阅读说明：本技术 一种电感式全密封防爆键盘系统及使用方法 (Inductance type full-sealed explosion-proof keyboard system and use method ) 是由 吴开拓 李伟 龚天平 张毅 童赟 韩丹 于 2021-08-06 设计创作，主要内容包括：本发明公开一种电感式全密封防爆键盘系统,包括CPU及射频信号产生电路、谐振电容、电感线圈、采样电阻、有效值检波电路、ADC转换电路和接口电路；本发明还提供一种电感式全密封防爆键盘系统使用方法,包括以下步骤：电感线圈感应手指的触摸动作,在有手指的触摸时,电感线圈的电阻变化,生成手指触摸动作；有效值检波电路通过第一采样电阻R2检测到的直流电压发生变化；ADC转换电路将检测到的手指的触摸动作转化为手指的触摸信号发送给CPU及射频信号产生电路；CPU及射频信号产生电路根据手指的触摸信号生成响应的数字量发送给接口电路。本发明为一种用手指即可触摸感应的按键；该按键为全密封结构,尤其适用于防爆要求的场合。(The invention discloses an inductance type full-sealed explosion-proof keyboard system, which comprises a CPU (Central processing Unit), a radio-frequency signal generating circuit, a resonant capacitor, an inductance coil, a sampling resistor, an effective value detection circuit, an ADC (analog-to-digital converter) conversion circuit and an interface circuit, wherein the CPU is connected with the radio-frequency signal generating circuit; the invention also provides a use method of the inductance type fully-sealed explosion-proof keyboard system, which comprises the following steps: the inductive coil induces the touch action of the finger, and when the finger touches, the resistance of the inductive coil changes to generate the touch action of the finger; the effective value detection circuit detects that the direct-current voltage detected by the first sampling resistor R2 changes; the ADC conversion circuit converts the detected touch action of the finger into a touch signal of the finger and sends the touch signal to the CPU and the radio frequency signal generation circuit; the CPU and the radio frequency signal generating circuit generate a digital quantity of response according to the touch signal of the finger and send the digital quantity to the interface circuit. The invention relates to a key which can be touched and sensed by fingers; the key is of a full-sealing structure and is particularly suitable for occasions with explosion-proof requirements.)

1. The utility model provides an inductance type totally enclosed explosion-proof keyboard system which characterized in that: the device comprises a CPU (Central processing Unit), a radio frequency signal generating circuit (1), a resonant capacitor (2), an inductance coil (3), a sampling resistor (4), an effective value detection circuit (5), an ADC (analog to digital converter) circuit (6) and an interface circuit (7);

resonance capacitor (2) and inductance coil (3) are connected, and inductance coil (3) are connected with parallelly connected sampling resistance (4) and the effective value detection circuit (5) that set up, and parallelly connected sampling resistance (4) and the effective value detection circuit (5) that set up are connected with ADC converting circuit (6) and CPU and radio frequency signal generating circuit (1) in proper order, and CPU and radio frequency signal generating circuit (1) are connected with interface circuit (7) and resonance capacitor (2) respectively.

2. The inductive fully-sealed explosion-proof keyboard system according to claim 1, wherein:

the resonance capacitor (2) comprises a first resonance capacitor C1 and a second resonance capacitor C2;

the inductor coil (3) comprises a first inductor coil L1;

the sampling resistor (4) comprises a first sampling resistor R2;

one end of a CPU and radio frequency signal generating circuit (1) is connected with one end of a second resonant capacitor C2, the other end of the second resonant capacitor C2 is connected with one end of a first inductance coil L1, the other end of the first inductance coil L1 is connected with one end of a matching resistor R1, the other end of the matching resistor R1 is connected with an effective value detection circuit (5) and one end of a first sampling resistor R2 which are arranged in parallel, and the other ends of the effective value detection circuit (5) and the first sampling resistor R2 which are arranged in parallel are connected with the other end of the CPU and radio frequency signal generating circuit (1) after passing through an ADC conversion circuit (6); the first resonant capacitor C1 is connected in parallel to two ends of the first inductor L1 and the matching resistor R1 after being connected in series;

the CPU and the radio frequency signal generating circuit (1) are also connected with an interface circuit (7).

