Liquid Level Detection System Based on MSP430 CapTIvate Technology
Abstract
This application note introduces a system solution for liquid level detection using a capacitive touch MCU. It introduces the basic principles of capacitive touch to detect liquid level. Then it uses MSP430FR2533 capacitive touch MCU to design the system, finish the debugging of the software code, and verify the solution with a bench test. The test results show that the solution can accurately measure the depth of the liquid. Furthermore, four different electrode connection methods and two different capacitance measurement methods are tested and compared. Ultimately, it introduce a software optimization for the large error in small liquid heights.
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1 Introduction
In some application scenarios of capacitive touch, the customer might not want to use capacitive touch to detect whether the button is pressed, but instead they want to use the principle of capacitive touch to detect the depth of a liquid, such as the depth of the humidifier water tank or a vacuum robot water tank. To meet the needs of customers, this paper designs a liquid level detection system based on the MSP430FR2533 capacitive touch MCU, which can be simple, convenient and flexible for liquid depth measurement, and at the same time can achieve high accuracy water level measurement and low system cost. Figure 1-1 is a simplified schematic diagram of the liquid level detection system.
Figure 1-1 Simplified Schematic of Liquid Level Detection System