CN115756218A - Two-dimensional plane coordinate rapid digital input system and implementation method - Google Patents
Two-dimensional plane coordinate rapid digital input system and implementation method Download PDFInfo
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- CN115756218A CN115756218A CN202211446670.7A CN202211446670A CN115756218A CN 115756218 A CN115756218 A CN 115756218A CN 202211446670 A CN202211446670 A CN 202211446670A CN 115756218 A CN115756218 A CN 115756218A
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Abstract
The invention relates to the technical field of computer peripheral digital two-dimensional coordinate input, in particular to a two-dimensional plane coordinate rapid digital input system and a realization method thereof, wherein the system comprises an electromagnetic pen and a handwriting input device, the handwriting input device is provided with an input system, the input system comprises a main processing MCU chip, a receiving circuit, an output circuit and X, Y array antenna units, a clock signal generating unit and a clock signal output pin are arranged in the main processing MCU chip, and the receiving circuit is provided with a phase discriminator; the output circuit is provided with a signal matching amplification unit and a three-state gate, X and Y antennas are used for transmitting simultaneously, the main processing MCU chip is provided with at least two paths of ADCs of hardware, the ADCs are respectively used for receiving X and Y antenna echo signals simultaneously and calculating the coordinate value and the inclination angle of the electromagnetic pen in a two-dimensional coordinate plane, and the pressure change of the pen is obtained in real time by integrating the phase difference of the hardware and sampling calculation of the main processing MCU chip by adopting the principle of a phase discriminator.
Description
Technical Field
The invention relates to the technical field of computer peripheral digital two-dimensional coordinate input, in particular to a two-dimensional plane coordinate rapid digital input system and an implementation method thereof.
Background
With the rapid development of computer technology, peripheral coordinate input devices and systems for computers have also been developed rapidly. Especially, the input requirement of the digital coordinate system in the fields of writing, drawing, signing, two-dimensional plane coordinate input games and the like is stronger, and the requirement on the real-time accuracy of the coordinate input is higher and higher. The input modes of handwriting input devices such as electromagnetic boards and electromagnetic screens include electromagnetic induction type and thin film resistors, and the electromagnetic induction type is mainly used in combination with a special electromagnetic pen.
The principle of a system consisting of a passive electromagnetic induction pen and an electromagnetic plate or an electromagnetic screen is that the electromagnetic plate or the electromagnetic screen respectively transmits electromagnetic waves in a plurality of metal coils arranged in the X and Y directions one by one and receives echo signals of the electromagnetic pen positioned in an induction area, so that the position of the electromagnetic pen positioned on the surface of the electromagnetic plate or the electromagnetic screen is obtained through the signal intensity difference calculation of adjacent antennas.
The system principle of the active electromagnetic pen and the electromagnetic plate or the electromagnetic screen is that the electromagnetic pen actively emits electromagnetic waves, a plurality of coils arranged in the X and Y directions of the electromagnetic plate and the electromagnetic screen are used for respectively scanning the X and Y directions one by one to obtain signals emitted by the electromagnetic pen, and the position and the inclination angle of the electromagnetic pen on the surface of the electromagnetic plate or the electromagnetic screen are obtained through calculating the voltage difference of adjacent antennas;
the present invention discloses another object of designing a wireless pointer device (pen, mouse, positioning disc, etc.) in cooperation with the electromagnetic induction antenna loop arrangement design method, including using a resonant circuit formed by a variable inductor and a capacitor to induce and receive electromagnetic energy, storing the energy by resonance and then transmitting the energy back to the digital board, so as to achieve the effect of providing a power supply for the wireless pointer device. Because the pointer device of the invention will cause different frequency changes (one is increasing the frequency, the other is decreasing the frequency) when the pen point presses the digital board and presses the key, the invention not only can more easily judge the operation of the pointer device by the user, the probability of misjudgment is reduced, but also has relatively lower requirement on the precision of the frequency induction detection, so the circuit design is relatively simple, and the cost can be further reduced. Moreover, the variable inductor is linked with the pen point of the pointer equipment, so that the variable quantity of the frequency generated when the pen point is pressed is larger, the invention can directly judge the pressing pressure of the pen point by sensing the variable quantity of the frequency, the circuit design required to be used is relatively simple, the precision sensing technology is not required, and the cost is relatively lower. "
The two modes are realized by adopting a mode of firstly scanning the X or Y direction and then scanning the antenna coil in the Y or X direction when receiving the signal of the electromagnetic pen. The mode is similar to a progressive scanning mode of a traditional CRT television, scanning efficiency is low, the sampling of echoes at any position has the sequence of X and Y directions, and a pen moves in real time during sampling, so that a coordinate value calculated by using an ADC (analog to digital converter) value of actual sampling can have a certain difference with a theoretical value, and particularly under the condition that an electromagnetic pen moves rapidly, the phenomenon is more obvious, and the phenomenon of smear formed by delaying similar shooting and photographing is formed.
