Key stroke detection scheme applied to magnetic axis keyboard

Abstract

According to the key stroke detection scheme applied to the magnetic axis keyboard, the two magnetic sensors are adopted to detect the moving position of one magnet at the same time, and the magnet can move between the two magnetic sensors along with pressing of the key, so that the sensitivity of magnetic field intensity detection can be greatly enhanced, namely, the precision of magnet position detection is enhanced; therefore, the pressing position of the magnetic axis key can be detected more accurately.

Description

Technical Field

[0001] The invention patent relates to a key stroke detection solution for a magnetic axis keyboard. Background Art

[0002] The current magnetic axis keyboard market is highly competitive, and the requirements for key travel detection accuracy are getting higher and higher. For example, if the detection accuracy is required to be 0.01mm, the design difficulty will be greatly increased. The present invention aims to provide a new magnetic axis detection solution to improve the accuracy of key detection. Summary of the invention

[0003] The purpose of the present invention is to improve the accuracy of magnetic axis key detection. Two magnetic sensors are used to simultaneously detect the moving position of a magnet. The magnet will move between the two magnetic sensors as the key is pressed, thereby greatly enhancing the sensitivity of magnetic field strength detection, that is, enhancing the accuracy of magnet position detection, so that the pressed position of the magnetic axis key can be detected more accurately.

[0004] The embodiment of the present invention is a key stroke detection scheme for a magnetic axis keyboard, which has the following characteristics: (1) Two magnetic sensors are used to simultaneously detect the moving position of a magnet. The magnet is placed between the two sensors. The magnet moves between the two magnetic sensors as the key is pressed, which can increase the detection accuracy. (2) The magnet, magnetic sensor 1, and magnetic sensor 2 may be in a straight line or not, and the selection can be made based on the actual product structure; (3) The initial distance between the magnet, magnetic sensor 1, and magnetic sensor 2 can be adjusted according to actual user needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The above and other features, properties and advantages of the present invention will become more apparent through the following description of the embodiments in conjunction with the accompanying drawings, in which the same reference numerals always represent the same features, wherein: Figure 1 A system block diagram showing a scheme for detecting the key stroke of a magnetic axis keyboard according to the present invention is shown; Figure 2 A schematic diagram showing signal changes during the key stroke process of a magnetic axis keyboard key is shown; Attached photos

[0006] 100 —— A key stroke detection scheme for a magnetic axis keyboard according to the present invention 101 —— MCU controller; 102 —— Magnetic sensor 1; 103 —— Magnetic sensor 2; 104 - magnet, located in the key; 200 —— A schematic diagram of signal changes during the key stroke process of a magnetic axis keyboard according to the present invention; 201 —— Signal change of magnetic sensor 1; 202 —— Signal change of magnetic sensor 2; 203 —— The difference between the signal changes of magnetic sensor 1 and magnetic sensor 2; DETAILED DESCRIPTION

[0007] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0008] Embodiments of the present invention will now be described with reference to the accompanying drawings in detail. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used in all drawings to represent the same or similar parts. In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein. In addition, it is required to understand the present invention not only by the actual terms used, but also by the meaning implied by each term.

[0009] like Figure 1 As shown, the present invention uses two magnetic sensors to simultaneously detect the moving position of a magnet, and the magnet moves between the two magnetic sensors as a key is pressed.

[0010] For ease of understanding, we assume that the magnetic sensor converts the magnetic field strength into a voltage signal, and the voltage amplitude is proportional to the magnetic field strength. Since the magnetic field strength is inversely proportional to the distance, that is, the farther the distance, the weaker the magnetic field strength; conversely, the closer the distance, the stronger the magnetic field strength. Assume that when the magnet is not pressed at the beginning, the distance between the magnetic sensor 1 and the magnet is d1, and the distance between the magnetic sensor 2 and the magnet is d2. At this time, the magnetic sensor 1 is closest to the magnet, the magnetic field strength is the largest, and the output voltage is the maximum value V1max; similarly, the magnetic sensor 2 is farthest from the magnet, the magnetic field strength is the smallest, and the output voltage is the minimum value V2min.

