.768 KHz, the advantage of such a frequency being that it can be conveniently divided by a factor of 232 to give a pulse once per second and a microprocessor or microcomputer driven at this frequency consumes a minimal amount of power.

Features and advantages of the present invention will become apparent from the following description of embodiments thereof, given by way of example with reference to the accompanying drawings in which Figure 1 is a diagram illustrating the functions performed by the apparatus.

Figure 2 is a diagram illustrating the component parts incorporated in the apparatus.

Figure 3 is a diagram illustrating one embodiment of a solar powered power-supply for the apparatus.

Figure 4 is a block circuit schematic of an embodi mentofa comprehensive form of the invention.

Figure 5 is a block circuit schematic of an embodiment of the invention incorporating a restricted number of features incorporating a microprocessor.

Figure 6 is a block circuit schematic of an embodiment of the invention similar in function to Figure 5 where the microprocessor is replaced by a microcomputer embodying a pre-programmed program memory.

Figure 7 is a detailed circuit diagram of the embodiment illustrated in the block schematic of Figure 5.

Figure 8 is a diagram of the structure of the logical functions performed by the apparatus illustrated in Figure 7 when in various states of use.

Figure 9 is a simplified flow diagram illustrating the sequence of operations performed by one embodiment of the apparatus in conjunction with its stored program of instructions.

Figure 1 illustrates the principal functions which are incorporated in a complete embodiment of the invention. The apparatus essentially incorporates a calculating function, 1, responsive to information function, 2, and control function, 3, an essential relative time reference, 4, an absolute time setting, 5, which can be employed according to the needs of the operator, an essential means for putting out information to the user in the form of a display, 6, and a means for recording information, 7, from the apparatus if so required by the operating authority.

Figure 2 illustrates how the functions of Figure 1 are implemented in a general embodiment employing as a calculating and controlling element a microprocessor, 8. In this form of embodiment parking period durations, charging rate and other essential operating information, 9, are provided as operating constants in the form of binary electrical signals accessible by the circuits of the microproces sor. For convenience these signals can be the outputs of a set of binary or multicontact switches.

Coin entry controls, 10, generate electrical signals detected by the microprocessor on the occurrence of coin insertion. Relative time reference is provided by a crystal, 11, driving a clock circuit, 12, which serves as the operating clock for the microprocessor.

Division of the clock frequency by a counter, 13, in conjunction with, or possibly within the microprocessor, establishes a pulse repetition at a convenient known rate such as once per second.

The microprocessor operates in conjunction with a stored program device, 14, and a random access memory device, 15, to provide signals to drive the display device, 16, which for preference is an electronic numeric or alphanumeric indicating device of 7-segment or 35 dot-matrix type or similar.

A data recording apparatus, 17, may be attached to the apparatus at intervals so as to record required operating information providable by the microprocessor. Figure 3 is a diagram illustrating one form of embodiment of a light-powered power supply providing approximately 1 charging current to a nickel-cadmium rechargeable battery. An array of 16 solar cells, 21, each providing 0.5V is sufficient to provide a continuous discharge current of 200yA at a nominal voltage of 5.0 volts to the electronic circuits of the parking meter, 22. These circuits are, for preference, of the low power consuming CMOS type, and the display of liquid crystal display type consuming a very small amount of power. A battery protection diode prevents discharge of the battery at times when owing to darkness minimal light falls on the solar cells.

Figure 4 is a schematic of a circuit diagram of a particular embodiment of the invention which effects all the equipment functions shown in Figure 2. Central to this particular circuit embodiment is the low power CDP1802 CMOS microprocessor, 24, used to effect the controlling and calculating functions of the apparatus. > The microprocessor employs an 8-bit parallel data bus to access 64 bytes of random access memory, 25, 2048 bytes of program memory, 26, and five nominally 8-bit wide data input and output ports. Other embodiments could employ diferent sizes of RAM, ROM, or different numbers and arrangements of ports.

Control of information fed onto the data bus is exercised in the case of memory by the memory address bus, 28, which provides data address in two sequential 8-bit bytes A0 to A7 and A8 to A15. In this embodiment only A0 to A10 are employed, A8 to A10 being latched off the three low-order bit wires by the latch, 29, latched by a timing pulse TPA generated by the microprocessor. Information is fed onto the data bus by the ports 0 to 4 under control of the three N-line signals NO, N1, N2 via the 3 to 8 way decoder, 30. One of the Al to A8 lines is enabled by the N lines so that only one of the ports is enabled at a time as required.The ports gate information from various switches indicative of charging rate, parking periods meter identification numbers, cash entry, use/out of use, unused time, free or not free conditions.

