A step counting circuit module for a gait sensing unit of liquid metal / PDMS porous sponge

Abstract

This utility model discloses a step counting circuit module for a liquid metal / PDMS porous sponge gait sensing unit, comprising: a signal conditioning unit for receiving and processing the alternating voltage signal generated by the gait sensing unit and outputting shaped counting pulses; a counting decoding unit, the input of which is connected to the output of the signal conditioning unit, for counting and decoding the counting pulses; a display unit connected to the output of the counting decoding unit for displaying the count value; and a power supply unit for supplying power to the signal conditioning unit, the counting decoding unit, and the display unit; wherein the alternating voltage signal is stepped down before acquisition, and the counting decoding unit uses a CD4026 chip to implement decimal counting and 7-segment code decoding.

Description

Technical Field

[0001] This utility model belongs to the field of circuits, specifically relating to a step counting circuit module for a liquid metal / PDMS porous sponge gait sensing unit. Background Technology

[0002] With the fast pace of life and the challenges of an aging population, health problems such as foot diseases, osteoarthritis, neurological disorders, and diabetes are on the rise, often accompanied by abnormal gait changes. Gait abnormalities are not only early warning signs of many diseases but also have a significant impact on an individual's daily life and quality of life, leading to the development of gait sensors specifically for the elderly.

[0003] The liquid metal PDMS porous sponge TENG gait sensing unit generates alternating charge output through changes in foot pressure, and its signal is characterized by random pulse amplitude and large noise interference.

[0004] For example, Chinese patent CN202511433084.2 discloses a gait sensing unit and its preparation method based on a triboelectric nanogenerator of liquid metal / PDMS porous sponge. This patent discloses a gait sensor and its preparation method, but its application in step counting and supporting circuits are still lacking. Utility Model Content

[0005] To address some technical problems existing in the prior art, this utility model proposes a step-counting circuit module for a liquid metal / PDMS porous sponge gait sensing unit, aiming to provide a step-counting circuit module for the liquid metal / PDMS porous sponge gait sensing unit. This utility model can effectively condition the data of the gait sensing unit and realize the step-counting function.

[0006] To achieve the above objectives, this utility model provides a step counting circuit module for a liquid metal / PDMS porous sponge gait sensing unit, comprising: The signal conditioning unit is used to receive and process the alternating voltage signal generated by the gait sensing unit and output the shaped counting pulse. The counting and decoding unit has its input terminal connected to the output terminal of the signal conditioning unit and is used to count and decode the counting pulses. The display unit is connected to the output of the counting decoding unit and is used to display the count value; And a power supply unit, which supplies power to the signal conditioning unit, the counting and decoding unit and the display unit; The alternating voltage signal is stepped down before being acquired, and the counting and decoding unit uses a CD4026 chip to implement decimal counting and 7-segment code decoding.

[0007] In one specific embodiment, the signal conditioning unit sequentially includes: A voltage divider circuit is used to divide the high-amplitude alternating voltage output by the gait sensing unit; A rectifier circuit, connected to the voltage divider circuit, is used to convert the divided alternating voltage into a unipolar pulse signal; A filtering circuit, connected to the rectifier circuit, is used to filter out noise in the unipolar pulse signal; and a waveform shaping circuit, connected to the filtering circuit, is used to shape the filtered signal into a square wave signal with steep edges, as the counting pulse.

[0008] In one specific embodiment, the waveform shaping circuit is a Schmitt trigger, which includes an LM393 voltage comparator; the non-inverting input of the LM393 voltage comparator receives the filtered signal, the inverting input is connected to a reference voltage, and the output is connected to the non-inverting input through a feedback resistor to form positive feedback and generate a hysteresis effect.

[0009] In one specific embodiment, the signal conditioning unit further includes a monostable trigger circuit, the input terminal of which is connected to the output terminal of the waveform shaping circuit, for converting the square wave signal into a single pulse signal with a fixed pulse width, so as to be used as the counting pulse input to the counting decoding unit.

[0010] In one specific embodiment, the monostable trigger circuit is implemented using an NE555 timer, whose trigger terminal receives the square wave signal and determines the fixed pulse width by a timing resistor and a timing capacitor connected between its threshold terminal and discharge terminal.

