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.


System Overview

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.


Example: 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.

Recommended Products
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
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