Capacitor induction type touch press-key based on MCU and measuring method for touch press-key capacitance

A technology of capacitive sensing and measuring method, which is applied to measuring devices, measuring electrical variables, measuring resistance/reactance/impedance, etc., can solve the problems of large error in output signal value, easy wear of mechanical keys, misoperation or immobility, etc. Improve reliability, low cost, and achieve the effect of accurate positioning

Inactive Publication Date: 2009-08-05
LIERDA SCI & TECH GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, traditional mechanical buttons have the disadvantages of easy wear, complicated installation, and large changes due to environmental factors such as temperature, humidity, and dust; and piezoelectric thin-grinding touch buttons are not only expensive, but also easy to damage, and are affected by temperature and humidity. , the value error of its output signal is large, which is easy to cause misoperation or immobility

Method used

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  • Capacitor induction type touch press-key based on MCU and measuring method for touch press-key capacitance
  • Capacitor induction type touch press-key based on MCU and measuring method for touch press-key capacitance
  • Capacitor induction type touch press-key based on MCU and measuring method for touch press-key capacitance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Example 1: refer to the attached figure 1 . Based on the MCU-based capacitive sensing touch keys, the touch keys are distributed on the PCB printed circuit and are respectively connected to the I / O port of the MCU and one end of the resistor R. Touch keys, MCU I / O ports and resistors are 1 to n and are as attached. figure 1 shown in one-to-one correspondence.

Embodiment 2

[0012] Example 2: refer to the attached figure 2 . 1 to n touch keys are distributed on the PCB printed circuit and are connected with 1 to n I / O ports of the MCU respectively by wires, and a resistor R is used to connect the two touch keys. 1 to n I / O ports are high level, low level, high level, low level...and matched in pairs.

Embodiment 3

[0013] Embodiment 3: On the basis of Embodiments 1 and 2, based on the capacitive sensing touch button of MCU and the measurement method of the capacitance of the touch button, 1 to n I / O port pairs of the MCU are distributed on the PCB printed circuit. The capacitance of the touch button Charge or discharge, when no finger is pressed, the PCB touch button has a basic capacitor, and the MCU records the charge and discharge time for charging or discharging the basic capacitor to a certain voltage. When the finger is pressed on the PCB touch button, the MCU detects the charge and discharge When the time change reaches a certain threshold, the MCU judges that a key is pressed and calculates the key value.

[0014] The formula for calculating capacitor charging is:

[0015] U C = E * ( 1 - exp ( - t ...

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Abstract

The invention relates to a capacitive sensitive type touch key based on MCU and a measuring method for the capacitance of the touch key. The touch keys are distributed on a PCB printed circuit and are respectively connected with an I/O end of the MCU and one end of a resistor R and the other end of the resistor R is connected with the ground. The invention has the advantages that (1) the capacitance touch sensitive technology is adopted to design the touch keys, the cost is low and the special sensor is not needed; (2) the power consumption is lower; (3) the sensitive type light touch can realize the output of the signals; (4) the realizing mode can be diverse and can realize positioning of precision; (5) the touch key can replace various mechanical keys, switches and proximity detectors; (6) the structure is simple and the wear resistance is good; and (7) as the traditional key is not used, the touch sensitive key can adopt a whole seamless panel, the dust prevention effect is excellent and the reliability of the product is improved.

Description

technical field [0001] The invention relates to an MCU-based capacitive sensing touch key and a method for measuring the capacitance of the touch key, which are mainly used for electronic product control and belong to the field of touch key manufacturing. Background technique [0002] At present, traditional mechanical buttons have the disadvantages of easy wear and tear, complicated installation, and large changes due to environmental factors such as temperature, humidity and dust. Piezoelectric thin-grinding touch buttons are not only expensive, but also easy to damage, and are affected by temperature and humidity. , the value error of the output signal is large, and it is easy to cause misoperation or immobility. SUMMARY OF THE INVENTION [0003] Design purpose: In order to avoid the deficiencies in the background technology, a MCU-based capacitive sensing touch button and a method for measuring the capacitance of the touch button are designed using a PCB printed circui...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03K17/96G01R27/26
Inventor 何佳王鲁克梁源贾灵张其华祝继华张冲赵振东
Owner LIERDA SCI & TECH GRP
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