3. The inductive fully-sealed explosion-proof keyboard system according to claim 2, wherein:

the CPU and the radio frequency signal generating circuit (1) have three functions: firstly, generating an excitation signal of 0.5M-50 MHz; secondly, controlling an ADC (analog to digital converter) circuit (6) to convert the touch signal of the finger into a responding digital quantity; and thirdly, converting the coded value of the key into a current signal of 4-20 mA, wherein the current of 4-20 mA is used for identifying the key.

4. The inductive fully-sealed explosion-proof keyboard system according to claim 3, wherein:

the resonance capacitor (2) and the inductance coil (3) are used for sensing the touch action of a finger; when no touch action is performed, the touch action and the touch action are in a resonance state, and the sum of voltages applied to the touch action and the touch action is 0; when a finger approaches the inductance coil (3), the impedance of the inductance coil (3) changes, and the two are in a non-resonance state.

5. The inductive fully-sealed explosion-proof keyboard system according to claim 4, wherein:

the effective value detection circuit (5) is used for converting the alternating current radio frequency signal of the sampling resistor (4) into a direct current voltage signal which can be directly converted by the ADC conversion circuit (6);

the ADC conversion circuit (6) converts the touch action of the finger into a digital signal which can be recognized by the CPU and the radio frequency signal generation circuit (1) and is used as a touch signal of the finger; the finger touch action will result in a significant increase in ADC conversion results.

6. A method of using an inductive fully sealed explosion proof keyboard system according to any one of claims 1 to 5, comprising: the method comprises the following steps:

the inductive coil (3) induces the touch action of the finger, and when the finger touches, the resistance of the inductive coil (3) changes to generate the finger touch action; the direct-current voltage detected by the effective value detection circuit (5) through the first sampling resistor R2 changes;

the ADC conversion circuit (6) converts the detected touch action of the finger into a touch signal of the finger and sends the touch signal to the CPU and the radio frequency signal generation circuit (1);

the CPU and the radio frequency signal generating circuit (1) generate a digital quantity of response according to the touch signal of the finger and send the digital quantity to the interface circuit (7).

7. A method of using an inductive fully sealed explosion proof keyboard system according to any one of claims 1 to 5, comprising: the method comprises the following steps:

the resonant frequency of the first inductor L1 and the resonant circuit is expressed as follows:

Z₁+Z₂＝0

in the formula: z1 represents the impedance of the second resonant capacitor C2;

z2 represents the total impedance of the element matching resistor R1, the first resonant capacitor C1 and the first inductor L1;

ω represents the angular frequency, which can be calculated from the time frequency:

ω＝2πf₀

in the formula: f. of₀Represents a frequency;

then it can be calculated that the resonant frequency of the circuit is:

8. the use method of the inductive fully-sealed explosion-proof keyboard system according to claim 7, wherein:

taking C1 as 1pF and C2 as 8.2 pF; substituting the formula: at this time, the resonant frequency is f₀＝16.594MHz。

Technical Field

The invention relates to the field of explosion-proof equipment, in particular to an inductance type fully-sealed explosion-proof keyboard system and a using method thereof.

Background

Common inductance keys or capacitance keys on the market cannot meet application environments of oil depots, gas stations and the like. In addition, most of the inductive keys need to be equipped with a special touch pen for transmitting signals with a certain frequency, and the phenomenon that the keyboard cannot be used due to the loss of the touch pen often occurs.

Conventional metal keyboards have two disadvantages: firstly, at the temperature of minus 40 ℃, the elasticity of the rubber or silica gel elastic cushion can fail to cause key clamping stagnation; secondly, the lifetime is limited, and the elastic material loses its elasticity completely after about 50000 times.