The display driver, 3i, is used to store information for display sent to it by the 0 output of the microprocessor. In this embodiment the information provided is a series sequence of binary signals indicative of the on/off state of each segment of the display, 32. Other embodiments are possible whereby the information provided is parallel fed from the data bus and representing either the segments themselves or or in an embodiment incorporating a display decoder driver the information can be in a standard ASCII 4-bit numeric or 7-bit alphanumeric form.

In this particular embodiment the display is of liquid crystal type incorporating 4 7-segment displays and 3 decimal points. These characters are employable to indicate numbers and a variety of other symbols including some alphabetic symbols, plus sign, and minus sign. The numeric symbols are utilised to display numeric indication of time, cash taken and other required numeric information. The non-numeric symbols are conveniently employed to indicate such parameters as P for penalty, E for excess, OFF when the meter is out of use and a variety of other displays. The display driver is loaded and clocked by two of the A signals A8 and A7. A back-plane drive signal is provided from one of the outputs from the counter, 33, being a square wave of 32Hz.This is a convenient frequency with which to drive the display being sufficiently high to avoid flicker and sufficiently low to minimize current consumption to a figure of the order of 30 microamperes. The display is of a legible size being conveniently 1/2 inch high or 1 inch high. Although in this embodiment for convenience and ease of implementation and economy of power consumption a 4-digit 7-segment display is employed displays of the 35-dot matrix type are possible, capable of displaying the full range of alphanumeric symbols. Other embodiments employing light emitting diode indicators or relay driver electromechanical indicators can be incorporated in the apparatus by employing a modified form of drive circuitry to that shown for the liquid crystal display.

One disadvantage of liquid crystal displays is that they are not inherently light emitting as for exampie are light emitting diode displays. Illumination of the liquid crystal displays can most conveniently be provided by employing displays of the transflective type which both reflect and transmit incident light and illuminating such a display from the rear using radioactive light sources of the 'Betatron' or other type.

A clock generator is provided in this embodiment by a crystal, 34, connected to an inverting feedback amplifier internal to the microprocessor on the CLK and XTAL connections. The frequency is chosen to be a convenient frequency for time reference generation and in this particular embodiment is 32.768 Hz or or 215Hz. Time reference is conveniently achieved in this embodiment by counting the TPB pulse (clock frequency . 8) in the 212 counter, 33. The resultant pulse driving the external flag line EF1 occurs once per second and can be conveniently employed by the microprocessor to derive minutes and hours elapsed.

In this embodiment three other external flag lines are used as follows. EF4 is employed to signal whether the current display should be of cash or of time. In this embodiment a conact switch in the body of the apparatus ensures that the meter cannot display cash when the case is closed.

The EF2 and EF3 lines are used in this embodiment in association with the Q line to provide a data recording apparatus connected by plug and cable to the apparatus with operating statistics and information gathered by the microprocessor during normal use. Information indicative of total cash-take since last reset, total time purchased, a meter-identifying number are made available so that the external data recording apparatus can record them; other information can be readily made available as required by modification to the stored program of instructions.

EF3 is used as a data output request signal and EF2 is used as a data acknowledge signal provided by the external recording apparatus.

This embodiment shows serial provision of data, simple modification allows data to be provided in a parallel 8-wire form or in any other convenient format as required. ~~~~ In this embodimentthe interrupt line INTis employed to ensure a fast response to coin entry which may cause a relatively brief signal on the port 0 lines and also for zero-cash which is a push-button contact being possibly of relatively short duration.

Response of the microprocessor to an interrupt is to examine the conditions of the port zero lines and to effect the necessary action accordingly.

Figure 5 shows a restricted form of the embodiment just described with reference to Figure 4. In this embodiment fewer facilities are provided. The same combination of random access memory, 35, program read only memory, 36, microprocessor, counter, 38, and display driver, 39, driving display, 40, are employed in combination with two input ports, port 0 (41) and port 1 (42). The ports are again enabled on to the data bus by the 3 to 8 way decoder driven by the three N-lines.

