GB1602274A - Electronic taximeter - Google Patents

Description

(54) AN ELECTRONIC TAXIMETER (71) We, MICROSYSTEM DESIGN LIMITED of Fleets Industrial Estate, Willis Way, Poole, Dorset, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an electronic taximeter.

According to this invention, there is provided an electronic taximeter which includes a microprocessor system including a microprocessor programmed for computing, from incoming information, data relating to the fare, the taximeter being arranged for displaying data relating to the fare as a result of such computation, in which taximeter the microprocessor stores parameters, in dependence on which the said computation is carried out using such incoming information, and the microprocessor is such that and the taximeter is arranged such that, the said stored parameters can be changed purely electronically, there existing the ability for writing new parameters into memory means of the microprocessor and thereby erasing parameters previously stored, without the need to exchange any part of the taximeter.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a block diagram of an electronic taximeter, Figure 2 shows a face of a gas plasma discharge display device of the taximeter, Figure 3 shows a front of the taximeter, and Figure 4 is a block diagram of a modifier for use with the taximeter.

Referring first to Figure 1, the electronic taximeter comprises: 1) a central processor unit CPU, 2) input/output logic circuitry CL, 3) a read only memory ROM, 4) a store TCS for tariff constants and a store TDF for distance and fare totals 5) a crystal controlled clock CC, 6) a random access memory RAM, 7) a display device D, 8) circuitry ADL and CDL for driving the display device, 9) a power supply unit P together with a secondary power supply in the form of a stand-by battery B, 10) circuitry ELD for driving external lamps, and 11)) auxiliary circuitry (including push-button control switches marked "Mode", "Extras ' and "Total" and circuitry (not shown) for suppressing their contact bounce. These parts are housed in a case of metallic material which prevents the ingress of dust and humidity.This case may be mounted in a dashboard, or on a bracket, in a vehicle.

The taximeter is suitable to be connected with a gearbox transducer G, as shown, and also a modifier device, which device is used to program the taximeter with information required for its operation.

The system comprising the central processor unit CPU, the input/output control logic circuitry CL, the read only memory ROM, the stores TCS and TDF for tariff constants and distance and fare totals, the random access memory RAM and the crystal controlled clock CC, form a microprocessor. This system collates information, such as time and distance information, when tae taximeter is being used, and processes it. The processing of the information is controlled by an operating program stored in the read only memory ROM which the central processor unit CPU is designed to execute. The processed information is displayed in illuminated form by the display device D. Time information is provided by the crystal controlled clock CC.

The random access memory RAM is connected with the central processor unit CPU and it stores working values for the taximeter during operation, such as information relating to the mode of the taximeter (for example, " For Hire" or "Hired").

Also connected with the unit CPU are the memory ROM (which stores the operating program for the taximeter and the stores TCS and TDF for tariff constants and distance and fare totals. The unit CPU uses information stored in the RAM and the stores for tariff constants and distance and fare totals during execution of the operating programe. This information can be altered by use of the modifier device.

The display device D is a gas plasma discharge display. It is connected with the driving circuit ADL and CDL which provides an interface between the unit CPU, the input/output control logic circuitry CL and the display device D. The driving circuitry ADL compirses logic circuitry for driving the display anodes and the circuitry CDL comprises logic circuitry for driving the display cathode, both of which are supplied with anode and cathode multiplexing signals respectively from the input/ output control logic circuitry CL, which also supplies display blanking signals to the anode drive logic circuitry ADL. Processed information to be displayed is supplied from the unit CPU to this driving circuitry.

The display device of taximeters must, to conform with the requirements of the relevant authorities, give information relating to the fare, the charge for any extras incurred, and the state of operation of the taximeter (e.g. "For Hire", "Hired", "Tariff Rate", or "Stopped").

Information is also provided representing the total number of miles travelled, the total number of fare increments registered in all tariff rates and the total number of extras charged.

Referring to Figure 2, there is shown means for providing illumination of areas adjacent permanent characters and also providing for the display of symbols, the majority of which are varying symbols, whereby compulsory information and also optional information may be displayed in illuminated form in the electronic taximeter. The substrate 1 of the gas plasma discharge display device D is selectively masked at each of regions 2 to 8 with seven plasma lands to provide a seven segment display in each case, so that digits (such as those shown in Figure 3) may be displayed in illuminated form. These digits formed by the plasma land segments at regions 2 to 8 must, to conform with the requirements of the relevant authorities, have a minimum height of 10 mm. To the right of regions 2 to 8, seven rectangular lands of plasma have been masked on to the substrate at regions 9 to 15.To the left of regions 6 to 8, four groups of seven plasma lands, at regions 16 to 19 respectively, have been masked on to the substrate to provide a seven segment display in each case, to enable 4 digits (such as those shown in Figure 3) to be displayed.

