SPECIFICATIONMeasuring calculatorThis invention relates to electronic devices of the kind commonly called calculators and in particular to pocket calculators.
According to one aspect of the present invention there is provided an electronic calculator, incorporating a transducer responsive to a physical quantity and connected to the calculator processing and display means whereby the calculator is operable as a measuring device for the said quantity.
According to another aspect of the present invention there is provided an electronic calculator comprising in combination, as a single unit, a LSI microprocessor, a keyboard and a display connected thereto, and a transducer responsive to a physical quantity, the transducer being connected to the microprocessor, and the latter being designed and/or programmed to perform calculator functions in conjunction with the keyboard and display and to process the signals provided by the transducer and to display the results of such processing.
The transducer can for example be a wheel or other distance measurer and in this case the processor is preferably set up so as to calculate areas or volumes from the measured distances.
In another embodiment the transducer is a temperature sensor. Preferably, means are provided for additionally connecting an external temperature sensor, for convenience of measurement.
In a further embodiment, the transducer is sensitive to light. In this case, the processor is arranged so that the calculator can function also as a photographic light meter.
In a further embodiment the transducer is a weight sensor. This embodiment will usually be a desk or table top calculator rather than a pocket calculator, and in a preferred arrangement the processor is arranged to calculate postal charges of the articles weighed, on the basis of programmed postal rates.
The processor may be a common chip designed to perform all the above-mentioned functions, selection of particular functions being effected by particular external connections of the processing chip.
Thus, a common chip can be used in calculators having different types of transducer.
Embodiments of the invention are illustrated by the accompanying drawings, in which:Figures 1 and 2 are top and end views of a calculator incorporating a distance measurer,Figures 3 to 5 are plan, side and end views of a calculator with internal and external temperature sensors,Figures 6 and 7 are plan and end views of a combined calculator and photographic exposure meter,Figures 8 and 9 are plan and side views of a combined calculator and postal scales,Figure 10 is a block diagram of a calculator with a transducer, andFigure 1 1 is a simplified flow chart of one form of processor.
Figures 1 and 2 show a pocket calculator with a casing 1 of suitable size, provided with a keyboard 2 and a display window 3. In addition to conventional data entry keys, arithmetic operation keys and command keys, the keyboard includes a selector switch 4 and keys for ENTER, RESET,RECALL, AREA and VOLUME. These are associated with five data registers and processing circuitry in the calculator chip, and a distance measuring wheel 5 which projects from one corner of the casing and drives a suitable transducer so as to produce electrical signals in proportion to the revolutions of the wheel.
With the selector switch set to "cal", normal calculator functions are obtained through the use of the keyboard. With the selector switch set to "dimension", the calculator can be used to measure distances, by rolling the wheel 5 along a line or object to be measured. The measured distance can be temporarily stored, processed in order to calculate the area of a measured figure or the volume of a measured object, and displayed. More specifically, the following functions are provided:RESET Pressed, event counter and display are reset to zero.
ENTER Pressed, store the distance displayed into one of the five (5) data registers indicated by adata register pointer. Increment data register pointer.
RECALL Pressed, recall data from the data register indicated by the data register pointer, displaydata and increment data register point. If pointer is pointing at the fifth register, whenpressed, pointer will be set to first data register.
M+ M- Pressed, add or subtract the displayed number into or from the memory registerrespectively.
Mcr Pressed, recall data of the memory register to the display register.
Successive depressons will clear the memory register.
AREA Pressed, calculate area from measured distances according to equations below theequation used depending on the position of the data register pointer. Store result atarea register.
Set status bit to '1'.
VOLUME Pressed, calculate volume from measured distances according to equations below, theequation used depending on the position of the data register pointer and status bit.
CE/C Pressed, clear all registers and set pointer to position 1. Set status bit to 'O'.
pointer pos. equationArea Triangle 4 st (O) v's(s-a) (s-b) (s-c), s=-(a+b+c) Square 3 st (O) a2Rectangle 3 st (O) (a) (b)Circle 2 st (0) (p2)/(47)Volume Cube 4 st (O) a3Parallelogram 4 set (O) (a) (b) (c)Sphere 2 st (O) (p3)/(6X2) Circ Cylinder 3 st (1) (area of circle) (h)Tri. Prism 5 st (1) (area of triangle) (h) a, b, c = length of sides p = circumference h = lengthThus to measure and display a length the operations are:Reset (R) - measure - enter (E).
To measure areas the key sequences are: Square: R+measure sideEEkey AREA (A) Rectangle: Rmeasure side a#E#R#measure side b#E#A Circle: Rmeasure circumference#E#A Triangle: Rmeasure side a#E#R#measure side b#E#R#measure side c#E#A The keying sequences for measuring volumes are:Cube: R#measure side#E#E#E#key volume (v)Cuboid: R#measure side a#E#R#measure side b#E#R#measure side c#E#V Sphere:: Rmeasure circumference#E#V Prism: Rmeasure side a#E#R#measure side b#E#R#measure side c#E#A#R#measure side c#E#A#R#measurelength#E#V Cyl: R#measure circumference#E#A#R#measure length#E#V As the measuring wheel can produce outputs in the form of pulses, the transducer output can be connected substantially directly to an event counter of the processing circuitry, operating for example at one centimetre per pulse, or at a greater frequency for more accurate measurement.
