1、ABSTRACTIn this paper, a multi-channel taximeter that is able to deal with more than one passenger simultaneously is proposed.In order to demonstrate the theory of operation of the proposed system, a complete design for an experimental three-channel taximeter (whose prototype has been built under gr

2、ant from the EgyptianAcademyfor Scientific and Technological Research> is presented.System location, outline, block diagrams as well as detailed circuit diagrams for the experimental taximeter are also included.1. INTRODUCTIONTransporting people in the morning from their homes to their works and

3、back in the afternoon has become a big problem in big cities especially in undeveloped countries. As a partial solution of this problem, the authorities in some countries had, unofficially, left the taxicab drivers to carry different passengers to different places at the Same time. For example, a ta

4、xicab with four seats may carry four different passengers without any relation between them except that their way of travelling is the same.Accordingly, it has become very difficult to rely on the present conventional singlechannel taximeter to determine the fare required from each passenger separat

5、ely. Accordingly, an unfair financial relation was created between the taxicab driver, owner, passengers and the state taxation department.Under these circumstances, taxicab drivers force the passengers to pay more than what they should pay. In some cases passengers had to pay double fare they shoul

6、d pay. With the present conventional single-channel taximeter, taxicab owners are not able to determine the daily income of their taxicab.In some cases (a taxicab with four seats> they may only get one quarter of the income of the taxicab (collected by the taxicab driver>. From which they shou

7、ld pay the salary of the taxicab driver as well as the cost of fuel, minor and major repairs in addition to the car depreciation. As a matter of fact the position of the taxicab owners is not so bad as it seems. A general agreement has been reached between the taxicab drivers and owners such that th

8、e drivers should guarantee a fixed daily income to the owners as well as the paying for the cost of fuel as well as the minor repaires. Even though the taxicab drivers still share the large portion ofthe income of the taxicab.Also with the presence of the single-channel taximeter, it has become very

9、 difficult for the state taxation department to know the yearly income of the taxicab and accordingly it has become very difficult to estimate the taxes to be paid by the taxicab owners.In order to face this problem, the state taxation department had to impose a fixed estimated taxes for each seat o

10、f the taxicab whatever the income of the taxicab. In this paper, we introduced a multichannel taximeter that can deal with more than one passenger simultaneously. I t should be pointed out that by the term passenger we mean a one person or a group of related persons. I t should also be pointed out t

11、hat our proposed multi-channel taximeter is not, simply, a multi display readouts. As a matter of fact it contains logic circuits that automatically changes the fare per killometer of travelling distance or per minutes of 'waiting time according to the number of passengers hiring the taxicab. In

12、 the following part and as an example, we will present a complete design for a three-channel taximeter.Block diagrams as well as detailed circuit diagrams of the experimental three- channel taximeter are also included. A prototype has been built under grant from the EgyptianAcademy for Scientific an

13、d Technological Research.2. AN EXPERIMENTAL THREECHANNEL TAXIMETERTheory of operation of our experimental device to work as an electronic digital taximeter is based on t h e fact thathe speedometer cable rotates one revolution for each meter of travelling distance.Accordingly, if the speedometer cab

14、le is coupled with a speed sensor that generates a single pulse for each meter of travelling distance, then our taximeter could be three up counter modules associated with a speed sensor unit.However, our experimental taximeter is not simply a three display readouts. As a matter offact it contains l

15、ogic circuits that automatically changes the fare per kilometer of travelling distance or per minutes of waiting time according to the number of passengers hiring the taxicab. The device may be splitted into two main parts: The first is the speed sensor unit which may be located anywhere in the taxi

16、cab such that an easy coupling to the speedometer cable can be achieved. The second unit contains the main electronic circuit, the displayand control panel. The unit should be located somewhere in front of both the driver and the passengers.A possible components locations is shown in Figure 1.A. Spe

17、ed Sensor UnitThe main function of this unit is to supply train of pulses whose frequency is proportional to the angular rotation of the wheels. A possible form of a speed sensor is shown in Figure 2.If may consist of a tj.pica1 permanent magnet sine wave generator with its output connected to a pul

18、se shapping circuit (two general purpose silicon diodes, 1K ohms resistor and a schmit trigger inverter>.In order to find some way to detect the movement of the taxicab, the output of the sine wave generator is rectified through a general purpose silicon diode Dl then smoothed by a 1000 F capacit

