CN111796208A - Keyboard open-short circuit detection device and method - Google Patents
Keyboard open-short circuit detection device and method Download PDFInfo
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- CN111796208A CN111796208A CN202010764804.4A CN202010764804A CN111796208A CN 111796208 A CN111796208 A CN 111796208A CN 202010764804 A CN202010764804 A CN 202010764804A CN 111796208 A CN111796208 A CN 111796208A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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Abstract
The invention provides the keyboard open-short circuit detection device and the open-short circuit detection method which have the advantages of small volume, low cost, quick and convenient test and capability of ensuring the test precision. The device comprises an MCU (1), a key interface circuit (2), an ADC voltage sampling circuit (3) and an open-short circuit detection circuit (4), wherein the MCU completes resource calling and allocation of a hardware layer, processes voltage data acquired by the ADC voltage sampling circuit and communicates with an upper computer at the same time, the key interface circuit is used for accessing a key loop of a keyboard to be detected, the ADC voltage sampling circuit is used for acquiring open-short circuit voltage data of the key loop of the keyboard to be detected and transmitting the open-short circuit voltage data to the MCU, the open-short circuit detection circuit provides a plurality of open-short circuit test channels, and carries out level pull-up and pull-down on keys on each channel to carry out open-short circuit detection on the keys of the keyboard; the method comprises the following steps: and detecting open circuit and short circuit. The invention can be applied to the detection field.
Description
Technical Field
The invention relates to the field of detection, in particular to a keyboard open-short circuit detection device and method.
Background
The conventional matrix keyboard has the conditions of short circuit (dead key), open circuit of keys, short circuit of lines, open circuit and the like in the production process. The reason is that the conventional keyboard is composed of a circuit board, keys and a matrix output interface FPC (flexible circuit board), and the three parts (as shown in figure 1) have a certain probability of open short circuit in the production process, thereby causing the open short circuit of the whole keyboard.
The existing detection mode is that the short circuit is measured by connecting an ohmic gear of a multimeter from a keyboard interface end, only one loop can be measured at one time because the multimeter only has one pair of meter pens, and the loop on the keyboard is sequentially switched and connected to the multimeter in a group by using a relay board to measure the whole keyboard. The multimeter judges whether the keyboard has an open short circuit or not through the measured resistance value. This kind of mode can measure through the universal meter and open the short circuit to judge the quality of keyboard. However, the result is not intuitive, the measured resistance value needs to be analyzed under other conditions to judge the result, and the multimeter for data acquisition is expensive and large in size, so that inconvenience is increased in industrial production test.
The prior art has the following defects: 1. the short circuit of the keyboard is detected by using the ohmic gear of the multimeter, so that the time is long, the volume is large, and the cost is high; 2. the testing channel is switched by a relay, so that the speed is low; 3. the result can be obtained only by analyzing and judging the measured resistance value by additional software, which is not direct. In order to overcome the above disadvantages, a keyboard open/short circuit detection device with low cost, rapid and convenient test and capability of ensuring the test precision needs to be designed.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a keyboard open-short circuit detection device which is small in size, low in cost, quick and convenient in test and capable of ensuring the test precision, and a method for detecting the open-short circuit of a keyboard by using the device.
The technical scheme adopted by the keyboard open-short circuit detection device is as follows: the device of the invention comprises an MCU, a key interface circuit, an ADC voltage sampling circuit and an open-short circuit detection circuit,
the MCU completes resource calling and allocation of a hardware layer, processes voltage data acquired by the ADC voltage sampling circuit, and communicates with an upper computer;
the key interface circuit is used for accessing a key loop of the keyboard to be tested;
the ADC voltage sampling circuit is used for collecting open short-circuit voltage data of a keyboard key loop to be tested and transmitting the data to the MCU;
the open-short circuit detection circuit provides a plurality of open-short circuit test channels, and performs level pull-up and pull-down on the keys on each channel to perform open-short circuit detection on the keys of the keyboard.
