Liquid/Solid Material Detection for Industrial Applications


Capacitors, Microcontrollers (MCUs)

@RenesasAmerica #materialdetection #industrial #psd

High-Sensitivity Touch Key MCUs Measure the Capacitance Between Two Electrodes, Replacing Sensors

TOKYO, Japan – Renesas Electronics Corporation introduced its Material Detection Solution, which can detect materials or liquids easily and cost effectively without sensors by connecting electrodes using Renesas' RX130 capacitive touch-key microcontrollers (MCUs). Replacing the sensors with this electrode approach contributes to lower bill of materials (BOM) costs while enabling detection at multiple points using a single chip. This allows industrial equipment, OA equipment, and home appliance manufacturers to explore detection systems for cost-constrained applications.

Renesas’ touch-key MCUs feature a capacitive touch sensor unit specialized for capacitance measurement with extremely high sensitivity and high noise resistance. This enables the Material Detection Solution to easily detect the presence or absence of a powder such as vacuum cleaner dust, a liquid such as refrigerator and coffee maker, or material such as paper by measuring the capacitance between electrodes to the MCU. The increase or decrease of the powder, liquid, or material will change the capacitance value between the electrodes.

As sensor-based technology proliferates in industrial equipment, OA equipment, and home appliances, the demand for different types of sensor solutions is rapidly increasing to address diverse sensing needs. Applications require fine-grained sensing for predictive maintenance capabilities. For instance, printers are required to detect the remaining amounts of consumable materials and inform users in advance when replacements are required. Vacuum cleaners also need to manage the accumulation of dust retained by vacuum cleaner filters in order to perform efficient cleaning. This provides improved device functionality and increased user convenience.

Although these applications can be implemented by using various types of sensors, such as pressure sensors for detecting physical objects, photosensors, IR sensors, and CMOS sensors, the use of multiple sensors creates additional cost and heavy development burdens.

Key Features of the Material Detection Solution:

To achieve sensor-less physical object detection easily and cost-effectively, the Renesas solution connects two thin-film electrodes and measures the capacitance between those electrodes using one of its touch-key MCUs. Changes in the measured materials are determined by detecting the change in capacitance between the electrodes.

In addition to eliminating the need for sensor evaluation and operating condition determination, the initialization and sensitivity adjustments can be easily performed using the development support graphical user interface (GUI) tool available for capacitive touch sensor systems. This enables developers to quickly implement a capacitive touch sensor unit in equipment that require a detection function.

Material Detection Solution includes design support materials:

  • Electrode interface circuit diagrams
  • Sample program
  • Guidelines for the newly implemented detection functions

Moving forward, Renesas will continue to pursue the development of embedded solutions that deliver increased endpoint intelligence for the Operational Technology (OT) field.


The Material Detection Solution is available now for free download at

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