Pointing stick and method for identifying movement of the pointing stick

Abstract

The present invention discloses a pointing stick and a method for identifying the movement of the pointing stick. The pointing stick includes a substrate, a PCB board, and an operating stick assembly. The PCB board is provided with an MCU processor. The MCU processor has two reference resistors R connected in series. After the two reference resistors R are connected in series, one end is grounded and the other end is connected to a sensor power supply terminal VS. Eight sensor resistors are printed on the back of the PCB board. The eight sensor resistors are all printed with conductive ink. The eight sensor resistors form four groups of Wheatstone bridge circuits. The present invention is provided with eight sensors printed with conductive ink on the PCB board, and the motion detection of the pointing stick can be realized without the need for peripheral resistors. The four groups of Wheatstone bridge circuits composed of eight sensor resistors are simpler and more practical than traditional pointing stick sensor circuits, and are easy to produce, easy to maintain, and more reliable. The pointing stick of the present invention can reduce production costs, increase product qualification rate, and reduce power consumption.

Description

Technical Field

[0001] The present invention relates to a pointing stick, and in particular to a pointing stick and a method for identifying movement of the pointing stick. Background Art

[0002] A pointing stick is a device that controls the movement of a computer mouse cursor and performs mouse-related functions.

[0003] Currently, trackballs and pointing sticks on the market have one common feature: by moving the trackball or pressing the device with your fingers, you can control the movement of the computer mouse cursor and realize the left, middle, and right button functions.

[0004] The following are the defects of the pointing stick in the prior art:

[0005] like Figure 7 As shown, Figure 7 The following is a typical pointing stick circuit schematic. Resistors R1, R2, R3, and R4 are the pressure sensors for the X and Y axes. Resistors R1 and R2 are on the X axis, and resistors R3 and R4 are on the Y axis. Curvilinearly: When no action is taken, voltages Vx, Vy, and V1 are equal, and voltages Vz and V2 are equal. Voltages Vx and V1, Vy and V1, and Vz and V2 form three Wheatstone bridges.

[0006] When the cursor swings in the positive X-axis direction, resistor R1 increases and resistor R2 decreases, causing the X-axis output voltage to decrease, indicating the cursor is moving in the positive direction. The Y-axis operates in the same way: when pressed downward, resistors R1, R2, R3, and R4 simultaneously increase in voltage, decreasing the voltage at Vz, thus identifying click and click-and-drag functions. X-axis speed is related to VX2-V1, Y-axis speed is related to VY2-V1, and Z-axis pressure is related to Vz-V2.

[0007] VS is the abbreviation of VCCSensor: sensor power supply, generally 2.8V, 2.6V, 2.4V, 2.2V, 2.0V, etc.

[0008] This design only requires 4 pressure sensors, but it also has very high requirements: Since the reference voltage V2 of the Z-axis Vz is composed of the fixed resistors R6, R9, and R10, the parallel equivalent resistance of the resistors R1, R2, R3, and R4 must be very close in each batch to ensure that Vz and V2 are equal when there is no pressure. At the same time, in order to make the voltages of Vx, Vy, and V1 equal, the resistance values ​​of the resistors R1, R2, R3, and R4 must also be very close. In addition, the above resistors R5, R6, R7, R8, R9, and R10 must use high-precision resistors with a value of 1% or 0.1% or more. The price is relatively high.

[0009] Therefore, in this area, there are two options:

[0010] 1) Using a 350-ohm strain gauge as a pressure sensor can achieve very precise resistance values, but this sensor is relatively expensive, and due to its low resistance, power consumption cannot be further reduced.

[0011] 2) When using conductive ink as a piezoelectric sensor, a typical single resistor is several thousand ohms. Laser trimming is then used to correct the resistance of each resistor, which requires dedicated equipment and high resistance accuracy requirements for resistors R1, R2, R3, and R4. This can easily lead to scrapping or rework during production, necessitating high production requirements. Summary of the Invention

[0012] In view of the deficiencies in the prior art, the present invention aims to solve the technical problem of providing a pointing stick and a method for identifying the movement of the pointing stick. The purpose of designing the pointing stick is to reduce production costs, increase product qualification rate, and reduce power consumption.