The technical scheme is that the open-short circuit detection device is established by the MCU, the key interface circuit, the ADC voltage sampling circuit and the open-short circuit detection circuit, the keyboard keys to be detected are conveniently accessed by the key interface circuit, the MCU is used for realizing the rapid automatic switching control of different key detections, the open-short circuit detection circuit provides a plurality of open-short circuit detection channels, the keys on each channel are subjected to level pull-up and pull-down, the ADC voltage sampling circuit is used for collecting level values of sampling points, and the open-short circuit condition of the keyboard key loop to be detected can be judged through level value change; through the rapid automatic switching control of the MCU, the rapid switching of the key detection channels is realized, the detection efficiency is improved, and the phenomenon of low efficiency caused by the original adoption of a relay to switch the test channels is avoided; in addition, the MCU is used for analyzing the level change of the sampling points and further judging the open short circuit condition of the keyboard key loop to be detected, so that the detection precision is ensured, and the detection result error caused by the influence of human factors is avoided.
Further, the open short detection circuit provides 32 open short test channels. Therefore, the keyboard key detection method and the keyboard key detection device can detect a plurality of keyboard keys at the same time, and greatly improve the test efficiency.
Still further, open short-circuit detection circuitry comprises first analog switch, second analog switch, third analog switch and fourth analog switch, first analog switch with the second analog switch constitutes 16 way test channels jointly, third analog switch with the fourth analog switch constitutes 16 other way test channels jointly, key interface circuit connects gradually first analog switch with the second analog switch and the third analog switch with the passageway department that the fourth analog switch constitutes. Therefore, the test channel is established by the four analog switches, and the analog switches can realize the pull-up or pull-down control on the level of the test loop quickly, so that the detection efficiency and accuracy are further improved.
In addition, the ADC voltage sampling circuit is arranged in the MCU, the ADC voltage sampling circuit comprises an ADC module and a buffer circuit, and the buffer circuit consists of a differential amplifier. Therefore, the buffer circuit can play a role in buffer protection on the MCU, and the damage of the MCU is avoided.
Further, the MCU is selected from the model STM32F407VET 6. The single chip microcomputer of the type is selected, so that the reliability and the stability of the device can be guaranteed, and the smooth proceeding of the detection process is guaranteed.
The method for detecting the open circuit and the short circuit of the keyboard by using the device for detecting the open circuit and the short circuit of the keyboard is characterized by comprising the following steps of:
a. an open circuit detection step:
the method comprises the steps that a keyboard key to be tested is connected into a key interface circuit, when the key is not pressed, the sampling point of an ADC voltage sampling circuit is set to be a high level, after the key is pressed, the sampling point of the ADC voltage sampling circuit is changed into a low level, at the moment, each key of the keyboard to be tested is enabled in sequence, meanwhile, a MCU collects the level change of the collection point of the ADC voltage sampling circuit in real time, and then whether the level of the collection point changes according to a set mode or not is analyzed, and then whether an open circuit exists in a keyboard key loop is judged;
b. short circuit detection:
the keyboard key to be tested is connected into the key interface circuit, the sampling point of the ADC voltage sampling circuit is set to be a high level when the keyboard is not in a short-circuit state, after a short circuit occurs, the sampling point of the ADC voltage sampling circuit is changed into a low level, each key of the keyboard to be tested is switched in sequence, meanwhile, the MCU collects the level change of the collection point of the ADC voltage sampling circuit in real time, and then whether the level of the collection point changes according to a set mode or not is analyzed, and then whether a short circuit exists in a keyboard key loop or not is judged.
Above-mentioned scheme is visible, utilizes MCU to carry out passageway switching control and sampling point level change analysis, can ensure the quick convenience and the reliable stability that the device detected, and the testing process is simple, utilizes MCU to realize the switching of the keyboard button return circuit that the integral type awaits measuring and opens the short circuit and detect, and the cost is reduced has also reduced the volume of device, has avoided the intervention of artificial factor simultaneously, has guaranteed the accuracy that detects.
