In traditional products, there are many places where water level detection is required, such as atomizers in home appliances. If there is no water, it is dry burning, which will damage the shock plate. The coffee machine needs to use water for brewing. The traditional solution is a contact solution. For example, a reed switch is placed inside the water tank to determine whether there is water through physical contact. Then, the water level detection based on the touch button can completely avoid physical contact, and only need to attach the touch panel to the outer wall of the water tank for sensing. This article explains the water level detection technology based on the ChipON touch button MCU from the principle of touch buttons and practical applications.

      ChipON's various touch-in-one MCUs embed the touch button Touch module as a peripheral into the MCU system. Combined with AD, PWM module, touch-in-one MCU improves system integration and facilitates user development and design. .

    1, touch button principle

The ChipON touch button technology is based on the principle of charge transfer. When a finger or other object with parasitic capacitance contacts the sensor (touch pad), the overall charge is increased, which speeds up the charge transfer. This will tell if there is a finger touch. ChipON applies this principle to water level detection technology. Because water and fingers are the same, it can also be regarded as an electrode. When water and sensor (touch pad) are separated by the cover, a simple parallel plate capacitor can be formed.

    2, system application design

The water_pad is used to close the outer wall of the water tank to detect the water level; the P12 port is used to access the reference capacitor of the touch button. K1 is used as the reference channel, and OUT1, OUT2, OUT3, and OUT4 are used as status outputs.

ChipON provides a dedicated library algorithm for touch level detection. The combination of the demo sample program and the algorithm library facilitates product development. For dedicated water level detection applications, only the channel needs to be configured, and the filter parameters and water change settings can be set to complete the detection of the water level channel. The output only needs to add a small amount of code to complete the output of the result.

    For products with functional applications, such as temperature sensing, switching IO, PWM output. Add the corresponding resource and control code to the demo.

         Demo provides code to support online observation of touch sample data, making it easy to use ChipONTSTool software for dynamic data observation and parameter setting.

    Note: The ChipON TSTool software is a touch button debugging software that allows users to visually view the current changes in touch sample values. Simple to use!