After the explosion-proof glass is additionally arranged on the capacitive keyboard, the sensitivity is reduced and even the capacitive keyboard cannot be used.

Accordingly, there is a need for improvements in the art.

Disclosure of Invention

The invention aims to provide an efficient inductive fully-sealed explosion-proof keyboard system and a using method thereof.

In order to solve the technical problem, the invention discloses an inductance type fully-sealed explosion-proof keyboard system which comprises a CPU, a radio frequency signal generating circuit, a resonant capacitor, an inductance coil, a sampling resistor, an effective value detection circuit, an ADC (analog-to-digital converter) conversion circuit and an interface circuit, wherein the CPU is connected with the radio frequency signal generating circuit;

the resonance capacitor is connected with the inductance coil, the inductance coil is connected with the sampling resistor and the effective value detection circuit which are arranged in parallel, the sampling resistor and the effective value detection circuit which are arranged in parallel are sequentially connected with the ADC conversion circuit, the CPU and the radio frequency signal generation circuit, and the CPU and the radio frequency signal generation circuit are respectively connected with the interface circuit and the resonance capacitor.

As an improvement to the inductive fully-sealed explosion-proof keyboard system of the present invention:

the resonant capacitor comprises a first resonant capacitor C1 and a second resonant capacitor C2;

the inductor coil comprises a first inductor coil L1;

the sampling resistor comprises a first sampling resistor R2;

one end of a CPU and radio frequency signal generating circuit is connected with one end of a second resonant capacitor C2, the other end of the second resonant capacitor C2 is connected with one end of a first inductance coil L1, the other end of the first inductance coil L1 is connected with one end of a matching resistor R1, the other end of the matching resistor R1 is connected with an effective value detection circuit and one end of a first sampling resistor R2 which are arranged in parallel, and the other ends of the effective value detection circuit and the first sampling resistor R2 which are arranged in parallel are connected with the other ends of the CPU and radio frequency signal generating circuit after passing through an ADC (analog-to-digital converter); the first resonant capacitor C1 is connected in parallel to two ends of the first inductor L1 and the matching resistor R1 after being connected in series;

the CPU and the radio frequency signal generating circuit are also connected with the interface circuit.

As an improvement to the inductive fully-sealed explosion-proof keyboard system of the present invention:

the CPU and the radio frequency signal generating circuit have three functions: firstly, generating an excitation signal of 0.5M-50 MHz; secondly, controlling an ADC (analog to digital converter) conversion circuit to convert the touch signal of the finger into a response digital quantity; and thirdly, converting the coded value of the key into a current signal of 4-20 mA, wherein the current of 4-20 mA is used for identifying the key.

As an improvement to the inductive fully-sealed explosion-proof keyboard system of the present invention:

the resonance capacitor and the inductance coil are used for sensing the touch action of the finger; when no touch action is performed, the touch action and the touch action are in a resonance state, and the sum of voltages applied to the touch action and the touch action is 0; when a finger approaches the inductor, the impedance of the inductor changes, and the inductor are in a non-resonant state.

As an improvement to the inductive fully-sealed explosion-proof keyboard system of the present invention:

the effective value detection circuit is used for converting the alternating current radio frequency signal of the sampling resistor into a direct current voltage signal which can be directly converted by the ADC conversion circuit;

the ADC conversion circuit converts the touch action of the finger into a digital signal which can be recognized by the CPU and the radio frequency signal generation circuit and is used as a touch signal of the finger; the finger touch action will result in a significant increase in ADC conversion results.

The invention also provides a use method of the inductance type fully-sealed explosion-proof keyboard system, which comprises the following steps:

the inductive coil induces the touch action of the finger, and when the finger touches, the resistance of the inductive coil changes to generate the touch action of the finger; the effective value detection circuit detects that the direct-current voltage detected by the first sampling resistor R2 changes;

the ADC conversion circuit converts the detected touch action of the finger into a touch signal of the finger and sends the touch signal to the CPU and the radio frequency signal generation circuit;

the CPU and the radio frequency signal generating circuit generate a digital quantity of response according to the touch signal of the finger and send the digital quantity to the interface circuit.