Drawings
FIG. 1 is a schematic diagram of a keyboard key circuit;
FIG. 2 is a simplified schematic of the system of the present invention;
FIG. 3 is a schematic circuit diagram of the open circuit detection of the present invention;
FIG. 4 is a schematic diagram of the electrical circuit for short circuit detection of the present invention;
FIG. 5 is a circuit schematic of the MCU;
FIG. 6 is a schematic diagram of the buffer circuit;
FIG. 7 is a schematic diagram of the key interface circuit;
fig. 8 is a schematic diagram of the open short detection circuit.
Detailed Description
As shown in fig. 1 to 8, the detection device of the present invention comprises an MCU 1, a key interface circuit 2, an ADC voltage sampling circuit 3, and an open short circuit detection circuit 4, wherein the MCU 1 is selected from the model STM32F407VET6,
the MCU 1 completes resource calling and allocation of a hardware layer, processes voltage data collected by the ADC voltage sampling circuit 3, and communicates with an upper computer;
the key interface circuit 2 is used for accessing a key loop of a keyboard to be tested;
the ADC voltage sampling circuit 3 is used for collecting open short-circuit voltage data of a keyboard key loop to be tested and transmitting the data to the MCU 1;
the open-short circuit detection circuit 4 provides a plurality of open-short circuit test channels, and performs level pull-up and pull-down on the keys on each channel to perform open-short circuit detection on the keys of the keyboard.
Specifically, the open short detection circuit 4 provides 32 open short test channels. Open short circuit detection circuitry 4 comprises first analog switch U9, second analog switch U10, third analog switch U12 and fourth analog switch U13, first analog switch U9 with second analog switch U10 constitutes 16 way test channels jointly, third analog switch U12 with fourth analog switch U13 constitutes 16 other way test channels jointly, key interface circuit 2 connects gradually first analog switch U9 with second analog switch U10 and third analog switch U12 with the passageway department that fourth analog switch U13 constitutes. The ADC voltage sampling circuit 3 is arranged in the MCU 1, the ADC voltage sampling circuit 3 comprises an ADC module and a buffer circuit, and the buffer circuit is composed of a differential amplifier.
The method for detecting the open circuit and the short circuit of the keyboard by using the device for detecting the open circuit and the short circuit of the keyboard comprises the steps of open circuit detection and short circuit detection, and specifically comprises the following steps:
a. an open circuit detection step:
the method comprises the steps that a keyboard key to be tested is connected into a key interface circuit, when the key is not pressed, the sampling point of an ADC voltage sampling circuit is set to be a high level, after the key is pressed, the sampling point of the ADC voltage sampling circuit is changed into a low level, at the moment, each key of the keyboard to be tested is enabled in sequence, meanwhile, a MCU collects the level change of the collection point of the ADC voltage sampling circuit in real time, and then whether the level of the collection point changes according to a set mode or not is analyzed, and then whether an open circuit exists in a keyboard key loop is judged;
b. short circuit detection:
the keyboard key to be tested is connected into the key interface circuit, the sampling point of the ADC voltage sampling circuit is set to be a high level when the keyboard is not in a short-circuit state, after a short circuit occurs, the sampling point of the ADC voltage sampling circuit is changed into a low level, each key of the keyboard to be tested is switched in sequence, meanwhile, the MCU collects the level change of the collection point of the ADC voltage sampling circuit in real time, and then whether the level of the collection point changes according to a set mode or not is analyzed, and then whether a short circuit exists in a keyboard key loop or not is judged.
Compared with the prior art, the invention can increase or reduce the test channels aiming at different matrix keyboards, thereby saving the cost; the keyboard open-short circuit condition is detected fully automatically, the testing system can automatically judge whether the keyboard is qualified or not, the structure is simple, the size is small, the movement is convenient, and manual misjudgment and cost are reduced.