Facilities omitted in this embodiment are those of provision for driving an external data-recording apparatus. Some of the EF lines are used instead for status signalling switches providing information to the microprocessor. The fact that fewer facilities are available means that the circuitry incorporates fewer components than the embodiment shown in Figure 4.

Figure 6 is yet another embodiment employing fewer components than that illustrated by Figure 5 This embodiment is particularly suited to high volume production incorporating an 1804 microp rocessor, 44, which has the program instructions masked into its internal read only memory at manufacture. The 1804 also incorporates 64 bytes of random access memory. This embodiment achieves the same functions as that of Figure 5 but is particularly economic in the number of electronic components required.

Figure 7 is a fully detailed circuit diagram of the embodiment shown in schematic form in Figure 5.

The microprocessor is an 1802 CMOS microprocessor driven by a 32 KHzcrystal. The two input ports are realized by using three hex-buffers MM70C98 (47). The program memory is stored in electrically re-programmable ultra-violet erasable memory consisting of four 512-byte memories, Intersil, 1M6654 (48). Random access memory is one 128 byte RCA CDP1 823C (49). The N-bit decoder, 50, RCA CDP1853 drives the liquid crystal display driver Hughes Hamlyn model 3906 transflective display. Back lighting is preferably provided to improve legibility in darkness. This back lighting can be conveniently provided by Betatron radioactive light sources behind or at the side of the display.

The apparatus is powered from a solar cell array charging a nickel-cadmium battery. The continuous charging current is of the order of 1 milliampere although the array of 16 solar cells can provide typically up to 40 milliamperes at 8 volts in bright sunlight. Current required by the complete apparatus is of the order of 200 microamps so this arrangement provides more or less perpetual power.

An alternative arrangement is to drive the apparatus with a conventional 5 volt dry-cell battery which could provide power sufficient for the order of one year of use.

Figure 8 is a diagram of software functions performed by the embodiment of Figures 5 and 7 when the apparatus shown is in certain states of operation. The functions shown are a typical embodiment and the apparatus could have several forms of program implementation achieving the necessary function of a parking meter. In this particular embodiment is shown firstly the RESET function which initializes the apparatus when power is first applied. S When the parking meter display reaches the end of its present penalty period the apparatus re-senses costs and time periods set on switches and displays maximum penalty period or alternatively an indication such as End. This block of functions is shown at 54.

Normal operation is shown at 55 being the state of operation where coins have bought parking time and the time display decrements once per minute. If more than the maximum parking time is purchased the display is operable to read 'Full' indicating that the user should insert no more cash, 56. The meter can be switched off by an internai switch in which case the display is operable to read 'OFF', 57.

Two types of interrupt signal may occur. The first of these is cash entry, 58, which registers the amount of cash deposited. The second of these is zeroing of the cash-totalizing register, 59, which would normally occurwhen the meter is emptied of coins, and in this implementation only occurs if the meter is set to read cash.

Figure 9 is a schematic of a particular embodiment of program instructions necessary to achieve the functions illustrated in Figure 8. There are two parts of the program, the main program,60, and the interrupt program 61. The centre of the main program is a routine to count seconds, convert to minutes and decrement the parking time register on passage of each minute.

A change to the display is required if coins have been deposited or a minute has elapsed. If the display requires changing the display driver is loaded with the new display information and latched to the display. The program then continues to count seconds if parking time has not expired. If the parking time has reached maximum penalty period the program branches to a point just after RESET which effects a reading of the cost and time period readings which may on occasion be changed by the operating authority. The inerrupt program is followed whenever a coin is deposited or the zero-cash button is depressed. If zero-cash is pressed the cash-total register is cleared if the meter is switched to displaying cash. The operation then resumes according to the next instruction in the main program being followed before the interrupt.If a new coin has been deposited the denomination is determined and an appropriate flag is set for the detection on return to the main program loop after interrupt.

Figure 9 is a representation of one of many possible ways of structuring a program to achieve the same objectives. The stored program can easily be modified to implement any other particular structure.

The embodiments described with reference to Figures 1 to 9 incorporate in all cases electronic controlling and calculating circuitry which controls only one parking position. It is quite a simple modification to the embodiments described to allow the electronic circuitry, usually implemented by a microprocessor, to control the parking of vehicles in two or several parking positions. In this case there may be one coin entry mechanism settable by the user to apply to parking time for his particular vehicle position or there may be a number of separate coin entry mechanisms, one for each parking position. In either case there will preferably be one indicating deyice for the parking time display or each parking position.