The invention also provides a use method of the inductance type fully-sealed explosion-proof keyboard system, which comprises the following steps:

the resonant frequency of the first inductor L1 and the resonant circuit is expressed as follows:

Z₁+Z₂＝0

in the formula: z1 represents the impedance of the second resonant capacitor C2;

z2 represents the total impedance of the element matching resistor R1, the first resonant capacitor C1 and the first inductor L1;

ω represents the angular frequency, which can be calculated from the time frequency:

ω＝2πf₀

in the formula: f. of₀Represents a frequency;

then it can be calculated that the resonant frequency of the circuit is:

as an improvement to the use method of the inductance type fully-sealed explosion-proof keyboard system of the invention:

taking C1 as 1pF and C2 as 8.2 pF; substituting the formula: at this time, the resonant frequency is f₀＝16.594MHz。

The inductance type full-sealed explosion-proof keyboard system has the technical advantages that:

the invention relates to a key which can be touched and sensed by fingers; the key is a full-sealing structure. In addition, the button can output 4-20 mA signals, and is particularly suitable for occasions with explosion-proof requirements.

The invention directly adopts the mature ARM processor technology, directly generates the 0.5M-50 MHz excitation signal by the singlechip (the CPU and the radio frequency signal generating circuit), does not need an additional signal source, thereby reducing the circuit complexity and saving the cost;

the invention adopts mature circuit board and micro-coil processing technology to ensure that the quality factor of the first inductance coil L1 is between 15 and 90, and the quality factor is an optimal value (the quality factor is too low, the voltage change is not obvious when a finger approaches a key, and the dry and wet state of the finger can cause wrong key identification if the quality factor is too high).

The service life of the inductive keyboard of the invention is close to infinite times: because no touch occurs, there is no problem of mechanical wear or material fatigue. The inductive keyboard of the invention has long sensing distance: the key can be detected even if glass with the thickness of 5mm is added.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

FIG. 1 is a block schematic diagram of an inductive fully-enclosed explosion-proof keyboard system of the present invention;

FIG. 2 is a schematic circuit diagram of an inductive fully-enclosed explosion-proof keyboard system of the present invention.

Detailed Description

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.

Embodiment 1, an inductance type fully-sealed explosion-proof keyboard system, as shown in fig. 1-2, includes a CPU and radio frequency signal generating circuit 1, a resonant capacitor 2, an inductance coil 3, a sampling resistor 4, an effective value detecting circuit 5, an ADC converting circuit 6, and an interface circuit 7.

The resonant capacitor 2 is connected with the inductance coil 3, the inductance coil 3 is connected with the sampling resistor 4 and the effective value detection circuit 5 which are arranged in parallel, the sampling resistor 4 and the effective value detection circuit 5 which are arranged in parallel are sequentially connected with the ADC conversion circuit 6, the CPU and the radio frequency signal generating circuit 1, and the CPU and the radio frequency signal generating circuit 1 are respectively connected with the interface circuit 7 and the resonant capacitor 2.

The resonant capacitor 2 comprises a first resonant capacitor C1 and a second resonant capacitor C2;

the inductor coil 3 includes a first inductor coil L1;

the sampling resistor 4 comprises a first sampling resistor R2;

the specific connection relationship is as follows: one end of the CPU and radio frequency signal generating circuit 1 is connected with one end of a second resonance capacitor C2, the other end of the second resonance capacitor C2 is connected with one end of a first inductance coil L1, the other end of the first inductance coil L1 is connected with one end of a matching resistor R1, the other end of the matching resistor R1 is connected with one end of an effective value detection circuit 5 and one end of a first sampling resistor R2 which are arranged in parallel, and the other ends of the effective value detection circuit 5 and the first sampling resistor R2 which are arranged in parallel are connected with the other end of the CPU and radio frequency signal generating circuit 1 after passing through an ADC conversion circuit 6. The first resonant capacitor C1 is connected in parallel to the two ends of the first inductor L1 and the matching resistor R1 after they are connected in series.