The digits at the regions 16 to 19 must, to conform with the requirements of the relevant authorities, have a minimum height of 4 mm. A decimal point 26 is located between regions 3 and 4 and a further decimal point 27 is located between regions 6 and 7, the decimal points being of plasma lands masked on to the substrate.

Six rectangular lands of plasma, at regions 20 to 25, have been masked on to substrate to the left of regions 2 to 5. Referring now to Figure 3, in the complete taximeter the substrate 1 is behind a screen 28 on which permanent characters (mainly letters) have been applied by silk screen techniques. Since this screen 28 is removably affixed to the gas plasma discharge display device D, it is possible to change the permanent characters which identify transient information -- to allow for different currencies and/or languages, for example.

The plasma lands at regions 9 to 15 and the plasma lands at regions 20 to 25 are selectively energised, to selectively indicate the permanent characters applied to the screen 28 adjacent to them, this selec tive indication occurring according to the state of operaion of the taximeter. Also, the associated plasma land segments at regions 16 to 19 are selectively energised to provide visible digits.

Digits provided by the plasma land segments at regions 2 to 8 are visible during operation of the taximeter, except when it is in the "For Hire" mode, each digit representing a number from 0 to 9 by the energisation of particular ones of the seven plasma land segments in each case. The digits at regions 2 to 5 represent the fare, while the digits at regions 6 to 8 represent the charge incurred for extras. A group of two digits at regions 16 and 17 is also visible when the taximeter is in the "For Hire" mode. These digits indicate the tariff code which signifies the tariffs and the tariff rates with which the taximeter has been programmed. A visual indication is therefore provided for the relevant authorities that the taximeter ie operating with the correct charging constants.

In use, the taximeter is controlled by the operation of the three push button control switches 31, 30 and 29 located at the front of the taximeter below the screen 28 and being respectively the "Mode", "Extras" and "Total" switches of Figure 1. Pressing of the "Mode ' switch 31 causes the taximeter to switch from its state of operation, or mode, at that time to the next mode. This switching occurs in a nonreversible cycle comprising between 3 and 6 modes: e.g. "For Hire", "Hired" (up to four different charging rates), and "Stopped" and the current mode is indicated by illumination of the appropriate one of plasma lands at regions 9 to 15 respectively.

The "Hired" mode comprises four individual tariff rates, denoted by the permanent characters, for example "Stan dard", "Night", "Holiday" and "discount", and applied of silk screening to the screen 28 adjacent to the four recttangular lands which make up the plasma lands at regions 12, 13, 14 and 15.

"The Extras" switch 30 has three functions, according to the mode of the taximeter. In the "For Hire" mode, the pressing of this switch 30 causes all the segments of digits on the display and the plasma lands at regions 9 to 15 to be continuously energised until the switch 30 is released. This function serves as a test to ensure correct illumination of each of the plasma land segments of the seven land segments forming the digits in each case.

In the "Hired" mode, the pressing of the switch 30 causes a fixed charge increment to be registered and displayed by the taximeter. The value of this increment is determined by the tariffs with which the taximeter has previously been programmed.

In the " Stopped " mode, the pressing of the switch 30 causes the charge for any extras incurred during a journey (as displayed by the digits at regions 6 to 8) to be added to the fare for that journey. At the same time, Value Added Tax (VAT) is determined by the taximeter and added to the total fare for the journey. This total fare is displayed by the digits at regions 2 to 5, which previously displayed the fare for the journey less any extra charges and VAT.

Pressing of the "Total" switch 29 causes the following sequence. First the plasma land at region 20 is energised and the total number of miles travelled is displayed by digits at regions 16 to 19; then the plasma land at region 21 is energised and the total number of "engaged" miles is displayed by digits at regions 16 to 19; then the plasma land at region 22 is energised and the total number of trips (or hirings) is displayed by digits at regions 16 to 19; then the plasma land at region 23 is energised and the total of the "Extras" charged as a number of given currency units is displayed; then the plasma lands at regions 24 and 12 are energised and the total of the fares charged at standard rate is displayed; then the plasma lands at regions 24 and 13 are energised and the total of the fares charged at night rate is displayed; then the plasma lands at regions 24 and 14 are energised and the total of the fares charged at holiday rates is displayed; then the plasma lands at regions 24 and 15 are energised and the total of the fares charged at discount rate is displayed; then the plasma lands at regions 25 and 12 are energised and the total of the fares charged at the double tariff standard rate is displayed then the plasma lands at regions 25 and 13 are energised and the total of the fares charged at the double tariff night rate is displayed; and finally the plasma lands at regions 25 and 14 are energised and the total of fares charged at the double tariff holiday rate is displayed. Each energisation and corresponding display lasts for about six seconds.