[0011] In one specific embodiment, the clock input terminal of the CD4026 chip receives the counting pulse, and its 7-segment output pin is connected to the display unit through a current-limiting resistor; the display enable pin of the CD4026 chip is connected to a high level, the clock disable pin is grounded, and the reset pin is connected to the power supply through a pull-up resistor.

[0012] In one specific embodiment, the display unit is a common cathode seven-segment display tube with its common terminal grounded, and its segment selection pin is connected to the 7-segment output pin of the CD4026 chip through the current limiting resistor.

[0013] In one specific embodiment, the power supply unit includes a voltage regulator chip for converting the external input voltage into a stable 5V DC voltage to power the CD4026 chip, waveform shaping circuit, and monostable trigger circuit.

[0014] In one specific embodiment, the step counting circuit module integrates a low-power management function, which controls the display enable pin level of the CD4026 chip to turn off the display unit in the idle state to reduce power consumption.

[0015] In another aspect of this utility model, a smart shoe is provided, including a shoe body, wherein the shoe body has the aforementioned step counting circuit module and a gait sensing unit for generating alternating voltage signals; the output terminal of the gait sensing unit is electrically connected to the input terminal of the signal conditioning unit of the step counting circuit module.

[0016] Compared with the prior art, the present invention has the following significant advantages: This invention leverages the integrated advantages of the CD4026 chip, combined with signal conditioning circuit design, to achieve efficient counting and display of the output signal from the gait sensing unit. The module features high integration, low power consumption, and strong anti-interference capabilities, meeting the step counting requirements of flexible wearable devices and providing crucial circuit support for the practical application of liquid metal PDMS porous sponge TENG. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall principle of the step counting circuit module according to a specific embodiment of this utility model. Detailed Implementation

[0018] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.

[0019] Example 1 like Figure 1 As shown, the first embodiment of this utility model provides a step counting circuit module for a liquid metal / PDMS porous sponge gait sensing unit, comprising: The signal conditioning unit is used to receive and process the alternating voltage signal generated by the gait sensing unit and output the shaped counting pulse. The counting and decoding unit has its input terminal connected to the output terminal of the signal conditioning unit and is used to count and decode the counting pulses. The display unit is connected to the output of the counting decoding unit and is used to display the count value; And a power supply unit, which supplies power to the signal conditioning unit, the counting and decoding unit and the display unit; The alternating voltage signal is stepped down before being acquired, and the counting and decoding unit uses a CD4026 chip to implement decimal counting and 7-segment code decoding.

[0020] In this embodiment, the signal conditioning unit sequentially includes: A voltage divider circuit is used to divide the high-amplitude alternating voltage output by the gait sensing unit; A rectifier circuit, connected to the voltage divider circuit, is used to convert the divided alternating voltage into a unipolar pulse signal; A filtering circuit, connected to the rectifier circuit, is used to filter out noise in the unipolar pulse signal; and a waveform shaping circuit, connected to the filtering circuit, is used to shape the filtered signal into a square wave signal with steep edges, as the counting pulse.

[0021] In this embodiment, the waveform shaping circuit is a Schmitt trigger, which includes an LM393 voltage comparator. The non-inverting input of the LM393 voltage comparator receives the filtered signal, the inverting input is connected to a reference voltage, and the output is connected to the non-inverting input through a feedback resistor to form positive feedback and generate a hysteresis effect.

[0022] In this embodiment, the signal conditioning unit further includes a monostable trigger circuit. The input terminal of the monostable trigger circuit is connected to the output terminal of the waveform shaping circuit, and is used to convert the square wave signal into a single pulse signal with a fixed pulse width, so as to input the counting pulse to the counting decoding unit.

[0023] In this embodiment, the monostable trigger circuit is implemented using an NE555 timer. Its trigger terminal receives the square wave signal, and the fixed pulse width is determined by a timing resistor and a timing capacitor connected between its threshold terminal and discharge terminal.

[0024] In this embodiment, the clock input terminal of the CD4026 chip receives the counting pulse, and its 7-segment output pin is connected to the display unit through a current-limiting resistor; the display enable pin of the CD4026 chip is connected to a high level, the clock disable pin is grounded, and the reset pin is connected to the power supply through a pull-up resistor.