For electromagnetic pens, the mainstream solutions in the market today are analog pens (active (with battery capable of actively emitting electromagnetic waves), passive (passively generating electromagnetic resonance)), and digital pens. The mode of simulating the pen to calculate the pen pressure is mostly to change the value of inductance or capacitance on the pen, so that the resonance frequency changes, and the electromagnetic plate or the electromagnetic screen judges the change of the frequency through a software algorithm to convert the change into the pressure value. The digital pen is characterized in that a pressure sensing device on the pen is changed, sampling is carried out through an ADC on the pen, the MCU calculates and feeds back the pressure sensing device to the electromagnetic plate or the electromagnetic screen in a digital modulation mode, and the two modes require long time.
In order to solve the problems, the invention adopts X and Y antennas to transmit simultaneously, and the main processing chip MCU is provided with at least two paths of hardware ADCs which are respectively used for simultaneously receiving X and Y antenna echo signals and calculating the coordinate value and the inclination angle of the electromagnetic pen in a two-dimensional coordinate plane. For the calculation of the pen pressure, the invention adopts the principle of a phase discriminator, obtains the pressure change of the pen in real time by integrating the phase difference of hardware and sampling calculation by a main processing chip MCU, and finally outputs data such as coordinates, inclination angles, pressure and the like through interfaces such as USB, UART, I2C, SPI and the like of the main processing chip MCU, thereby providing a two-dimensional plane coordinate rapid digital input system and a realization method.
Disclosure of Invention
The invention provides a two-dimensional plane coordinate rapid digital input system and a realization method for overcoming the defects of the above situation, and the technical scheme is as follows.
A two-dimensional plane coordinate fast digital input system comprises an electromagnetic pen and a handwriting input device, wherein the handwriting input device is provided with an input system, the input system comprises a main processing MCU chip, a receiving circuit, an output circuit and an X and Y array antenna unit, a clock signal generating unit and a clock signal output pin are arranged in the main processing MCU chip, the receiving circuit is provided with a phase discriminator, the output circuit is provided with a signal matching amplifying unit and a tri-state gate, the clock signal generating unit is used for generating a clock signal by the generating unit, the clock signal output pin is used for outputting the clock signal, the signal matching amplifying unit is used for amplifying and differentiating the clock signal, the tri-state gate is used for outputting the differentiated clock signal to the X and Y array antenna units, the X and Y array antenna units are used for receiving an echo signal of the electromagnetic pen and amplifying and filtering through an X and a Y path, two paths of ADC modules are arranged in the main processing MCU chip, and the ADC modules are used for inputting the received and filtered signal to the main processing MCU chip through an ADC input end and carrying out analog-to-digital conversion on the echo signal. The phase discriminator is used for obtaining the pressure change of the electromagnetic pen in real time through hardware phase difference integration and ADC sampling calculation in the main processing MCU chip.
Further, the clock signal generating unit is a PWM module, and the PWM module is configured to generate a square wave clock signal.
Furthermore, the clock signal output pin is a GPIO pin, and the GPIO pin is used to output a square wave clock signal.