A push-button switch 32 is an on-off switch for switching on and off the taximeter and is the on-off switch 0 in Figure 1.

Although the taximeter is primarily powered by the vehicle battery, which is connected with the power supply unit P, provision must be made for the continued operation of the taximeter should this external (primary) power supply fail to be disconnected. This is provided by the secondary power supply comprising the stand-by battery B, for example a rechargeable cell. This stand-by battery is connected with the power supply unit P and, in the case of a rechargeable cell, is charged by the primary power supply during normal operation of the taximeter.

The primary power supply is monitored by the input/output control logic circuitry CL which, should this supply fail or be disconnected, will not permit the taximeter to switch to the "Hired" mode (from the "For Hire" mode) until power is supplied again from the primary supply.

The tariff constants store and the total distance and fares store (TCS and TDF) have their own reserve power supply, comprising a battery, which is used should both the primary and secondary power supplies described fail or be disconnected. This precaution is taken to ensure that the information stored in stores TCS and TDF is not lost.

The control switches 29, 30 and 31 already described are connected with the input/output control logic circuitry CL which is also connected via ELD to electrical wiring to connectors for external lamps (the "For Hire" and "Hired" lamps).

A connector CON is also provided for the modifier device, the connector being connected with the central processor unit CPU.

The transducer G is mounted at the rear of the vehicle gearbox and is driven by a rotary shaft S which extends from the gearbox. This transducer comprises a magnetised rotor and a magnetically operated switch, both of which are housed in a sealed case. The magnetised rotor is driven by the shaft S and the movement of the magnetic field with respect to the magnetically operated switch causes the latter to produced a signal made up of a train of pulses, known as distance pulses. The transducer can produced more than 1000 of these pulses per mile travelled by the vehicle, thus providing the distance information required by the microprocessor system.

The distance pulses are supplied via a sheathed multicore cable to the input/ output control logic circuitry CL of the taximeter. One of the cable wires supplies a signal produced by the transducer, known as the transducer monitor signal, which is monitored by the microprocessor system.

Should the cable be broken, processing of information is stopped, i.e. execution of the operating program ceases. In this case, normal operation of the taximeter does not resume, even if the cable is reconnected or the transducer functions again, until the taximeter has been especialy reset.

At the beginning of a journey hired by a passanger, the taxi driver first presses the mode switch 31. This switches the taxi meter from the "For Hire" mode to the "Hired" mode, these modes being indicated by illumination of the plasma lands at regions 9 and 10 respectively.

The digits at regions 2 to 5 initially dis play a minimum fare, with which the taximeter has previously been programmed.

The digits at regions 6 to 8 remain at zero throughout a journey, unless any extra charges are incurred and are recorded by the taxi driver by the pressing of the "Extras" increment switch 30.

During the course of the journey, time and distance information is collated by the taximeter microprocessor system and the calculated fare displayed by the digits at regions 2 to 5. These digits indicate increases of the fare as the journey progresses.

Should the taxi be travelling at a speed of less than a given speed, say 6 m.p.h., the fare is charged according to the time during which the taxis hired, and not the distance it travels.

When the journey is completed, the taxi driver presses the "Mode" switch 31 to switch the taximeter to t'ne "Stopped" mode, which is indicated by energisation of the plasma land at region 11. The taxi driver can then determine the total charge for the journey by pressing the "Extras" increment switch 30, as already described.

The modifier device used with the taximeter (see Figure 4) comprises an electrically operated 80 column punched card reader CR, a microprocessor M and some control switches CS and indicator lamps IL, all housed in a case. The card reader includes a drum which is designed to hold a standard 80 column punched card and which is rotated by an electric motor, transverse to a bank of opto-electronic detectors.

This bank of detectors is connected with the microprocessor. The modifier device is connectable to the connector CON of the taximeter via a connector CON' and a multicore cable which includes wires for carrying signals to and from the modifier device.