19、or. The output voltage at terminal Q is then limited to the value of 4.7 volts by using a Ik ohms resistor as well as a zener diode ZD. The level of the voltage at terminal Q would be high whenever the taxicab is moving and will be zero otherwise. This voltage can be used for the automatic switching

20、 from distance fare to time fare.B. Main Electronic and Display Unit A suggested shape for the main electronic and display unit is shown in Figure 3. The control and display panel contains all ' controls necessary for operating the taximeter as well as four readout displays. The first channel wi

21、ll give the sum of money required from the first passenger, while the second and third readouts are for the second and third passengers, respectively. The fourth readout will give the total income of the taxicab.The contents of the last readout should be nonvolatile and be able to be retained even d

22、uring parking the taxicab. The channel rotary selector switchs 1 , 2 and 3 have fully clockwise/anticlockwise positions. In the fully anticlockwise position, the counter of the corresponding readout is blancked and disabled.In the fully clockwise position, the counter is unblanked, cleared to zero a

23、nd enabled to be ready for counting the sum of money required from the first, second and third passengers, respectively.Pushing the total sum pushbutton 4 unblanks the fourth readout enabling any person to retain the readout corresponding to the total income. After the release of the pushbutton, the

24、 fourth readout will be blanked again. This unit also contains the main electronic circuit which will be fully described in the following section.3. DESCRIBTION OF THE MAIN ELECTRONIC CIRCUITThe general block diagram of the main electronic circuit is shown in Figure 4. It consists of five subcircuit

25、s designated by the symboles CTI up to CT4supporting circuits, these are: The number of passenger deticition circuit CTI, travelling distance scaling circuit CT2, waiting time scaling circuit CT3, circuit CT4 which generatesclock pulses for the display circuit.A. Number of Passengers Detection Circu

26、it CT1 As shown from the general block diagram, the circuit CTI has three inputs I, 2 and 3 as well as three outputs J, K and L. The function of the circuit is to supply a high level voltage at terminals J, K or L if and only if one, two or three passengers are hiring the taxicab, respectively. The

27、term passenger, here, means one person or a group of related persons. When a passenger is getting into the cab, we simply turn on a free readout display by turning the corresponding rotary selector switch to a fully clockwise direction.This will automatically disconnect the corresponding terminal I,

28、 2 or 3 from ground. The logical relation between various input terminals I, 2 and 3 and the output terminals J, K and L is shown in Table 1.As a combinational circuit we start the design by deriving a set of boolean functions. A possible simplified boolean functions that gives minimum number of inp

29、uts to gates may be obtained from Table I.A possible logical diagram that is based on the above derived expressions is shown in Figure 5.It consists of two inverters, four 2-input AND, to3-input AND two 3-input OR gates B. Tavelling Distance Scaling Circuit CT2As shown from the block diagram of Figu

30、re 4, the circuit CT2 has four input J, K, L and E and one output M. The function of the circuit is to supply a single pulse at the output M for a certain number of pulses generated at the output of the speed sensor (certain number of meters travelled by the taxicab>, according to the number of p

31、assengers hiring the car. A suggested fare per kilometer of travelling distance is shown in colomn two of Table 2. the circuit, in this case, should supply a single pulse at the output M for every 100, 125 or 143 pulses generated at the input terminal Eaccording to the level of voltage at input term

32、inale 3, K or L, respectively.Our circuit could be, as shown in Figure 5, three decade counters, connected as a three digit frequency divider whose dividing ratios 100, 125 and 143 are automatically selected by the voltage level at terminals J, K and L, respectively.A possible circuit diagram that m

33、ay verify the above function is shown in Figure 6. It consists of three decade counters type 7490, one BCD-to decimal decoder type 7445, three 4-input AND, one 3-input ANDone 2-input AND two 3-input OR gates.C. Time Scaling Circuit CT3As shown in the block diagram, the time scalingcircuit will have

34、four inputs J, K, L and F and one output N. The function of this circuit and accordingto colomn three of Table 2 (fare per 2 minuts of waiting time> is to supply a single pulse at the output N for every 120, 240 or 360 pulses supplied at the input terminal F from the I Hz clock according to level

35、 of voltage at inputs J, K and L, respectively.Time scaling circuit would be similar to the distance scaling circuit but with different diving ratios. A Possible circuit diagram is shown in figure 7.It consists, in this case, of three decade counter type 7490, two 3-input AND, one 5-input AND, one 2