A method for realizing a two-dimensional plane coordinate rapid digital input system comprises the following steps:
step 1, firstly, generating a square wave clock signal S0 with a certain frequency by a PWM module of a main processing MCU chip and outputting the square wave clock signal S0 by a GPIO pin;
step 2, amplifying and differentiating the square wave clock signal S0 output by the GPIO pin by the main processing MCU chip to generate positive and negative sharp waves S1 and S2 with larger amplitude;
step 3, selecting a control unit, an X1.. Xn analog switch array and a Y1.. Yn analog switch array by the sharp waves S1 and S2 through an X path and a Y path, and simultaneously outputting the signals to an XY array antenna unit, wherein the sequence and the number of the switches of the X1.. Xn analog switch array and the switches of the Y1.. Yn analog switch array can be dynamically adjusted according to actual conditions in the subsequent operation process;
step 4, in the process of transmitting signals by the main processing MCU chip, if an electromagnetic pen exists in the antenna radiation area, the electromagnetic pen can receive signals S1 and S2 sent by XY antennas of the XY array antenna unit, and the electromagnetic pen can generate oscillation signals S3 and S4 ；
Step 5, after the main processing MCU chip finishes signal transmission, simultaneously converting an X1.. Xn analog switch array and a Y1.. Yn analog switch array switch into a receiving mode through a three-state gate, and opening an operational amplifier part of a receiving circuit, wherein in a T1.. Tn time period in an S5 waveform opened by the operational amplifier, an XY array antenna unit simultaneously amplifies, filters, shapes and integrates received signals through X and Y channels to obtain echo signals S6 and S7;
step 6, sampling the X and Y antenna echo integral signals S6 and S7 by two ADC of the main processing MCU chip hardware, ensuring the synchronism of any one coordinate point in X and Y sampling, and calculating the position and the inclination angle of the electromagnetic pen in a two-dimensional plane coordinate through the voltage difference of adjacent antennas;
step 7, because the pen pressure change of the electromagnetic pen is that the value of the capacitance device or the inductance device is changed, so that the frequency of the electromagnetic wave is slightly changed, according to the principle of the phase discriminator, a certain voltage difference is generated after passing through the phase discriminator, a certain amount of integration is carried out on the voltage difference, and the voltage value obtained after the integration of the phase discriminator can be converted into the pressure value of the pen by referring to the maximum change value of the pressure corresponding to the frequency designed by the electromagnetic pen;
and step 8, outputting data such as coordinates, inclination angles, pressure and the like through interfaces such as USB, UART, I2C, SPI and the like of the main processing MCU chip.
Compared with the prior art, the invention has the beneficial effects that:
the invention adopts X and Y antennas to transmit simultaneously, and the main processing MCU chip is provided with at least two paths of hardware ADCs which are respectively used for receiving X and Y antenna echo signals simultaneously and calculating the coordinate value and the inclination angle of the electromagnetic pen in a two-dimensional coordinate plane.
Drawings
Fig. 1 is a schematic diagram of a module structure according to the present invention.
FIG. 2 is a flow chart of the steps of the present invention.
FIG. 3 is a schematic diagram of waveforms in the present invention.
Fig. 4 is a waveform diagram of the variation of the present invention.
Fig. 5 is another waveform diagram of the present invention.
FIG. 6 is a schematic diagram of the voltage difference according to the present invention.
Detailed Description
As shown in fig. 1-6, a two-dimensional plane coordinate fast digital input system includes an electromagnetic pen and a handwriting input device, the handwriting input device is provided with an input system, the input system includes a main processing MCU chip, a receiving circuit, an output circuit and an X, Y array antenna unit, a clock signal generating unit and a clock signal output pin are arranged in the main processing MCU chip, the receiving circuit is provided with a phase discriminator, the output circuit is provided with a signal matching amplifying unit and a tri-state gate, the clock signal generating unit is used for generating a clock signal, the clock signal output pin is used for outputting the clock signal, the signal matching amplifying unit is used for amplifying and differentiating the clock signal, the tri-state gate is used for outputting the differentiated clock signal to the X, Y array antenna unit, the X, Y array antenna unit is used for receiving an echo signal of the electromagnetic pen and amplifying and filtering the echo signal through an X and Y path, two ADC modules are arranged in the main processing MCU chip, the ADC module is used for inputting the received filtered signal to the main processing MCU chip through an ADC input end to the main processing MCU chip and performing analog-to-digital conversion on the signal, and the echo discriminator is used for obtaining a pressure change of the electromagnetic pen in real-time through hardware phase difference integration and sampling calculation by the main processing MCU chip.