[0013] To solve the above technical problems, the present invention is implemented through the following solution: A pointing stick of the present invention includes a substrate, a PCB board, and an operating stick assembly. The PCB board is provided with an MCU processor, and the MCU processor has two reference resistors R connected in series. The two reference resistors R are connected in series with one end being grounded and the other end being connected to a sensor power supply terminal VS. The back of the PCB board is printed with eight sensor resistors, each of which is printed with conductive ink, and includes:

[0014] Resistors RX1 and RX2 located in the X-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RX3 and RX4 located away from the printed positions of the resistors RX1 and RX2 and inaccessible to the operating lever assembly;

[0015] Resistors RY1 and RY2 located in the Y-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RY3 and RY4 located away from the printed positions of the resistors RY1 and RY2 and inaccessible to the operating lever assembly;

[0016] The eight sensor resistors form four groups of Wheatstone bridge circuits, and the four groups of Wheatstone bridge circuits include:

[0017] A first Wheatstone bridge circuit, wherein one end of the resistor RX1 and the resistor RX3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0018] A second Wheatstone bridge circuit, wherein one end of the resistor RX2 and the resistor RX4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0019] A third Wheatstone bridge circuit, wherein one end of the resistor RY2 and the resistor RY4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0020] In the fourth Wheatstone bridge circuit, one end of the resistor RY1 and the resistor RY3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS.

[0021] Furthermore, the pointing stick further includes a gasket, which is disposed between the substrate and the PCB board and is fixed to the gasket, the substrate and the PCB board by fasteners.

[0022] Furthermore, the gasket is provided with a first avoidance hole, a second avoidance hole and a third avoidance hole;

[0023] The second avoidance hole surrounds the resistor RX1 and the resistor RX2, and the resistor RY1 and the resistor RY2;

[0024] The first avoidance hole surrounds the resistor RX3 and the resistor RY3;

[0025] The third avoiding hole surrounds the resistor RX4 and the resistor RY4.

[0026] Furthermore, the operating lever assembly includes a rocker arm, a pressing piece sleeved outside the rocker arm, and a pressing piece sleeve sleeved outside the pressing piece.

[0027] A method for identifying the movement of the pointing stick, the method comprising:

[0028] Assuming that the input voltage of the sensor power supply terminal VS is VS, the voltage across the two reference resistors connected in series is VS / 2;

[0029] Assume that the voltage across the resistor RX1 and the resistor RX3 is VX1;

[0030] Assume that the voltage across the resistor RX2 and the resistor RX4 is VX2;

[0031] Assume that the voltage between the resistor RY1 and the resistor RY3 is VY1;

[0032] Assume that the voltage between the resistor RY2 and the resistor RY4 is VY2;

[0033] The MCU processor continuously performs differential operations on the voltages of VX1, VX2, VY1, and VY2 with VS / 2, and obtains four sets of differential values:

[0034] dVX1=VX1-VS / 2;

[0035] dVX2=VX2-VS / 2;

[0036] dVY1=VY1-VS / 2;

[0037] dVY2=VY2-VS / 2;

[0038] According to the four sets of differential values, the running speed of the cursor on the X axis controlled by the pointing stick is obtained as: dVX1-dVX2, and the running speed of the cursor on the Y axis controlled by the pointing stick is obtained as: dVY1-dVY2.

[0039] Furthermore, when the pointing stick is swung in any direction, one of the resistors RX1 and RX2 increases while the other decreases. During the resistance change of the resistors RX1 and RX2, the total voltage input to the resistors RX1 and RX2 remains unchanged.

[0040] When the pointing stick swings in any direction, one of the resistors RY1 and RY2 increases and the other decreases. During the resistance change of the resistors RY1 and RY2, the total voltage input to the resistors RY1 and RY2 remains unchanged.

[0041] Furthermore, when the pointing stick is pressed down, the resistors RX1, RX2, RX3, and RX4 increase in value at the same time, and the voltage sum of VX1+VX2+VY1+VY2 corresponding to the resistors RX1, RX2, RX3, and RX4 decreases. The MCU processor detects the decrease in the voltage sum of VX1+VX2+VY1+VY2 to determine whether the finger is pressing down.

[0042] Furthermore, the downward pressure of the pointing stick is proportional to the Z-axis voltage of the pointing stick, and the Z-axis voltage of the pointing stick is Vz=VX1+VX2+VY1+VY2.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The pointing stick of the present invention can realize motion detection of the pointing stick by printing 8 sensor resistors on a PCB board, and each sensor resistor is printed with conductive ink, without the need for external resistors.

[0045] 2. The four Wheatstone bridge circuits consisting of eight sensor resistors are simpler and more practical than traditional pointing stick sensor circuits. They are also easier to produce and maintain and have greater reliability.

