Easy, Cost-Effective Liquid and Solid Material Detection Solution
Renesas' Material Detection Solution can detect materials or liquids without external sensors by using microcontrollers (MCUs) with a built-in capacitive touch sensor unit (CTSU). This solution has application examples in a wide variety of fields.
Here is an overview of the detection performed by this solution.
As shown in figures 1 and 2, this solution connects two thin-film electrodes (a transmitting electrode and a receiving electrode) and measures the capacitance between those electrodes using the CTSU of one of its MCUs. Changes in the measured materials are determined by detecting the change in capacitance between the electrodes.
Three-stage detection (one transmitting electrode and three receiving electrodes)
From Figure 1 to Figure 2, the capacitance between the electrodes changes as the amount of material between the electrodes decreases.
In Figure 2, the capacitance between the transmitting electrode and the top and middle receiving electrodes has decreased, and the capacitance of the bottom receiving electrode is unchanged.
By measuring the capacitance between each electrode, the MCU can determine that the materials are positioned at one of the three stages.
|Group||Flash (KB)||RAM (KB)||Pin Count||Operating Voltage (V)||Frequency (MHz)||CTSU (Channels)||Communication|
|RX113||128-512||32-64||64-100||1.8 to 3.6||32||12||USB, IIC, SCI, SPI, SSI,|
|RX130||64-512||10-48||48-100||1.8 to 5.5||32||24-36||IIC, SCI, SPI, EMC|
|RX230, RX231||128-512||32-64||48-100||1.8 to 5.5||54||6-24||USB, IIC, SCI, SPI, CAN, SDHI, SSI|
|Hardware related information|
|RX130 Water level detection board sample schmatic (PDF)|
|RX130 Electrode sample (PDF) (container thickness: 1mm or less)|
|Software related information|
|RX130 Water level detection sample code (ZIP)|
Related Technology and Development Tools
Capacitive touch technology can provide an intuitive user interface, allowing features such as an overlay to be manipulated with the touch of a finger or a quantity to be selected with a swipe motion. Renesas offers several solutions that help in the development of touch systems.
This development assistance tool supports Renesas' RX 32-bit MCUs and RA 32-bit MCUs in the development of embedded systems that use capacitive touch sensors. The tool simplifies development by letting users easily adjust the sensitivity of touch sensors, previously a complex task, and control system operation.
Workbench6, the integrated development environment (IDE) used with Renesas RX 32-bit microcontrollers for capacitive touch applications, allows for easy adjustments with a wizard format, simple operations using an intuitive user interface, and automatically adjusted source code as outputs.