Further, the clock signal generating unit is a PWM module, and the PWM module is configured to generate a square wave clock signal.
Furthermore, the clock signal output pin is a GPIO pin, and the GPIO pin is used to output a square wave clock signal.
A method for realizing a two-dimensional plane coordinate rapid digital input system comprises the following steps:
step 1, firstly, generating a square wave clock signal S0 with a certain frequency by a PWM module of a main processing MCU chip and outputting the square wave clock signal S0 by a GPIO pin;
step 2, the main processing MCU chip amplifies and differentiates the square wave clock signal S0 output by the GPIO pin to generate positive and negative sharp waves S1 and S2 with larger amplitude;
step 3, selecting a control unit, an X1.. Xn analog switch array and a Y1.. Yn analog switch array by the sharp waves S1 and S2 through an X path and a Y path, and simultaneously outputting the signals to an XY array antenna unit, wherein the sequence and the number of the switches of the X1.. Xn analog switch array and the switches of the Y1.. Yn analog switch array can be dynamically adjusted according to actual conditions in the subsequent operation process;
step 4, in the process of transmitting signals by the main processing MCU chip, if an electromagnetic pen exists in the antenna radiation area, the electromagnetic pen can receive signals S1 and S2 sent by XY antennas of the XY array antenna unit, and the electromagnetic pen can generate oscillation signals S3 and S4 ；
Step 5, after the main processing MCU chip finishes signal transmission, simultaneously converting an X1.. Xn analog switch array and a Y1.. Yn analog switch array switch into a receiving mode through a three-state gate, and opening an operational amplifier part of a receiving circuit, wherein in a T1.. Tn time period in an S5 waveform opened by the operational amplifier, an XY array antenna unit simultaneously amplifies, filters, shapes and integrates received signals through X and Y channels to obtain echo signals S6 and S7; since the electromagnetic pen is in the antenna sensing area, the signal intensities of the left and right sides of the central antenna with the strongest sensing signal change with the inclination of the electromagnetic pen, so that the inclination angle of the electromagnetic pen can be calculated by taking the proportion of the difference Δ 3 between the sensing intensities of the left and right antennas to the main wave P0 (as shown in fig. 4);
step 6, sampling the X and Y antenna echo integral signals S6 and S7 by two ADC of the main processing MCU chip hardware, ensuring the synchronism of any one coordinate point in X and Y sampling, and calculating the position and the inclination angle of the electromagnetic pen in a two-dimensional plane coordinate through the voltage difference of adjacent antennas;
step 7, because the pen pressure change of the electromagnetic pen is realized by changing the value of a capacitance device or an inductance device, the frequency of the electromagnetic wave is slightly changed, a certain voltage difference is generated after passing through a phase discriminator according to the principle of the phase discriminator, a certain amount of integration is carried out on the voltage difference, and the voltage value obtained after the integration of the phase discriminator can be converted into the pressure value of the pen by referring to the maximum change value of the pressure corresponding to the frequency designed by the electromagnetic pen; according to the principle of a phase detector (as shown in fig. 5), P0 is an original waveform, P1 and P2 are waveforms after frequency changes, and delta 1 and delta 2 are phase differences. Therefore, a phase discriminator component in the receiving circuit can take a fixed clock signal (S0 in fig. 2) transmitted to the antenna by the main processing chip MCU as a reference source, and compare the reference source with the echo signal of the pen received by the antenna after shaping, if the two signals have different frequencies, a certain voltage difference (as shown in fig. 6) can be generated after passing through the phase discriminator;
and 8, finally, outputting data such as coordinates, inclination angles, pressure and the like through interfaces such as USB, UART, I2C, SPI and the like of the main processing MCU chip.
Various other modifications and alterations of the disclosed structure and principles of the invention will become apparent to those skilled in the art from this disclosure, and all such modifications and alterations are intended to be within the scope of the invention.