[0046] 3. Compared with traditional pointing sticks, the pointing stick of the present invention reduces production costs, increases product qualification rate, and also reduces power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is an exploded view of the pointing stick of the present invention.

[0048] Figure 2 This is an assembly diagram of the pointing stick of the present invention.

[0049] Figure 3 This is a diagram showing the installation locations of the connector and MCU processor on the PCB of the present invention.

[0050] Figure 4 This is a structural diagram of the gasket of the present invention.

[0051] Figure 5 This is a first layout diagram of eight sensor resistors on a PCB board according to the present invention.

[0052] Figure 6 This is a second layout diagram of eight sensor resistors on a PCB board according to the present invention.

[0053] Figure 7 This is a typical pointing stick principle circuit diagram in the prior art.

[0054] Figure 8 This is a schematic diagram of the pointing stick sensor circuit of the present invention.

[0055] Figure 9 Schematic diagram of a Wheatstone bridge on a PCB board of the present invention.

[0056] Markings in the accompanying drawings: substrate 1, gasket 2, PCB board 3, fastener 4, rocker arm 5, pressing piece 6, pressing piece sleeve 7, connector 8, MCU processor 9, first avoidance hole 21, second avoidance hole 22, third avoidance hole 23. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the scope of protection of the present invention. Obviously, the embodiments described in the present invention are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0058] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0059] Example 1: The specific structure of the present invention is as follows:

[0060] Please refer to the attached Figure 1-6 、 Figure 8-9 A pointing stick according to the present invention includes a substrate 1, a PCB board 3, and an operating stick assembly. The PCB board 3 is provided with an MCU processor 9 and a connector 8. The MCU processor 9 has two reference resistors R connected in series. One end of the two reference resistors R is connected in series to ground, and the other end is connected to a sensor power supply terminal VS. Eight sensor resistors are printed on the back of the PCB board 3. The eight sensor resistors are all printed with conductive ink and include:

[0061] Resistors RX1 and RX2 located in the X-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RX3 and RX4 located away from the printed positions of the resistors RX1 and RX2 and inaccessible to the operating lever assembly;

[0062] Resistors RY1 and RY2 located in the Y-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RY3 and RY4 located away from the printed positions of the resistors RY1 and RY2 and inaccessible to the operating lever assembly;

[0063] The eight sensor resistors form four groups of Wheatstone bridge circuits, and the four groups of Wheatstone bridge circuits include:

[0064] A first Wheatstone bridge circuit, wherein one end of the resistor RX1 and the resistor RX3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0065] A second Wheatstone bridge circuit, wherein one end of the resistor RX2 and the resistor RX4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0066] A third Wheatstone bridge circuit, wherein one end of the resistor RY2 and the resistor RY4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS;

[0067] In the fourth Wheatstone bridge circuit, one end of the resistor RY1 and the resistor RY3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS.

[0068] A preferred technical solution of this embodiment: In order to ensure that there is enough space between the resistors RX1, RX2, RY1 and RY2, a gasket 2 is added. The gasket 2 is arranged between the substrate 1 and the PCB board 3 and the gasket 2, the substrate 1 and the PCB board 3 are fixed by fasteners 4.

[0069] The gasket 2 is provided with a first avoidance hole 21, a second avoidance hole 22 and a third avoidance hole 23;

[0070] The second avoiding hole 22 surrounds the resistor RX1 and the resistor RX2, and the resistor RY1 and the resistor RY2;

[0071] The first avoidance hole 21 surrounds the resistors RX3 and RY3, and the third avoidance hole 23 surrounds the resistors RX4 and RY4. By providing the first avoidance hole 21 and the third avoidance hole 23, the resistors RX3 and RY3, and the resistors RX4 and RY4 are not affected by the swing of the pointing stick.

[0072] A preferred technical solution of this embodiment: the operating lever assembly includes a rocker arm 5 , a pressing piece 6 sleeved outside the rocker arm 5 , and a pressing piece sleeve 7 sleeved outside the pressing piece 6 .