[0011] As the key is pressed down, the distance d1 increases, the magnetic field strength detected by magnetic sensor 1 decreases, and at the same time d2 decreases, the magnetic field strength detected by magnetic sensor 2 increases. When the key is pressed to the bottom, magnetic sensor 1 is farthest from the magnet, the magnetic field strength is the smallest, and the output voltage of magnetic sensor 1 is the minimum value V1min; similarly, magnetic sensor 2 is closest to the magnet, the magnetic field strength is the largest, and the output voltage of magnetic sensor 2 is the maximum value V2max.

[0012] We use the difference between the two sensor voltages to represent the button position, that is, the output voltage of magnetic sensor 1 minus the output voltage of magnetic sensor 2, that is: Initial position voltage difference Vtop: Vtop=V1max-V2min When the button is pressed to the bottom, the voltage difference Vbot is: Vbot=V1min-V2max The voltage variation range from top to bottom of the button, that is, the signal dynamic range is: Vtop-Vbot=(V1max-V2min)-(V1min-V2max) = (V1max+V2max)-(V1min-V2min) For easier understanding, we assume that Vmax=V1max=V2max, Vmin=V1min=V2min, then: Vtop-Vbot=2 * (Vmax-Vmin) Compared with the detection of a single magnetic sensor, whose signal dynamic range is Vmax-Vmin, the voltage dynamic range is increased by 2 times after the present invention adopts two magnetic sensors, that is, the signal-to-noise ratio is increased by 2 times. After the signal is quantized by the MCU controller, the position of the magnet can be detected more accurately, that is, the position of the button press can be detected more accurately.

[0013] In addition, Figure 2 As shown, the current magnetic axis keyboard adopts only magnetic sensor 2. As the key is pressed, its signal changes as shown in Figure 2 As shown in 202, since the magnetic field strength and distance are exponentially related, in the early stage of key pressing, the magnetic field strength changes very little at the same pressing distance, that is, the signal changes very little, and it is difficult to improve the resolution of the key stroke. The present invention uses a dual sensor, that is, adding a magnetic sensor 1, and its signal changes as the key is pressed. Figure 2 As shown in 201, the difference between the output voltages of the two sensors is used to characterize the key stroke, and the signal changes during the key pressing process. Figure 2 As shown in 203, throughout the entire key stroke, the change in magnetic field strength at the same pressing distance is significantly increased, thereby greatly improving the key pressing stroke detection resolution, especially the detection resolution of the front section of the key is more significantly improved. The present invention can greatly improve the performance of the keyboard and user experience.

[0014] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A key stroke detection scheme for a magnetic axis keyboard, characterized in that: The magnetic axis keyboard key travel detection scheme uses two magnetic sensors to simultaneously detect the moving position of a magnet. The magnet is placed between the two sensors, and the magnet moves between the two magnetic sensors as the key is pressed.

2. The key stroke detection scheme for a magnetic axis keyboard as claimed in claim 1, characterized in that: The magnet, the magnetic sensor 1 and the magnetic sensor 2 may be in a straight line or may not be in a straight line.

3. The key stroke detection scheme for a magnetic axis keyboard as claimed in claim 1, characterized in that: The initial distances among the magnet, magnetic sensor 1 and magnetic sensor 2 are set according to actual user needs.

4. The key stroke detection scheme for a magnetic axis keyboard as claimed in claim 1, characterized in that: There may be one or more communication lines between the magnetic sensor 1 and the magnetic sensor 2 and the MCU controller, and the transmitted signal may be a digital signal or an analog signal, or partly a digital signal and partly an analog signal.

5. The key stroke detection scheme for a magnetic axis keyboard as claimed in claim 1, characterized in that: The magnet is placed in the button and moves up and down as the button is pressed, thereby changing the distance between the magnet and the magnetic sensor 1 and the magnetic sensor 2.

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