36、-input AND one 3-input OR gates.D. Circuit CT4 Which Generates Clock Pulses for Display CircuitThe function of this circuit is to supply one, two or three pulses at the output terminal R for each pulse generated at any of the terminals N or M, according to the voltage level at the input terminals J,

37、 K or L, respectively. The output P will receive a pulse for each pulse generated at any of the input terminals N or M. This function can be performed by the circuit shown in Figure 8, it consists of one ripple counter type 7493, one half of a dual JK masterslave flip-flops circuit type 7476, three

38、inverters, three 2-input AND, one 3-input AND, one 2-input OR and one 3-input OR gates. When a pulse is generated at either input terminals N or M, a high level voltage will be generated at the output Q of the flip-flop. This will g a t e t h e I Khz signal to be connected to the input A of the ripp

39、le counter as well as to the output terminal R. When one, two or three pulses are counted by the ripple counter, according to the level of voltage at the input terminals J, K and L, respectively, a high is generated to reset the counter and change the state of the flip-flopsuch that Q becomes low.He

40、nce, the 1 KHz signal is disabled to reach the outputerminal R or the input A of the ripple counter. In order to ensure the proper function of the circuit, the flip-flop should be cleared whenever a new channel is operated. This has been achieved by the input 5 and will be explained later when descr

41、ibingthe function of the channels rotary selector switchs.E. Display CircuitAs shown in Figure 2, the display panel would contain three 4-digit displays that give the sum of money required from each passenger separately as well as a one six-digit display that gives the total income of the taxicab. A

42、 possible wiring diagram for the display circuit is shown in Figure 9. Rotating any of the rotary selector switches to fully clockwise direction will supply the corresponding display by5 volts through terminals 1, 2 and 3, respectively.The corresponding display will be unblanked by supplying a low l

43、evel of voltage through terminals A, C and G , respectively. Keeping terminals 8, D and H, respectively, at low level will keep them reset to zero. The corresponding display is then enabled by removing the low voltage from terminals B, D, and H, respectively, to be ready for counting the sum of mone

44、y required from the corresponding passenger starting from zero.The counting pulses for these three displays are supplied through terminal P. The total sum display will be enabled whenever any of the three displays is enabled (this is done by a 3-inputOR gate as shown in Figure 8>. Retaining the c

45、ontents of the last display will be done by unblanking it by supplying a low level of voltage to terminal I as shown in Figure 10 b.F. Changing Over Between Time and Distance FaresIn the following part, two different methods for changing over between time andistance fares are suggested:The first is

46、to switch to time fare whenever the distance fare is less than the time fare. Hence,a simple look to fares table (Table 2> can show that time fare should be used whenever the taxicab moves with speed less than 50 m/min. A possible circuitthat can perform this switching action is shown in Figure I

47、O c. It contains one rpm limit switchand a one inverter as well as two 2-input AND gates.The contacts of the limit switch are normally closed and will be opened whenever the angular speed of the speedometer cablexceeds 50 rmp. The second alternation is to connect the input of the inverter in Figure

48、10 c. to the output terminal Q of the speedometer circuit, Figure 2.In this case, the switching into time fare will be done whenever the taxicab is at stand still.G. Function of the Rotary Selector Switches The voltage levels that should be supplied by the terminals of the rotary selector switches i

49、n order to ensure proper operation by the electronic circuit are given in Table 3. Connection of three rotary selector switches each witb four decks of five poles each, that satisfy the logic function of Table 3, is shown in Figure 10 a. Rotating any of the three switches into fully clockwise direct

50、ion will pass through five positions. The function of the rotary selector switches can be described starting from the first position passing through variousteps until reaching the final position as follows:Initial position: In this position a low voltage level is applied to terminals I, 2 and 3, thi

51、s will disconnect the 5 volts supply from the three first displays, set the three inputs of the number of passenger detection circuit CTI to low level. A low voltage level is applied to terminals 8, D and H, this is to ensure that the total income display is disabled.Voltage levels at terminals A, C

52、, G and S are at no care condition.Step I: Rotating any of the rotary selector switches one step toward clockwise direction will supply 5 volts to the corresponding display, provides a high level voltage at terminals 1, 2 or 3 indicating that one passenger have entered the taxicab. A high level volt

53、age should be applied to terminals A, C or G in order to ensure that the corresponding display is still blanked. Other terminals B, D, H and S are kept unchanged. Step 2: Rotating the rotary selector switch onestep further, will change the state of voltages at terminal A, C or G to be at low level a

