Xihua Lin
Xihua Lin
Senior Staff Engineer
Published: July 16, 2021

Due to the long-standing COVID-19 pandemic, the demand for touchless control has been increasing since last year. As a counter measurement for the spread of infection, people are hesitant to touch the buttons of public machines, such as elevators, vending machines, etc. In addition, demand for touchless control for kitchen appliances is also increasing as users often find it difficult to touch the equipment with their hands if they are dirty or wet.

To meet these needs for touchless control, Renesas offers a "Touchless Button Demo Solution" using Renesas microcontrollers (MCUs) with a built-in capacitive touch sensor unit (CTSU). The solution uses electrodes to detect the approach of fingers or hands without any physical contact via the self-capacitance method. An LED and buzzer sound will be turned on for user feedback when the proximity of a finger is detected. The detection distance can reach as far as 15mm with a small sensing size of a 3cm x 3cm electrode. This solution also complies with IEC 61000 4-3 Level 3.

Touchless Button

The Touchless Button Demo Solution is compatible with the RX130 CPU board. With the Capacitive Touch Development Tool "QE for Capacitive Touch", it is easy to set up and implement this solution.

  1. Insert the RX130 CPU board into the demo solution and connect it to the PC via a USB cable. The whole demo is powered from the RX130 CPU board via USB.
  2. Confirm the correct connection of the kit and load the sample program into the RX130 MCU using the e2 studio IDE. (The sample software can be downloaded from the Renesas website.)
  3. Build and Run the sample program and evaluate the performance of the demo. Open "QE for Capacitive Touch" to check the measurement result and adjust relevant parameters to improve performance.

Compared to existing touchless control solutions based on sensors, image recognition, etc., the Touchless Button Demo Solution can provide a cost-efficient method that can be implemented easily. Compared with an infrared or ultrasonic sensor, the solution is less susceptible to sunlight and other blockages. And when compared with voice or image recognition, the BOM cost increase is very insignificant. In addition, other functions like system control and physical touch can also be realized using the same microcontroller.

In summary, the Touchless Button Demo Solution is a good choice for non-contact operation in everyday infection control. The capacitive sensing function provided by Renesas microcontrollers makes it possible to have touchless button operation simply and profitably. We have reference boards, sample software, etc. available that users can use to develop touchless designs quickly using the Renesas RX130 MCU.

Additional Information

Watch the "Touchless Button Demo" video to understand this solution clearly.
Feel free to check out this solution with the "Touchless Button Demo Solution Sample Software" application note and sample code.
Learn more about our Capacitive Touch Sensor Solutions.
Learn more about the Touchless Button Reference Design.
Learn more about the RX130 CPU board.

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Touchless Button Demo

The Renesas Capacitive Touch MCU touchless user interface demo is able to detect the approach of fingers or hands without any physical contact by using high sensitivity, high noise immunity capacitive sensing technology.