The CPU and the radio frequency signal generating circuit 1 are also connected with an interface circuit 7.

The matching resistor R1 is used to adjust the quality factor.

The CPU and rf signal generating circuit 1 has three functions: firstly, generating an excitation signal (voltage and the like are unchanged) of 0.5M-50 MHz; secondly, controlling the ADC conversion circuit 6 to convert the touch signal of the finger into a response digital quantity (namely, a coded value of the key); and thirdly, converting the coded values of the keys into current signals of 4-20 mA, wherein the currents of 4-20 mA are used for identifying which key is pressed (for example, 4mA represents that a number 1 on the keyboard is pressed, 5mA represents that a number 2 on the keyboard is pressed, and the like).

In the invention, each key corresponds to one first inductance coil L1, and the coded value of each key is converted into different current signals.

The resonant capacitor 2 and the inductance coil 3 are used for sensing the touch action of the finger. When there is no touch, the two are in resonance, and the sum of the voltages applied to the two is 0. When a finger approaches the inductor 3 (i.e. there is a touch), the impedance of the inductor 3 changes, and the two are in a non-resonant state.

The sampling resistor 4 is used to identify whether a touch action has occurred. In the resonance state, the voltage across the sampling resistor 4 is 0.7Vcc or more (i.e., if the power supply is 5V, the voltage across the sampling resistor 4 is 3.5V or more); in the non-resonant state (no finger touch), the voltage across the sampling resistor 4 is 0.2Vcc or less (i.e., if the power supply is 5V, the voltage across the sampling resistor 4 is 1.0V or less).

The effective value detection circuit 5 is used for converting the alternating current radio frequency signal of the sampling resistor 4 into a direct current voltage signal which can be directly converted by the ADC conversion circuit 6.

The ADC conversion circuit 6 converts the touch action of the finger into a digital signal that can be recognized by the CPU and the rf signal generation circuit 1 as a touch signal of the finger. The finger touch action will result in a significant increase in ADC conversion results.

The 4-20 mA interface circuit 7 is used for a special interface in an explosion-proof occasion.

The invention provides a using method of an inductance type fully-sealed explosion-proof keyboard, which comprises the following steps:

the first inductance coil L1 senses a touch action of a finger, and when the finger touches the first inductance coil L1, the resistance of the first inductance coil L3578 changes to generate the finger touch action; the dc voltage detected by the effective value detection circuit 5 through the first sampling resistor R2 changes;

the ADC conversion circuit 6 converts the detected touch action of the finger into a touch signal of the finger and sends the touch signal to the CPU and the radio frequency signal generation circuit 1;

the CPU and rf signal generating circuit 1 generates a digital quantity of response according to the touch signal of the finger and sends the digital quantity to the interface circuit 7.

The first inductor L1 and the resonant circuit are implemented as shown in fig. 2:

the resonant frequency formula is as follows:

Z₁+Z₂＝0

in the formula: z1 represents the impedance of the second resonant capacitor C2;

z2 represents the total impedance of the element matching resistor R1, the first resonant capacitor C1 and the first inductor L1;

ω represents angular frequency, which can be calculated from time frequency;

ω＝2πf₀

f₀represents a frequency;

to facilitate the engineering realization, take C₂＝8.2C₁8.2C; and C is an international standard series capacitance value. All the devices are standardized during mass production, for example, capacitance values of two capacitors (a first resonant capacitor C1 and a second resonant capacitor C2) are respectively 1 picofarad and 8.2 picofarads (the two components are standard components and do not need to be customized by a manufacturer).

Then it can be calculated that the resonant frequency of the circuit is:

c1 ═ 1pF, C2 ═ 8.2 pF; substituting the formula: at this time, the resonant frequency is f₀＝16.594MHz。

Finally, it is also noted that the above-mentioned lists merely illustrate a few specific embodiments of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.