Claims (4)
1. A two-dimensional plane coordinate rapid digital input system is characterized in that: the handwriting input device is provided with an input system, the input system comprises a main processing MCU chip, a receiving circuit, an output circuit and an X, a Y array antenna unit, a clock signal generating unit and a clock signal output pin are arranged in the main processing MCU chip, the receiving circuit is provided with a phase discriminator, the output circuit is provided with a signal matching amplifying unit and a tri-state gate, the clock signal generating unit is used for generating a clock signal, the clock signal output pin is used for outputting the clock signal, the signal matching amplifying unit is used for amplifying and differentiating the clock signal, the tri-state gate is used for outputting the differentiated clock signal to the X, the Y array antenna unit is used for receiving an echo signal of the electromagnetic pen and passing the X, a Y path is used for amplifying and filtering, two paths of ADC modules are arranged in the main processing MCU chip, the ADC module is used for inputting the received and filtered signal to the main processing MCU chip through an ADC input end and performing analog-to-digital conversion on the echo signal, and the phase discriminator is used for obtaining the pressure change of the electromagnetic pen in real time through hardware phase difference integration and sampling calculation in the main processing MCU chip.
2. A two-dimensional plane coordinate fast digital input system as claimed in claim 1, wherein: the clock signal generating unit is a PWM module, and the PWM module is used for generating square wave clock signals.
3. A two-dimensional plane coordinate fast digital input system as claimed in claim 2, wherein: the clock signal output pin is a GPIO pin which is used for outputting square wave clock signals.
4. A method for implementing a two-dimensional planar coordinate fast digital input system as claimed in any one of claims 1 to 3, comprising the steps of:
step 1, firstly, generating a square wave clock signal S0 with a certain frequency by a PWM module of a main processing MCU chip and outputting the square wave clock signal S0 by a GPIO pin;
step 2, amplifying and differentiating the square wave clock signal S0 output by the GPIO pin by the main processing MCU chip to generate positive and negative sharp waves S1 and S2 with larger amplitude;
step 3, selecting a control unit, an X1.. Xn analog switch array and a Y1.. Yn analog switch array by the sharp waves S1 and S2 through an X path and a Y path, and simultaneously outputting the signals to an XY array antenna unit, wherein the sequence and the number of the switches of the X1.. Xn analog switch array and the switches of the Y1.. Yn analog switch array can be dynamically adjusted according to actual conditions in the subsequent operation process;
step 4, in the process of transmitting signals by the main processing MCU chip, if an electromagnetic pen exists in the antenna radiation area, the electromagnetic pen can receive signals S1 and S2 sent by XY antennas of the XY array antenna unit, and the electromagnetic pen can generate oscillation signals S3 and S4 ；
Step 5, after the main processing MCU chip finishes signal transmission, simultaneously converting an X1.. Xn analog switch array and a Y1.. Yn analog switch array switch into a receiving mode through a three-state gate, opening an operational amplifier part of a receiving circuit, and simultaneously amplifying, filtering, shaping and integrating received signals through X and Y channels by an X and Y array antenna unit in a T1.. Tn time period in an S5 waveform opened by the operational amplifier to obtain echo signals S6 and S7;
step 6, sampling the X and Y antenna echo integral signals S6 and S7 by two ADC of the main processing MCU chip hardware, ensuring the synchronism of any one coordinate point in X and Y sampling, and calculating the position and the inclination angle of the electromagnetic pen in a two-dimensional plane coordinate through the voltage difference of adjacent antennas;
step 7, because the pen pressure change of the electromagnetic pen is realized by changing the value of a capacitance device or an inductance device, the frequency of the electromagnetic wave is slightly changed, a certain voltage difference is generated after passing through a phase discriminator according to the principle of the phase discriminator, a certain amount of integration is carried out on the voltage difference, and the voltage value obtained after the integration of the phase discriminator can be converted into the pressure value of the pen by referring to the maximum change value of the pressure corresponding to the frequency designed by the electromagnetic pen;
and 8, finally, outputting data such as coordinates, inclination angles, pressure and the like through interfaces such as USB, UART, I2C, SPI and the like of the main processing MCU chip.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113686230A (en) * | 2021-09-06 | 2021-11-23 | 深圳市绘王动漫科技有限公司 | Method, device and system for solving quick scribing and breaking |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113686230A (en) * | 2021-09-06 | 2021-11-23 | 深圳市绘王动漫科技有限公司 | Method, device and system for solving quick scribing and breaking |
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