[0025] In this embodiment, the display unit is a common cathode seven-segment display tube with its common terminal grounded, and its segment selection pin is connected to the 7-segment output pin of the CD4026 chip through the current limiting resistor.

[0026] In this embodiment, the power supply unit includes a voltage regulator chip for converting the external input voltage into a stable 5V DC voltage to power the CD4026 chip, waveform shaping circuit, and monostable trigger circuit.

[0027] In this embodiment, the step counting circuit module integrates a low-power management function, which controls the display enable pin level of the CD4026 chip to turn off the display unit in the idle state to reduce power consumption.

[0028] In another embodiment, a smart shoe is provided, including a shoe body, wherein the shoe body has a built-in step counting circuit module provided in the first embodiment, and a gait sensing unit for generating an alternating voltage signal; the output terminal of the gait sensing unit is electrically connected to the input terminal of the signal conditioning unit of the step counting circuit module.

[0029] The technical details of the first embodiment will be further described below.

[0030] I. General Requirements of Technical Solution The pedometer circuit module includes a signal conditioning unit, a CD4026 counting and decoding unit, a display unit, and a power supply unit. The overall circuit diagram is shown below. Figure 1 As shown.

[0031] Signal conditioning: The alternating voltage output by the gait sensing unit (typical amplitude 0.5V-5V, frequency 0.5Hz-2Hz) is converted into a unipolar pulse by a rectifier bridge, the filter capacitor removes high-frequency noise, and the Schmitt trigger shapes the irregular pulse into a steep square wave (rise edge ≤100ns) to meet the CLK input requirements of CD4026 (minimum pulse width 110ns@5V).

[0032] Counting and decoding: The CD4026 receives the shaped pulse on the CLK pin (pin 1), triggering a rising edge count with each step. The internal decoding circuit converts the count value into a 7-segment code, which drives the digital tube display (0-9 cycle) through the AG pin. When the count reaches 9, the CARRY pin (pin 3) outputs a high level, which can be cascaded to extend the ten-digit count.

[0033] Display driver: The common terminal of the common cathode seven-segment tube is grounded, and the segment selection pin is connected to the CD4026 output through a 1kΩ current limiting resistor to ensure that the current of each segment is ≤5mA (the maximum sink current of CD4026 is 0.34mA@5V, which meets the driving requirements).

[0034] 3.3 Key Circuit Design Signal conditioning circuit: Rectifier bridge: SB1040 Schottky diode (forward voltage drop 0.3V, fast response speed) is selected to reduce small signal loss; Filtering capacitors: 10μF + 0.1μF ceramic capacitors in parallel to filter out low-frequency ripple and high-frequency noise; CD4026 configuration: CLKN (pin 2) grounded, DIS_EI (pin 5) connected to VDD, RST (pin 15) connected to VDD (can be connected via pull-up resistor), reset button connected to ground; Digital tube: 0.56-inch common cathode digital tube (such as SM410564), segment selection pin is connected in series with a 1kΩ current limiting resistor (calculation: (3.3V-0.7V) / 1kΩ=2.6mA, which meets the output capability of CD4026).

[0035] 3.4 Low power consumption design CMOS device (CD4026, quiescent current ≤10μA) was selected. The digital tube uses dynamic scanning display (when counting multiple digits) to reduce average power consumption; Power Management: The display unit is turned off when idle (DIS_EI pin is connected to low level), and is automatically woken up by gait detection.

[0036] 4. Component Selection Table Module component model / parameter function The SB1040 signal conditioning rectifier diode (1A / 40V Schottky) rectifies alternating signals into unipolar signals. A 10μF / 16V electrolytic capacitor and a 0.1μF ceramic capacitor filter out noise and stabilize the signal. The CD4026BM counter chip (SOP16 package) implements 0-9 counting and 7-segment decoding. The display features a 0.56-inch common cathode digital tube (red) that shows the number of steps. 1kΩ current-limiting resistor, 0805 surface mount resistor (7 pieces), for protecting the segment selection pins of the digital display. 5. Debugging and Performance Testing Signal conditioning test: Use a function generator to simulate the TENG output (1Hz, 1Vpp sine wave), and observe the Schmitt trigger output with an oscilloscope. A standard square wave of 5V / 0V should be obtained without glitches.