[0073] Example 2:

[0074] A method for identifying the movement of the pointing stick, the method comprising:

[0075] Assuming that the input voltage of the sensor power supply terminal VS is VS, the voltage across the two reference resistors connected in series is VS / 2;

[0076] Assume that the voltage across the resistor RX1 and the resistor RX3 is VX1;

[0077] Assume that the voltage across the resistor RX2 and the resistor RX4 is VX2;

[0078] Assume that the voltage between the resistor RY1 and the resistor RY3 is VY1;

[0079] Assume that the voltage between the resistor RY2 and the resistor RY4 is VY2;

[0080] The MCU processor continuously performs differential operations on the voltages of VX1, VX2, VY1, and VY2 with VS / 2, and obtains four sets of differential values:

[0081] dVX1=VX1-VS / 2;

[0082] dVX2=VX2-VS / 2;

[0083] dVY1=VY1-VS / 2;

[0084] dVY2=VY2-VS / 2;

[0085] According to the four sets of differential values, the running speed of the cursor on the X axis controlled by the pointing stick is obtained as: dVX1-dVX2, and the running speed of the cursor on the Y axis controlled by the pointing stick is obtained as: dVY1-dVY2.

[0086] When the pointing stick is swung in any direction, one of the resistors RX1 and RX2 increases and the other decreases. During the resistance changes of the resistors RX1 and RX2, the total voltage input to the resistors RX1 and RX2 remains unchanged.

[0087] When the pointing stick swings in any direction, one of the resistors RY1 and RY2 increases and the other decreases. During the resistance change of the resistors RY1 and RY2, the total voltage input to the resistors RY1 and RY2 remains unchanged.

[0088] When the pointing stick is pressed down, the resistors RX1, RX2, RX3, and RX4 increase in value at the same time, and the voltage sum of VX1+VX2+VY1+VY2 corresponding to the resistors RX1, RX2, RX3, and RX4 decreases. The MCU processor detects the decrease in the voltage sum of VX1+VX2+VY1+VY2 to determine the finger pressing down.

[0089] The downward pressure of the pointing stick is proportional to the Z-axis voltage of the pointing stick, and the Z-axis voltage of the pointing stick is Vz=VX1+VX2+VY1+VY2.

[0090] Example 3:

[0091] Since the sensor resistors are made by ink printing, it cannot be guaranteed that the resistance of each sensor resistor is equal. In the present invention, it is only necessary to ensure that the resistance values ​​of the eight sensor resistors printed with conductive ink on a PCB board are within a certain range. It is not necessary for the resistance values ​​of each sensor resistor to be equal. This is a relatively simple task for the eight sensor resistors printed together.

[0092] Furthermore, to minimize the tolerance of each resistor, VS / 2 is introduced as the reference voltage, rather than using VX1 and VX2, and VY1 and YY2 directly as the differential inputs. Because VS / 2 is very accurate, this doubles the differential input offset voltage. In actual production, using the method of this invention, the tolerance of each resistor is within 40%, ensuring normal operation. Compared to the 0.5% accuracy requirement of the classic circuit above, this is much simpler, requires no laser trimming, and can be successfully produced with a single printing process.

[0093] To achieve the click function, the present invention requires four differential operations, while conventional pointing stick circuits require three. This requires one more differential operation than conventional ones. However, since only 40% accuracy is required for the eight sensor resistors within a single PCB, the resistance requirement for each sensor resistor is less stringent. Therefore, a higher resistance can be achieved for each sensor resistor, such as 10kΩ. The eight sensor resistors have an equivalent resistance of 5kΩ. This saves nearly half the power ((2200 / 5000) x (4 / 3) = 58.7%) compared to the 2.2kΩ resistance of a single resistor in a conventional pointing stick circuit, or an equivalent resistance of 2.2kΩ for four sensors. This also reduces power consumption by 50% ((350 / 5000) x (4 / 3) = 9.3%), compared to a 350Ω strain gauge sensor.

[0094] Moreover, the pointing stick sensor of the present invention only requires printing eight sensor resistors at one time, without requiring any peripheral fixed resistors. In contrast, the conventional pointing stick circuit requires six high-precision resistors (R5, R6, R7, R8, R9, R10) and associated capacitors. Therefore, the sensor circuit of the pointing stick of the present invention is much simpler than the sensor circuit of the conventional pointing stick, and is easier to produce and maintain, and has higher reliability.

[0095] In summary, the present invention's pointing stick utilizes eight sensor resistors printed on a PCB, each using conductive ink, eliminating the need for external resistors and enabling motion detection. The present invention's pointing stick, comprised of four Wheatstone bridge circuits comprised of eight sensor resistors, is simpler and more practical than conventional pointing stick sensor circuits. It is also easier to manufacture and maintain, and offers greater reliability. Compared to conventional pointing sticks, the present invention reduces production costs, increases product yield, and reduces power consumption.

[0096] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, is also included in the patent protection scope of the present invention.

