FR2522425A1 - Analogue signal detector for e.g. joystick - has rectangular resistive panel with known time dependent voltages applied to X and Y coordinates - Google Patents

Abstract

The detector uses a thin electrically resistive layer (5) deposited on a flat surface or 'table'. The corners (A,B,C,D) of this table are joints between lengths of resistance wire which is in contact with the resistive film. Voltages are applied to these four points as follows: V(A)=0; V(B)=V1(t); V(C)=V1(t)+V2(t); and V(D)=V2(t). The potential at a particular point having coordinates (x,y) along the two axes (AB,AD) is V(M,t)=(x/AB)V1(t)+(y/AD)V2(t). With suitable synchronous detectors linked both to the derived voltage and the time-varying voltages, voltages V1(t) and V2(t), the x,y coordinate position may be determined.

Description

 The subject of the invention is a device and its method for analog data entry and display of said data.

 Currently, data acquisition tables are of the digital type, for example, diode arrays. It is therefore easy to understand the complexity of the wiring. In addition, the table grid cannot be very precise. These tables are therefore very expensive due to the wiring of the diodes.

 The invention avoids all these drawbacks.

 It makes it possible to manufacture plotters at costs four to five times lower than with the current technique.

 The accuracy of the plotter, according to the invention, is very high. The network can be gridded to 1/1000 mm.

 The invention uses a surface such as a resistive layer and a filtering means such as synchronous detection.

 The device and its analog input method allow the tracking of a point on a plane by associating two voltages Vx (t) and V (t) proportional to the coordinates x (t) and y (t) of said y point at the moment. t or varying linearly with these coordinates x (t) and y (t).

This so-called "analog table" device and its application method are mainly constituted in a preferred version, by a uniform thin resistive layer deposited on a flat surface, of resistance Rt per square. The table or flat surface preferably has a rectangular shape; the angles are noted A,
B, C and D.

Points A and B, B and C, C and D, D and A are joined by a resistive wire, or any other resistive system brought into electrical contact with the resistive film of the table; this resistive wire has resistance
R1 for AB, R2 for BC, R3 for CD and R4 for DA. If this resistive wire is applied along a circular contour, or as a first parabolic approximation, such that the distances from the midpoint of these wires to the segments AB, BC, CD and DA verify the relations: 1 î = R1 / 8Rt, g 62 R2 / 8Rt
The mathematical calculation shows that if the following potentials are applied to points A, B, C and D
* V (A) = 0
* V (B) = V1 (t)
* V (C) = V1 (t) + V2 (t)
* V (D) = V2 (t) where V1 and V2 are arbitrary functions of time.

The potential of a current point M, of coordinates x and related to the axes AB, AD is
* V (M, t) = (x / AB) V1 (t) + (y / AD) V2 (t)
The potentials V1 and V2 are chosen so as to be periodic with frequencies "1 and W 2.

pendant une demi période 2 =O
V

pendant l'autre demi période
Dans une version préférée, le potentiel V(M) subit une détection dite "synchrone" par rapport aux fréquences 1 et 2' ou par rapport aux potentiels appliqués en B et D. Cette détection synchrone fournit deux tensions V et V variant proportionnel
x y lement avec les coordonnées x et Z du point M. En fait, on peut aussi utiliser tout système de filtrage conduisant à la séparation des composantes aux fréquences w 1 et tv2 2 du potentiel V(M,t). In a preferred version, the potentials V1 and V2 are chosen as follows -V1 = 0 -V9 =

for half a period 2 = O
V

during the other half period
In a preferred version, the potential V (M) undergoes a so-called "synchronous" detection with respect to frequencies 1 and 2 'or with respect to the potentials applied at B and D. This synchronous detection provides two voltages V and V varying proportional
xyly with the x and Z coordinates of point M. In fact, one can also use any filtering system leading to the separation of the components at frequencies w 1 and tv2 2 of the potential V (M, t).

 The data visualization device and method provide a permanent visual image of a plot made on a data entry table (for example, the analog table described above).

 The data entry device provides information in the form of voltages V (t) and V (t).

xy
The invention makes it possible to store this data on a closed magnetic medium rotating at low speed, then to restore this data by rotating this closed medium at a frequency of the order of 15 Hz (cinema frequencies).

 Any known operating device associated with the device according to the invention then allows viewing of the initial route.

We can cite, for example, an oscilloscope screen, an advertising screen ...

 The closed magnetic support can be constituted by a closed magnetic strip, or in a preferred version, by a flexible magnetic disc or not (for example the conventional discs used in computer science).