[0037] Counting accuracy test: Manually press the gait sensor unit 10 times, the digital tube should display "10" (when cascaded), with an error of ≤1 time.

[0038] 6. Application Scenarios This module can be directly integrated into devices such as smart insoles and rehabilitation training shoes. By connecting to the electrodes of the liquid metal PDMS porous sponge gait sensing unit, it can monitor the user's walking steps in real time, providing data support for health assessment and exercise analysis.

[0039] II. Connection between the signal conditioning module and the sensor Sensor output (2 electrode pins): The positive pin of the sensor (outputs 18–112V alternating voltage) is connected to the input terminal of the voltage divider circuit (one end of R1) via a wire. The negative pin of the sensor is directly connected to the circuit common ground (GND).

[0040] Voltage divider circuit (R1=1MΩ metal film resistor, R2=47kΩ precision resistor): The other end of R1 is connected in series with one end of R2, and the series node (voltage divider point) is connected to the input terminal of the bridge rectifier circuit through a wire; The other end of R2 is directly connected to GND.

[0041] Bridge rectifier circuit (4 1N4007 diodes, D1~D4): Connect the positive terminal of D1 to the voltage divider point, and connect the negative terminal of D1 to the negative terminal of D2; Connect the positive terminal of D3 to GND, and connect the negative terminal of D3 to the positive terminal of D4. When the positive terminal of D2 is connected to the negative terminal of D4, it serves as the positive terminal (+) of the rectifier output. When the negative terminal of D1 is connected to the negative terminal of D3, it serves as the negative terminal (-, connected to GND). The positive terminal of the rectified output is connected to the input terminal of the second-order RC filter circuit via a wire.

[0042] Second-order RC filter circuit (R3=10kΩ, C1=0.1μF; R4=2.2kΩ, C2=0.22μF): One end of R3 is connected to the positive terminal of the rectifier output, and the other end is connected to one end of C1 (first-stage filter node). The other end of C1 is connected to GND; The first-stage filter node is connected to one end of R4 via a wire, and the other end of R4 is connected to one end of C2 (the second-stage filter node, i.e., the output of the signal conditioning module). The other end of C2 is connected to GND.

[0043] III. Connection of Waveform Shaping Module (Hysteresis Comparator) Core component: LM393 voltage comparator (U1), 5V power supply (VCC=5V, GND connected to circuit ground).

[0044] Pin connections: The non-inverting input terminal (pin 3) of U1 is connected to the second-stage filter node of the signal conditioning module (receiving 0.84–5.26V DC signal) via a wire. The inverting input terminal (pin 2) of U1 is connected to the reference voltage divider circuit (R5=10kΩ, R6=10kΩ series voltage divider for 5V power supply, voltage divider point Vref=2.5V). The output terminal (pin 1) of U1 is connected to the non-inverting input terminal (pin 3) through a feedback resistor R7=100kΩ to form a hysteresis positive feedback; The output terminal (pin 1) of U1 is simultaneously connected to the input terminal of the monostable trigger module via a wire.

[0045] IV. Connection of the Monostable Trigger Module (555 Timer) Core component: NE555 timer (U2), 5V power supply (VCC=5V, GND connected to circuit ground).

[0046] Pin connections: The trigger terminal (pin 2) of U2 is connected to the output terminal (pin 1) of LM393 via a wire to receive the shaped square wave signal; The threshold terminal (pin 6) and discharge terminal (pin 7) of U2 are connected in parallel and then connected to VCC through a timing resistor R8 = 330kΩ; The threshold terminal (pin 6) of U2 is simultaneously connected to GND through a timing capacitor C3 = 1μF; The reset pin (pin 4) of U2 is directly connected to VCC (to disable reset); The output terminal (pin 3) of U2 is connected to the input terminal of the counter module via a wire.

[0047] Table 1 Summary of Key Connections V. Working Principle 1. 555 trigger pulse generation The gait sensor (liquid metal / PDMS porous sponge) outputs an alternating voltage signal under the pressure of the foot, which triggers a 555 monostable trigger after signal conditioning.

[0048] The 555 timer outputs a high-level pulse of fixed width (e.g., 363ms, determined by parameters R8=330kΩ and C3=1μF), which serves as the counting trigger signal for "one step".

