Capacitive Touch HMIs: Advanced Solutions for Intuitive Interfaces

Capacitive Touch Technology for a Connected World

Capacitive touch keys are revolutionizing human-machine interfaces (HMIs) by replacing the fixed functions of mechanical switches. These keys offer more intuitive interfaces that incorporate complex and sophisticated operations, making them suitable for a variety of applications. The rapid expansion of capacitive touch keys is driven by their ability to enhance user experience through improved navigation and functionality.

Achieving such intuitive usability isn’t without its challenges. Developers need to tackle obstacles like improving sensitivity, managing noise interference, and ensuring reliable performance—even in real-world conditions, like when hands are wet.

High Sensitivity

Our capacitive touch IP provides enhanced operability under a variety of conditions. Whether it’s sensing through thick acrylic or wood panels in household appliances, our solutions deliver exceptional operability where it matters most.

Noise Tolerance

We've built noise immunity into the core of our solutions. By implementing multi-frequency measurement functions, we ensure robust performance against conducted and radiated RF noise, so your devices operate flawlessly in noisy environments.

Easy Development

With our QE for Capacitive Touch toolkit, development is simple. Running in the e² studio IDE, it makes configuring initial sensor settings and fine-tuning touch sensitivity quick and efficient. This tool can connect your product’s board and enable you to tune sensor settings.

Low Power Consumption

Our capacitive touch products and solutions feature a multiple electrode connection, as well as an automatic judgment function to achieve low-power consumption standby operation.

Capacitive Touch Sensor Unit (CTSU) Technology

Our capacitive touch sensor technology has evolved significantly over time. The first generation relied on third-party IP (SCU/TSCU) and was used in the R8C family. From the second generation, we introduced our own Capacitive Touch Sensor Unit technology through the RX family, later expanding to the Renesas Synergy™ and RA families. Now in its third generation, CTSU2 is advancing further and is incorporated into various products within the RA, RL78, and RX families.

CTSU Features

Reliable Operation in Any Environment

Utilize the mutual capacitance method to ensure seamless operation—even in wet conditions or when touched with wet hands. No unintended malfunctions caused by water.

Industrial-Grade Noise Immunity

Equipped with random pulse frequency measurement, the CTSU meets IEC61000 4-3 Level 3 standards, making it suitable for industrial setups demanding reliable performance in noisy environments.

CTSU2 Features

Simplified Development with Superior Waterproofing

This self-capacitance method simplifies waterproof design, offering better development ease compared to mutual capacitance solutions. Perfect for applications where water resistance is critical.

Medical-Grade Noise Immunity

Featuring multi-frequency measurement, the CTSU2 meets IEC61000 4-3 Level 4 standards, making it ideal for medical applications that demand robust protection from electromagnetic interference.

Energy-Efficient Touch Applications

Touch judgment hardware reduces touch operating current consumption through automatic touch detection.
Multiple Electrode Connection (MEC) lowers touch standby power usage, extending device battery life.

Optimized for Multi-Button and High-Response Applications

Mutual Simultaneous Scan (CFC) speeds up touch measurement through parallel processing, ensuring high responsiveness and enabling support for multiple buttons or applications requiring quick feedback.

MCUs with Touch Function

Discover microcontrollers equipped with capacitive touch functionality. Use the pre-filtered parametric tables to find a product for your touch-enabled designs.

RL78 Low-Power 8 & 16-Bit MCUs

RX 32-Bit Performance/Efficiency MCUs

RA Arm Cortex-M MCUs

HMI Capacitive Touch Applications

Design Resources

Our next-generation capacitive touch solutions and development tools are here to simplify your process and help you design high-performance systems with ease.

Integrated Development Environment (IDE)

e² studio and CS+ are powerful IDEs for Renesas MCU development. e² studio, built on Eclipse, spans from sample code to debugging, while CS+ offers a user-friendly, secure environment with hardware tool support and self-test software.

e² studio

CS+

QE for Capacitive Touch

Streamline sensitivity adjustments for capacitive touch buttons, speeding up development with support for RX Family 32-bit MCUs.

QE for Capacitive Touch

Smart Configurator

Automatically generate initial setup programs for our MCUs, streamlining tasks like configuring peripheral pins, importing middleware, and setting up drivers. Enhance your development process with the latest version for faster, more efficient software configuration.

Smart Configurator

Reference Designs & Demonstration Kits

We offer application-specific reference designs, including waterproof solutions, metal surface touch, 3D gesture control, and touchless buttons. Additionally, we provide capacitive touch reference designs for liquid dispensers and liquid level indicators.

Capacitive Touch Reference Designs & Kits

Evaluation Boards

Discover our capacitive touch evaluation boards, designed to streamline development and elevate your designs. Offering advanced touch sensing, intuitive interfaces, and reliable performance.

Capacitive Touch Boards & Kits

HMI capacitive sensor microcontrollers application note cover.

Capacitive Touch Sensor Unit (CTSU) Introduction Guide

The application note is a beginner's guide to capacitive touch sensors, covering detection basics, MCU options, hardware, software, development tools, and evaluation kits.

Download App Note

Partner Solutions

Accelerate the development of capacitive touch HMI solutions through Renesas' ecosystem of hardware, software, and service partners. From touch controllers and display integration to GUI development and system implementation, discover trusted partner solutions that help reduce design complexity and speed time to market.

Renesas Partner Program

Documentation

Videos & Training

Gain an understanding of the basic knowledge to start capacitive touch development. This video introduces essential knowlege for capacitive touch development. It also provides tips for selecting an appropriate MCU for user applications as well as introducing software development tools for shortening time to market.

Discover how Renesas’ 2nd generation Capacitive Touch Sensor Solution replaces mechanical keys with intuitive touch control. This innovative technology offers precise sensitivity, high noise resistance, and reliable performance in challenging environments, including water, dirt, and temperature variations.

Learn about the Capacitive Touch Evaluation System for RA0L1 (RSSK‑RA0L1), its key features, and how it supports ultra‑low‑power capacitive‑touch development. We will walk through the quick‑start guide document, unbox the hardware, and show how to set up the development environment and generate a project. A hands‑on demo highlights the RA0L1 MCU’s capacitive‑touch performance and demonstrates how the board helps developers begin evaluating the device quickly.

The capacitive touch sensing unit "CTSU2" has enhanced noise immunity functions and supports "active shields." It is also effective in improving the water resistance of self-capacitance touch buttons. In this demo, a GND shield and an active shield have been placed to compare the water resistance of each shielding method.

This video introduces a smart wake-up solution that can reduce standby current consumption by more than 90% compared to conventional products. The hardware uses the RX140 capacitive touch evaluation system and touchless button demo.

Related resources:

Wood, stone, cloth, and paper may be used as cover panels of capacitive touch sensors.

This capacitive touch solution makes it possible to revolutionize design in a restriction-free (material-free and design-free) environment. In recent years, home electronics and other products have been adopting capacitive touch interfaces to improve design and durability. The demand for better demand is becoming especially strong. These solutions enable wood, stone, cloth, paper, and other materials that were previously not used for operating panels of electronic devices, to be used as cover panels for capacitive touch sensors instead of traditional resin materials such as glass or acrylic.