 In a preferred version of the invention, the data relating to the x and y coordinates are recorded on two different tracks using a double magnetic head or two separate heads.

 Still in a preferred version, a coding system is used which eliminates the inhomogeneities of the band. The simplest coding system is conventional and consists of a series of pulses, the distance of which depends on the amplitude of the signal to be coded.

 The decoding of this type of pulse is well known and will not be described here.

 In a preferred version of the invention, when the device for capturing the potential of the analog table (metallic or conductive tip) is raised, that is to say when the signal to be coded no longer arrives, a device basic electronics to be made allows the recording system to be stopped.

 Still in a preferred version, an elementary electronic device accumulates the recording times and stops this recording after one turn of the tape or of the magnetic medium.

 These devices are conventional, in the public domain and are not described here.

 The attached drawings will easily make it possible to understand the invention. They represent a preferred embodiment according to the invention.

 FIG. 1 is a schematic view of a plotter with synchronous detection using a uniform thin resistive layer deposited on a flat surface of resistance Rt per square.

 Figure 2 is an electronic diagram and a flow diagram of the functions.

 FIG. 3 is a view of the implementation of the method according to the invention, which makes it possible to combine a positioning joystick commonly known as "Joy Stick", or broom stick positioner and a resistive table.

 Figure 4 is a diagram which allows, according to the method to position in volume.

 In Figure 1, the four points A, B, C, D are arranged at the four corners.

If the following potentials are applied to points A, B, C and D
ir V (A! = O
* V (B) = V1 (t)
* V (C) = V1 (t) = V2 (t)
* V (D) = V2 (t) the potential of a current point M, of coordinates x and y related to the axes AB, AD is
* V (M, t) = (x / AB) V1 (t) + (y / AD) V2 (t)
In a preferred version, the potential V (M) undergoes a so-called "synchronous" detection with respect to the frequencies w 1 and # 2 or with respect to the potentials applied at B and D. This synchronous detection provides two voltages V and V varying proportional
xyly with the x and y coordinates of point M. In fact, one can also use any filtering system leading to the separation of the components at frequencies W 1 and w 2 of the potential V (M, t).

 A resistive film deposited on said table 2 in which, in a preferred version, the device for applying the potential is produced by means of a resistive linear element brought into contact with the table 2. Said film is a graphite placed on an insulating support .

The resistivity can be, depending on the applications, of the order of 2000 ohms per square. This product is a resist film produced by the company SFERNICE in Nice, in France.

 According to a variant, the resistive element 5 is arranged along a parabolic or circular contour for each segment such that the apex of the parabola (or of the circle) is at a distance s from the segment considered such that g = Rf / (8R), where R is the resistance per square of the resistive film covering the table and Rf the total resistance of the resistive excitation element.

The tensions applied to the vertices A, B, C and D of the rectangle constituting the table are such that
* V = V
o
* VBV + V1 (t)
o
* VV + C V1 (t) + V2 (t)
* VV + * VD = VO + V2 (t).

 A device combined with the table is combined with a means acting as a filter 4 and 6 around the frequencies 1 and 2 intended to obtain voltages varying independently with the coordinates of a point on the table whose potential is analyzed. The filtering means is constituted by a synchronous detection.

 FIG. 2 represents the electronic diagram of the device and the flow diagram of the functions.

 The resistive table 2 coated with its uniform thin resistive layer is electrically connected to its four corners A, B, C D.

These points A, B, C, D are connected to an oscillator 7 or clock x and to an oscillator 8 or clock, each corresponding to the coordinates Xl of a point on the table 2. These oscillators are connected to each other possibly by means synchronization and phase shift 9. In parallel, connected to one of the corners of the table 2, an adder 10 is connected.

 The information collected goes to two logical gates 11 and 12; filtering and shaping means 4 and 6 make it possible to obtain the signals x and ~ which can be reproduced for example on an oscilloscope, not shown.

Finally, in FIG. 3, a positioning lever 13 is mounted on cardan shafts or a ball joint suspension 14, on a resistive table 2. The tip 15 of this positioning lever or "Joy Stick" comprises a support spring, not shown, which comes into contact with the resistive layer 5. The outer box 16 is shown in dotted lines. The outputs and inputs 17 correspond to the power supply and to the outputs of the signals x and
We can easily understand the advantage of this application which currently exists by using, at the level of the cardan or ball joints, at least two potentiometers with a set of gears. This mechanism is expensive to manufacture, assemble and moreover is not reliable.