Claims (6)
1. A keyboard opens short-circuit detection device which characterized in that: the detection device comprises an MCU (1), a key interface circuit (2), an ADC voltage sampling circuit (3) and an open-short circuit detection circuit (4),
the MCU (1) completes resource calling and allocation of a hardware layer, processes voltage data acquired by the ADC voltage sampling circuit (3), and communicates with an upper computer;
the key interface circuit (2) is used for accessing a key loop of a keyboard to be tested;
the ADC voltage sampling circuit (3) is used for collecting open short-circuit voltage data of a keyboard key loop to be tested and transmitting the data to the MCU (1);
the open-short circuit detection circuit (4) provides a plurality of open-short circuit test channels, and performs level pull-up and pull-down on the keys on each channel to perform open-short circuit detection on the keys of the keyboard.
2. The keyboard open/short circuit detection device according to claim 1, wherein: the open short detection circuit (4) provides 32 open short test channels.
3. The keyboard open/short circuit detection device according to claim 2, wherein: open short circuit detection circuitry (4) comprises first analog switch (U9), second analog switch (U10), third analog switch (U12) and fourth analog switch (U13), first analog switch (U9) with second analog switch (U10) constitutes 16 way test channels jointly, third analog switch (U12) with fourth analog switch (U13) constitutes 16 other way test channels jointly, key interface circuit (2) connect gradually first analog switch (U9) with second analog switch (U10) and third analog switch (U12) with the passageway department that fourth analog switch (U13) constitutes.
4. The keyboard open/short circuit detection device according to claim 1, wherein: the ADC voltage sampling circuit (3) is arranged in the MCU (1) in a built-in mode, the ADC voltage sampling circuit (3) comprises an ADC module and a buffer circuit, and the buffer circuit is composed of a differential amplifier.
5. The keyboard open/short circuit detection device according to claim 1, wherein: the MCU (1) is selected from STM32F407VET 6.
6. A method for detecting open/short of a keyboard using the keyboard open/short detection device of claim 3, the method comprising the steps of:
a. an open circuit detection step:
the method comprises the steps that a keyboard key to be tested is connected into a key interface circuit (2), when the key is not pressed down, the sampling point of an ADC voltage sampling circuit (3) is set to be a high level, after the key is pressed down, the sampling point of the ADC voltage sampling circuit (3) is changed into a low level, at the moment, each key of the keyboard to be tested is enabled in sequence, meanwhile, a MCU (1) collects the level change of a collection point of the ADC voltage sampling circuit (3) in real time, and then whether the level of the collection point changes according to a set mode or not is analyzed, and then whether an open circuit exists in a keyboard key loop is judged;
b. short circuit detection:
the keyboard key to be tested is connected into the key interface circuit (2), the sampling point of the ADC voltage sampling circuit (3) is set to be a high level when the keyboard is in a non-short-circuit state, after a short circuit is generated, the sampling point of the ADC voltage sampling circuit (3) is changed into a low level, each key of the keyboard to be tested is switched in sequence, meanwhile, the MCU (1) collects the level change of the collection point of the ADC voltage sampling circuit (3) in real time, and then analyzes whether the level of the collection point changes according to a set mode or not, so that whether a short circuit exists in a keyboard key loop or not is judged.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010764804.4A CN111796208A (en) | 2020-08-03 | 2020-08-03 | Keyboard open-short circuit detection device and method |
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| CN202010764804.4A CN111796208A (en) | 2020-08-03 | 2020-08-03 | Keyboard open-short circuit detection device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116381451A (en) * | 2023-03-03 | 2023-07-04 | 珠海芯烨电子科技有限公司 | Testing device and method for welding open-circuit single-ended planting needle based on thermosensitive piece |
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2020
- 2020-08-03 CN CN202010764804.4A patent/CN111796208A/en active Pending
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