To program the taximeter with new information, a standard 80 column card is punched with data which represents the information to be stored by the taximeter, including the tariff constants mentioned earlier. This information could relate to fare increments or VAT rates, and for example it could also relate to the gearbox ratio of the vehicle in which the taximeter is installed, such information being required in order that the distance pulses supplied by the transducer may be correctly calibrated. The data punched in the card has two unique codes, one to mark the start of the data and one to mark the end of the data.

The card is placed around the drum of the card reader, the modifier device being connected by the multicore cable with the connector CON of the taximeter. The drum is rotated by the electric motor until the code marking the start of the data is read by the opto-electronic detectors. These detectors are energised and produce an electrical signal comprising a series of pulses corresponding to the data punched in the card. These pulses are supplied to the modifier microprocessor where they are stored.

The microprocessor checks these pulses to see that there are the correct number between the start and stop codes, and that they are punched in the correct format.

If this is not so, a lamp is illuminated to inform the operator. The microprocessor then converts the data from the card into the values required by the taximeter program.

When a correct card has been read by the modifier and its data converted, the modifier awaits a signal from the taximeter central processor unit CPU to indicate that the latter is ready to accept new information. This signal is only transmitted by the unit CPU when the taximeter is in the "For Hire" mode. On receiving the signal, the modifier microprocessor supplies due to the taximeter. This data is the data punched in the card converted by the modifier microprocessor to a format comprising five binary-coded words. One of these words comprises four bits and represents part of the new information to be stored in the taximeter. The other words include instructions for the location of the four bit word in the taximeter microprocessor system.

After the transfer of data described above has been completed, the modifier checks that the reading and writing operations have been performed correctly. The modifier effects this check by instructing the taximeter to read back all of the data just transferred into the modifier microprocessor. This microprocessor samples a four bit word from a specified location and compares it with the four bit word from its own corresponding location. The words are identical if the reading and writing operations have been performed correctly, but if this is not the case, a further indicator lamp is illuminated to inform the operator of a fault.

Attention is directed to our co-pending Patent Application Nos. 19863/77 and 31650/77 (Serial Nos. 1602272 and 1602273).

WHAT WE CLAIM IS: - 1. An electronic taximeter which includes a microprocessor system including a microprocessor programmed for computing, from incoming information, data relating to the fare, the taximeter being arranged for displaying data relating to the fare as a result of such computation, in which taximeter the microprocessor stores parameters, in dependence on which the said computation is carried out using such incoming informaion, and the microprocessor is such that and the taximeter is arranged such that, the said stored parameters can be changed purely electronically, there existing the ability for writing new parameters itno memory means of the microprocessor and thereby erasing parameters previously stored, without the need to exchange any part of the taximeter.

2. A taximeter according to claim 1, wherein the microprocessor includes: a read only memory which stores an operating program; a random access memory, a tariff constants stores and a total distance and fares store which comprise the said memory means; and a central processing unit.

3. An electronic taximeter which includes a microprocessor system, which microprocessor system is substantially in accordance with the microprocessor system herein described with reference to Figure 1 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. just transferred into the modifier microprocessor. This microprocessor samples a four bit word from a specified location and compares it with the four bit word from its own corresponding location. The words are identical if the reading and writing operations have been performed correctly, but if this is not the case, a further indicator lamp is illuminated to inform the operator of a fault. Attention is directed to our co-pending Patent Application Nos. 19863/77 and 31650/77 (Serial Nos. 1602272 and 1602273). WHAT WE CLAIM IS: -

1. An electronic taximeter which includes a microprocessor system including a microprocessor programmed for computing, from incoming information, data relating to the fare, the taximeter being arranged for displaying data relating to the fare as a result of such computation, in which taximeter the microprocessor stores parameters, in dependence on which the said computation is carried out using such incoming informaion, and the microprocessor is such that and the taximeter is arranged such that, the said stored parameters can be changed purely electronically, there existing the ability for writing new parameters itno memory means of the microprocessor and thereby erasing parameters previously stored, without the need to exchange any part of the taximeter.

2. A taximeter according to claim 1, wherein the microprocessor includes: a read only memory which stores an operating program; a random access memory, a tariff constants stores and a total distance and fares store which comprise the said memory means; and a central processing unit.

3. An electronic taximeter which includes a microprocessor system, which microprocessor system is substantially in accordance with the microprocessor system herein described with reference to Figure 1 of the accompanying drawings.