 On the other hand, the invention lowers the cost of this application since there is no mechanics, and makes it possible to obtain a very fine positioning with this lever 13.

In Figure 4, three oscillators or clocks are necessary. We consider the cube A, B, C, D, A ', B', C ', D' and the signals S1, SQ 53 of the oscillators. The signals to be applied are
3 shown diagrammatically in FIG. 2.

A: OA ': S3
B: S1 B ': S1 + S3
C: S1 + S2 C ': S1 + S2 +
D: S2 D ': S2 +
The signal collected at a point in the fluid will be xS1 + YS2 + zS3, the coordinates x, y, z, being obtained by synchronous detection and filtering described above.

Claims (14)

 1. A method of analog data entry and visualization of said data characterized in that one uses, as means acting as data acquisition table, a thin resistive layer (5) uniform deposited on a flat surface called table (2), the angles A, B, C and D are joined by a resistive wire brought into electrical contact with the resistive film of said table (2), if the potentials are applied to points A, B, C, D following: * V (A) = 0  * V (B) = V1 (t)  * V (C) = V1 (t) + V2 (t)  * V (D) + V2 (t) the potential of a current point M, of x and y coordinates related to the axes AB, AD is  * V (M, t) = (x / AB) V1 (t) + (y / AD) V2 (t)  2. A method of analog data entry and display of said data according to claim 1 characterized in that the potential V (M) undergoes a so-called "synchronous" detection with respect to the potentials applied in B and D, this synchronous detection provides two voltages Vx and V which vary proportion  x y n ally with the x and r coordinates of point M.  3. A method of analog data entry and display of said data according to any one of claims 1 or 2 characterized in that the data are stored on a closed magnetic medium rotating at low speed, then restored by rotating said closed medium at a frequency of the order of 15 Hz.  4. A method of analog data entry and display of said data according to any one of claims 1, 2 or 3 characterized in that the data V and V are  x y used to allow visualization of the initial trace on an oscilloscope screen.  5. A method of analog data entry and display of said data according to any one of claims 1, 2, 3 or 4 characterized in that the data relating to the coordinates x and y are recorded on two different tracks by means of a double magnetic head or two separate heads.  6. A method of analog data entry and visualization of said data according to any one of claims 1, 2, 3, 4 or 5 characterized by the fact that the filtering means is constituted by synchronous detection.  7. A method of analog data entry and display of said data according to any one of claims 1, 2, 3, 4, 5 or 6 characterized in that the tip (15) of a positioning handle (3) mounted on cardan shafts or a suspension with ball joints (14) comes into contact, by means of a spring-acting means, on the table (2) coated with a resistive layer.  8. A method of analog data capture and display of said data according to any one of claims 1, 2, 3, 4, 5, 6 or 7 characterized in that to obtain the volume positioning, three oscillators or clocks are used (S1, S2 'S3).  9. Device for implementing the method according to any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 characterized in that it consists of a thin resistive layer (5) uniform deposited on a flat surface called table (2), to which periodic voltages of several frequencies are applied by another external device associated with a device for detecting (3) the potential of a point on the table (2).  10. Device for implementing the method according to claim 9 characterized in that the application of the potential is achieved by means of a resistive element brought into contact with the table (2).  11. Device for implementing the method according to any one of claims 9 or 10 characterized in that the resistive element (5) is arranged in a parabolic or circular contour for each segment such as the top of the parabola (or the circle) is at a distance (;) from the segment considered such that (wf) = Rf / (8R), where R is the resistance per square of the resistive film covering the table and Rf the total resistance of the resistive element of excitement.  12. Device using data acquisition according to the method according to any one of claims 1, 2, 3, 4, 5, 6, 7 or 8.  13. Positioning handle or positioner joystick (13i according to any one of claims 9, 10, 11 or 12 characterized in that it is mounted on cardan shafts or a  ball joint suspension (14) on a resistive table (2), the tip (15) of this positioning lever or "Joy Stick" includes a spring  support, not shown, which comes into contact with the layer  resistive (5); the outer box (16) is shown in  dotted; outputs and inputs (17) correspond to aiimenta  tion and at the x and x signal outputs  14. Analog data entry and visualization process  tion of said data according to claim 1 characterized by  used as a means to act as an acquisition table  sition of data a thin resistive layer (5) uniform deposited  on a flat surface called table (2), the angles A, B, C and D are  joined by a resistive wire brought into electrical contact with the film  resistive of said table (2), the potentials V1, V2 are chosen from  the following way - V1 = O -V, =

 for half a period - v - o - V1 V

 during the other half period.