Figures 3 to 5 show another pocket calculator, which has an internal temperature sensor 6 and a socket 7 for connection of an external temperature sensor 10 by means of a flexible conductor 9 and a plug 8. The standard calculator keyboard is supplemented by a selector switch for "calculator" or "temperature" and buttons for RECALL, ENTER, F and OC. Connection of the external sensor automatically disconnects the internal sensor.The sensors are of any convenient type, sensitive for example minus 500 to 1500 C. The sensors are connected to the processing circuitry through a voltage-frequency converting interface with a frequency range of for example 4 kHz to 8 kHz, and the processing circuitry includes a frequency counter operating at 20 Hz per OC. Temperature can be displayed in C or OF. A displayed temperature, either measured or entered through the keyboard, can be converted from OF to C or vice versa, by operation of the corresponding temperature scale key.
With the selector switch set "Calculator" the usual calculator functions are available. With the selector switch set to "temperature", temperature is measured by placing the internal or external temperature sensor on the object or in the area of which the temperature is to be measured, and pressing the ENTER key. Five temperature data registers are provided so that five temperatures can be stored. Key operation is as follows:ENTER Pressed, store temperature displayed into one of the five (5) data registers indicated by thedata register pointer.
Increment data register pointer.
RECALL Pressed, recall data from the data register indicated by the data register pointed, displaydata and increment data register pointer. If the position of the pointer is at the fifth dataregister, pointer is set to point at the first register.
F 1. during measurement, when pressed, display in F2. during conversion, pressed before key-in data indicate key-in data is F.
3. during conversion, pressed after key-in data indicate key-in data is to be converted to OF.
C similar to the 0F key, except all OF replaced by OC.
CE/C - clear all registers and set data register pointer to position 1.
The calculator shown in Figures 6 and 7 has, in addition to its calculator keyboard 2 and display 3, a built-in light sensor behind a diffuser window 12 at one end of the calculator casing. The light sensor is connected through a voltage-frequency converter to a frequency counter of the processing circuitry which is programmed to convert the measured voltage/frequency into light intensity according to a suitable characteristic equation.
The keyboard has a selector switch 1 3 to select calculator or light meter operation, a peak detection selector switch 14, and additional keys as follows:ENTER Pressed, store key-in value into the relevant register. They are A.S.A., aperture andshutter. Or store measured lux value into lux register.
A.S.A. Pressed to indicate the following key-in data is the reciprocal of shutter speed.
APERTURE Pressed to indicate the following key-in data is the aperture value.
(note: new entered data will write over the contents of the register).
To enter data, press the data-identifying key, enter the value using the keyboard, and press theENTER key.
In use: (1) Switch "Cal/lux" key 13 to "lux" position.
(2) For peak detection, lock peak switch 14 to 'on' position unit to record peak reading displayed.
(3) For normal operation, position meter and take reading from display.
(4) Press ENTER key to store instantaneous reading.
(5) Enter shutter speed and press Aperture to display aperture value, or (6) Enter aperture value and press Shutter to display shutter speed.
The PEAK setting is for use with flash: the flash is triggered, the display shows the peak light value, and this can be stored by pressing ENTER.
The display is controlled to include indicators showing whether the displayed value is film speed, aperture, shutter or light intensity, and may include a "LOW" warning for either shutter speed or aperture value.
Facilities for measurement and display using DIN film speed units may be included.
The three calculators described above are all small pocket calculators, using primary or secondary batteries and preferably having LCD displays to conserve power.
Figures 8 and 9 show a desk calculator (which accordingly can have a connector for an AC supply adaptor, and a LED display or printer if desired), incorporating a letter-weighing device. The latter comprises a platform 15 at the rear of the calculator casing, operating any suitable electrical or electromechanical load sensor which is connected to the calculator processing circuitry through a voltagefrequency interface driving a frequency counter, operating at for example 8Hz/grm over a frequency range four kHz to eight kHz, corresponding to a weighing range of O to 500 grms.
A zero-setting control 16 is provided for the weighing platform.
The illustrated device is designed to have a general appearance similar to a conventional desk top calculator. Alternatively, the device can be designed as a decorative object.
The calculator has a conventional keyboard supplemented by keys to select local and foreign and postal rates, and selector switches for selecting operation as a calculator or as a weighing device, and for selecting a programming mode enabling the user to enter into respective registers the postal charge rates corresponding to different weights for foreign and local mail.
Postal Rate Programming (1) Switch program switch 17 to 'ON' (2) Enter postal rates for each of the available zones by pressing FOREIGN and N or LOCAL and N keys.
(NOTE: N is the numerical key(s).) (3) Number of memories available is 6.
Weighing ( 1 ) Switch 'Cal/Weight' Switch 18 to 'Weight' position.
(2) Place object on scale, weight is displayed.
(3) Select postal rate by either pressing FOREIGN and N keys or LOCAL and N keys.
(4) Data displayed is the actual postal charge.
The display will show the actual value, whether the foreign or local rate is applicable, and whetherthe object is overweight.
Dedicated chips incorporating the necessary interface and counter circuitry as well as the processing and control circuitry can be provided for each of the calculators described. The hardware for each calculator is generally as shown in Figure 10, comprising the keyboard 2, display 3 (for example an eight-digit LCD), a micro computer 19 with suitable counting and register circuits, the appropriate transducer 20 and interface 21 if required between the transducer and the micro computer. The transducer senses the parameter to be measured and provides a voltage output representing, and preferably proportional to, the value of the parameter. The interface (not essential for the distance measurer) converts voltage to frequency, providing a signal which the micro computer can process in digital fashion using its counting circuitry.
We envisage that programs for all of the four functions described (distance measurement, temperature measurement, light measurement and weighing) together with the calculator program will be provided on a single LSI chip, the selection of the program required for any particular calculator device being by suitable external connection of the chip. Figure 1 1 shows a simplified flow chart for a common LSI chip of this nature. The flow chart is self-explanatory and is therefore not further described.