[0049] 2. CD4026 Counting and Decoding Counting function: For each high-level pulse (rising edge triggered) received by the clock input terminal (CP, pin 1) of CD4026 from the output of 555, the internal counter increments by 1, and the count value cycles from 0→1→2→…→9 (decimal counting).

[0050] Decoding Function: The CD4026 has a built-in 7-segment decoder that converts the count value (0-9) into a 7-segment code signal (ag segment high and low level combination) in real time, which is output through pins 9-15. For example: When the count value is "0", outputs a, b, c, d, e, and f at high levels (g at low level), and the digital tube displays "0". When the count value is "1", outputs b and c are at high levels (the rest are low), and the digital tube displays "1".

[0051] 3. Digital tube display The ag segment pin of the common cathode seven-segment tube receives a high-level signal from the CD4026, and the corresponding segment lights up to intuitively display the current number of steps (0-9 cycle).

[0052] A current-limiting resistor (1kΩ) can be used to protect the CD4026 output pins and the segment selection LEDs of the digital tube to prevent them from burning out due to overcurrent.

[0053] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A step counting circuit module for a liquid metal / PDMS porous sponge pedometer sensor unit, characterized by, include: The signal conditioning unit is used to receive and process the alternating voltage signal generated by the gait sensing unit and output the shaped counting pulse. The counting and decoding unit has its input terminal connected to the output terminal of the signal conditioning unit and is used to count and decode the counting pulses. The display unit is connected to the output of the counting decoding unit and is used to display the count value; And a power supply unit, which supplies power to the signal conditioning unit, the counting and decoding unit and the display unit; The alternating voltage signal is stepped down before being acquired, and the counting and decoding unit uses a CD4026 chip to implement decimal counting and 7-segment code decoding.

2. The pedometer circuit module according to claim 1, characterized in that, The signal conditioning unit comprises, in sequence: A voltage divider circuit is used to divide the high-amplitude alternating voltage output by the gait sensing unit; A rectifier circuit, connected to the voltage divider circuit, is used to convert the divided alternating voltage into a unipolar pulse signal; A filtering circuit, connected to the rectifier circuit, is used to filter out noise in the unipolar pulse signal; and a waveform shaping circuit, connected to the filtering circuit, is used to shape the filtered signal into a square wave signal with steep edges, as the counting pulse.

3. The pedometer circuit module according to claim 2, characterized in that, The waveform shaping circuit is a Schmitt trigger, which includes an LM393 voltage comparator. The non-inverting input of the LM393 voltage comparator receives the filtered signal, the inverting input is connected to a reference voltage, and the output is connected to the non-inverting input through a feedback resistor to form positive feedback and generate a hysteresis effect.

4. A pedometer circuit module according to claim 2 or 3, characterized in that The signal conditioning unit further includes a monostable trigger circuit, the input of which is connected to the output of the waveform shaping circuit, for converting the square wave signal into a single pulse signal with a fixed pulse width, which is then used as the counting pulse input to the counting decoding unit.

5. The pedometer circuit module according to claim 4, characterized in that, The monostable trigger circuit is implemented using an NE555 timer. Its trigger terminal receives the square wave signal, and the fixed pulse width is determined by a timing resistor and a timing capacitor connected between its threshold terminal and discharge terminal.

6. The step counting circuit module of claim 1, wherein, The clock input terminal of the CD4026 chip receives the counting pulse, and its 7-segment output pin is connected to the display unit through a current-limiting resistor; the display enable pin of the CD4026 chip is connected to a high level, the clock disable pin is grounded, and the reset pin is connected to the power supply through a pull-up resistor.

7. The step counting circuit module according to claim 6, characterized in that, The display unit is a common cathode seven-segment display with its common terminal grounded, and its segment selection pin is connected to the 7-segment output pin of the CD4026 chip through the current limiting resistor.

8. The step counting circuit module according to claim 1, characterized in that, The power supply unit includes a voltage regulator chip, which converts the external input voltage into a stable 5V DC voltage to power the CD4026 chip, waveform shaping circuit and monostable trigger circuit.

9. The step counting circuit module according to claim 1, characterized in that, The step counting circuit module integrates a low-power management function, which controls the display enable pin level of the CD4026 chip to turn off the display unit in the idle state to reduce power consumption.

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