Claims (25)

1. Apparatus comprising a time reference, means for registering the deposition of several denominations of coinage, electronic controlling means responsive to the deposition of said coinage and sensible to timing signals derived from said time reference, electronic calculating means responsive to the deposition of said coinage registered by said controlling means so as to register the sum of periods of parking time purchased corresponding to the denomination and number of coins deposited, means whereby the controlling means and calculating means reduce the totality of purchased parking time in accordance with timing signals derived from said time reference and display means driven by electrical signals generated by said controlling means in conjunction with said calculating means in such manner as to provide legible indication.

2. Apparatus according to claim 1 where the display means are of electromechanical type.

3. Apparatus according to claim 1 where the display means are of liquid crystal display type.

4. Apparatus according to claim 1 where the display means are of light emitting diode type.

5. Apparatus according to any of claims 1 to 5 where the display means is operable to display a variety of alphanumeric and symbolic information.

6. Apparatus according to claim 1 where the controlling means is responsive to a variety of controlling switches operable to provide to the calculating means information corresponding to the price per hour of parking time the length of standard parking time period, excess parking time period and penalty parking time period.

7. Apparatus according to claim 1 where the controlling and calculating means are responsive to the deposition of coinage in such a way as to form a total of the sum of coinage deposited in the apparatus over a period of time extending over many days.

8. Apparatus according to any of claims 1 to 7 where the display means are operable to provide an indication of parking time purchased, an indication of time into excess period and an indication of time into penalty period.

9. Apparatus according to any of claims 1 to 8 where the display means are operable to provide indication of the totality of cash deposited over a period.

10. Apparatus according to any of claims 1 to 9 incorporating a switch or switches operable to provide to the controlling and calculating means information so as to synchronize electronic timing means to the current time of day, or time and day of the week, or time day of the week and date.

11. Apparatus according to claim 10 whereby parking periods, parking times, parking rates or a combination of such quantities is modified by the apparatus according to the absolute time, date or day.

12. Apparatus according to claim 10 whereby the display is operable to include a display oftime of day.

13. Apparatus according to any of claims 1 to 12 where power is provided by a plurality of photovoltaic cells so arranged as to maintain the charge of a rechargeable battery.

14. Apparatus according to any of claims 1 to 13 where controlling means and calculating means comprise a number of interconnected digital electronic circuits.

15. Apparatus according to any of claims 1 to 13 where controlling means and calculating means comprise a microprocessor, an electronic counter, a program store, a random access memory and associated signal input and output controlling circuits or a combination comprising a selection of such said devices.

16. Apparatus according to any of claims 1 to 13 whereby controlling and calculating means comprise a microcomputer possessing an integral program memory store, integral random access memory, an integral counter and operating in conjunction with signal input and output controlling circuits.

17. Apparatus according to any of claims 1 to 16 whereby the time reference comprises a quartz crystal resonator as a controlling element in an electronic oscillator.

18. Apparatus according to any of claims 1 to 16 whereby the time reference comprises a resistive element operating in conjunction with reactive elements or elements operating as controlling elements in an electronic oscillator.

19. Apparatus according to any of claims 1 to 18 whereby means are provided for conriection of a data recording device and the transmission of stored information bytheconrolling means to the recording device.

20. Apparatus'according to claim 19 whereby the information transmitted comprises signals indicative of parking time sold, cash taken by the apparatus and statistics indicative of the use of the apparatus or a selection of such information.

21. Apparatus according to any of claims 1 to 20 whereby the parking time cost per hour parking periods and any other information controlling the operation of the apparatus are stored in programmable pre-programmed or random access memory.

22. Apparatus according to any of claims 1, 2 or 3 whereby illumination of display means is effected by a radioactive light-emitting device.

23. Apparatus according to any of claims 1, 2 or 3 where the display means is inherently self illuminating.

24 Apparatus according to any of claims 1 to 23 where a single controlling and calculating means is so organised as to control the display of a number of parking time indicating devices appropriate to a similar number of vehicle parking positions and in conjunction with a similar number of coin sensing devices or a single coin sensing device operable by selection means to purchase parking time in one of several parking positions.

25. Apparatus for registering and controlling parking time comprising coin entry registration means, controlling means and calculating means operating in conjunction with display means and driven by electrical power supplying means so as to form an electronic parking meter as hereinbefore particularly described with reference to the drawings 1 to 9 accompanying the provisional specification.