54、nd unblanks the corresponding display. States of voltages at terminals I, 2, 3 and S are remained unchanged.Terminals B, D and H should be remained at low level to ensure that the corresponding readout is cleared to zero while unblanking the display.摘要本文提出了一種出租車多通道計價的方案，能同時處理一個以上乘客的情形。為了從理論上說明本方案，提出

55、了一個實驗上的三通道型的士的完整設計其原型是根據埃及科學和技術研究學院的研究而建成得）。1 .導言在不發達的國家，早上把人們從他們家送到工作的地方，然后下午送回來已成為一個大問題，尤其是在大城市。作為解決這個問題的一個部分，在某些國家出租車用來解決這個問題，送人們從一個地方到另外一個地方。例如，出租車的四個席位可攜帶四個不同的沒有任何關系的乘客，除了他們的路線是相同的。因此，依靠目前的傳統的單車道計價以確定所需的票價，把每個乘客的計費分開，這已成為一個非常困難的問題。因此，在出租車司機，車主，乘客和國家稅務部門之間存在著不公平的財政關系。在這種情況下，出租車司機強迫乘客支付多于他們所應付的。在

56、某些情況下乘客支付了他們應付車費的雙倍。本常規單頻道計程車，出租車司機不能夠確定出租車日常收入。在某些情況下 出租車的4個席位），他們可能只有出租車四分之一的收入大部分的出租車司機）。從這些支付工資的出租車司機以及作為燃料費用外，還要維修以及汽車折舊等費用。事實上，出租車業主并非似乎如此糟糕。一項在出租車司機和車主之間的協議已經達成，司機應保證每天固定收入，以及向業主支付燃料以及維修的費用。即使如此，還是有的出租車司機的很大一部分份額之收入的出租車。現在還存在的單聲道計價，已經變得非常，國家稅務部門也知道這種困難每年估計出租車業主的收入支出，以及應支付的稅務也很困難。為了應對這一問題，國家稅務

57、部已實行固定估計稅，每個座位的出租車不論收入。在本文中，我們介紹了多通道的士計程表，可處理超過一名乘客同時進行的情況。我應該指出，我所說的長期旅客指一個人或一組相關的人。我同時也應指出，我們提出的多渠道的計價，不是簡單地說，一個多顯示讀數。作為一個先進的事項，事實上它包含邏輯電路，可以自動計算變化的車費以及每公里行走距離或每分鐘的候車時間按照乘客人數雇用出租車。在下面的部分，我舉出一個例子，我們將介紹一個完整的三通道計價。框圖以及詳細的電路圖，實驗三通道計價功能也包括在內。原型下已建成埃及贈款科學學院和技術研究。2 .實驗THREECHANNEL出租車計價器理論的運作我們的實驗裝置從事電子數字

58、計價依據。事實上速度電纜旋轉1 圈的每 M 距離行駛。因此，如果車速電纜耦合與速度傳感器，產生一個單脈沖每平方M 的旅行距離，那么，我們的的士可以三倍于反模塊相與速度傳感器的單位。然而，我們的實驗是計價而不僅僅是只顯示三個讀數。事實上，它包含邏輯電路，可以根據每公里的行駛距離或每分鐘等候時間按照乘客人數雇用出租車來自動改變車費。該裝置可能會分成兩個主要部分組成：第一是速度傳感器，這個傳感器可位于任何地方，在出租車內進行這樣一個簡單的耦合車速電纜是可以實現的。單位包含了主要的電子電路，顯示器以及控制面板。該單位應位于前排的司機和乘客之間。A速度傳感器其主要職能是本單位提供脈沖的培訓，這個脈沖的頻率會于旋轉角度相適合。一種可能的形式一個速度傳感器。如果可以包含正弦波發生器的輸出連接到脈沖整形電路的永磁器件<2 通用芯片二極管，1000歐姆的電阻和施密特觸發逆變器）。為了找到某種方式來檢測出租車的運動，正弦波發生器的輸出是糾正通過一個通用的硅二極管延胡索乙然后平滑的1000年 F電容。那個輸出電壓在終端Q是當時限于價值4.7伏特用益歐姆的電阻以及一個齊納二極管ZD 。出租車的終端電壓在終端Q 將高電壓降為零。這電壓可作為改變出租車從距離計費到時間