Claims

1. A pointing stick, comprising a substrate (1), a PCB (3), and an operating stick assembly, wherein the PCB (3) is provided with an MCU (9), and the MCU (9) is built with two reference resistors R connected in series, one end of the two reference resistors R being connected in series to ground, and the other end being connected to a sensor power supply terminal VS, characterized in that: Eight sensor resistors are printed on the back of the PCB board (3), and the eight sensor resistors are all printed with conductive ink, which includes: Resistors RX1 and RX2 located in the X-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RX3 and RX4 located away from the printed positions of the resistors RX1 and RX2 and inaccessible to the operating lever assembly; Resistors RY1 and RY2 located in the Y-axis direction and capable of being touched by the operating lever assembly and deformed to change resistance, and resistors RY3 and RY4 located away from the printed positions of the resistors RY1 and RY2 and inaccessible to the operating lever assembly; The eight sensor resistors form four groups of Wheatstone bridge circuits, and the four groups of Wheatstone bridge circuits include: A first Wheatstone bridge circuit, wherein one end of the resistor RX1 and the resistor RX3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS; A second Wheatstone bridge circuit, wherein one end of the resistor RX2 and the resistor RX4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS; A third Wheatstone bridge circuit, wherein one end of the resistor RY2 and the resistor RY4 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS; In the fourth Wheatstone bridge circuit, one end of the resistor RY1 and the resistor RY3 connected in series is grounded, and the other end is connected to the sensor power supply terminal VS.

2. The pointing stick according to claim 1, wherein: The pointing stick further comprises a gasket (2), which is arranged between the substrate (1) and the PCB (3) and is fixed to the gasket (2), the substrate (1) and the PCB (3) by a fastener (4).

3. The pointing stick according to claim 2, wherein: The gasket (2) is provided with a first avoidance hole (21), a second avoidance hole (22) and a third avoidance hole (23); The second avoidance hole (22) surrounds the resistor RX1 and the resistor RX2, and the resistor RY1 and the resistor RY2; The first avoidance hole (21) surrounds the resistor RX3 and the resistor RY3; The third avoidance hole (23) surrounds the resistor RX4 and the resistor RY4.

4. The pointing stick according to claim 1, wherein: The operating rod assembly comprises a rocker arm (5), a pressing piece (6) sleeved outside the rocker arm (5), and a pressing piece sleeve (7) sleeved outside the pressing piece (6).

5. A method for identifying the movement of the pointing stick, characterized in that: The method comprises the pointing stick according to any one of claims 1 to 4.

6. The method according to claim 5, characterized in that The method is: Assuming that the input voltage of the sensor power supply terminal VS is VS, the voltage across the two reference resistors connected in series is VS / 2; Assume that the voltage across the resistor RX1 and the resistor RX3 is VX1; Assume that the voltage across the resistor RX2 and the resistor RX4 is VX2; Assume that the voltage between the resistor RY1 and the resistor RY3 is VY1; Assume that the voltage between the resistor RY2 and the resistor RY4 is VY2; The MCU processor continuously performs differential operations on the voltages of VX1, VX2, VY1, and VY2 with VS / 2, and obtains four sets of differential values: dVX1=VX1-VS / 2; dVX2=VX2-VS / 2; dVY1=VY1-VS / 2; dVY2=VY2-VS / 2; According to the four sets of differential values, the running speed of the cursor on the X axis controlled by the pointing stick is obtained as: dVX1-dVX2, and the running speed of the cursor on the Y axis controlled by the pointing stick is obtained as: dVY1-dVY2.

7. The method according to claim 6, characterized in that When the pointing stick is swung in any direction, one of the resistors RX1 and RX2 increases and the other decreases. During the resistance changes of the resistors RX1 and RX2, the total voltage input to the resistors RX1 and RX2 remains unchanged. When the pointing stick swings in any direction, one of the resistors RY1 and RY2 increases and the other decreases. During the resistance change of the resistors RY1 and RY2, the total voltage input to the resistors RY1 and RY2 remains unchanged.

8. The method according to claim 6, characterized in that When the pointing stick is pressed down, the resistors RX1, RX2, RX3, and RX4 increase in value at the same time, and the voltage sum of VX1+VX2+VY1+VY2 corresponding to the resistors RX1, RX2, RX3, and RX4 decreases. The MCU processor detects the decrease in the voltage sum of VX1+VX2+VY1+VY2 to determine the finger pressing down.

9. The method according to claim 7, characterized in that The downward pressure of the pointing stick is proportional to the Z-axis voltage of the pointing stick, and the Z-axis voltage of the pointing stick is Vz=VX1+VX2+VY1+VY2.

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