Because the washing machine is usually placed in a location where stains, dust, and water contamination are concentrated, the user needs to clean the surface of the washing machine frequently. During the cleaning process, it is found that the touch keys are easily damaged or water enters, causing the touch keys to fail. The touch screen senses the touch of a finger because when a finger touches a specific location on the screen, it sends a precise electronic signal to the screen.
Resistive touch buttons and capacitive sensing buttons. The principle of capacitive touch buttons is that a finger touch will have a certain induction to the current, so that the washing machine can be operated. To put it simply, when the human body is close to the capacitive button, the current generated by the human body is coupled to the static capacitance, and the capacitance value of the connection reaches the maximum, and the changing capacitance value at this time will transmit and transform the signal. , so that the capacitance signal is converted into a certain control signal, so as to achieve the function of controlling the washing machine.
The working principle of the resistance type is to use the human body to press the resistance, causing the resistance to change. The change of resistance will cause the whole circuit signal to change, so as to achieve the effect of controlling the smartphone. But his shortcomings are very big, the pressure must be to a certain extent, otherwise it will not be able to achieve its purpose, which is also a major disadvantage of resistive touch buttons.
The touch detection IC is a touch chip designed using the capacitive sensing principle. This chip has a built-in voltage regulator circuit for touch sensors. The stable touch effect can be applied to various applications. The human touch panel can be connected through non-conductive insulating materials. The main application is to replace mechanical switches or buttons. This chip can Independently supports 8 touch keys.
There is a capacitive touch chip from Korea GreenChip with 8 touch keys, which is represented by Gongcai.com. The capacitive touch chip - GT308L, GT308L provides 8 LED drivers and a 16-step dimming controller. OUT1~8 pins can be used for PWM output for LED dimming control. This is a very economical solution when LED feedback is required because there is no additional material cost for LED control. For touch output results, it can be used through I2C or 1:1 direct output interface implementation. The I2C interface may be useful for MCU IO or insufficient connector resources in the application.
GT308L can be applied to a wide supply voltage range of 2.5v to 5.5v. It has CTRL pins to select sensitivity options and I2C bus slave address by making pins connected to VDD, GND and open. The application will be more robust and problem-free with EMC, EMI, H/W variation, voltage disturbance, temperature drift, humidity drift, etc. In particular, it does not create any problems in CS and EFT noise environments that occur in any touch application.
