Xihua Lin
Xihua Lin
Senior staff engineer

Due to the long-standingCOVID-19 pandemic, the demand for touchless control has been increasing since last year. As a counter measurement for the spread of infection, people are hesitating to touch the buttons of public machine, such as elevator, vending machine, etc. In addition, demand for touchless control for kitchen appliances are 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 new ‘Touchless Button Demo Solution’ by using Renesas microcontrollers (MCUs) with a built-in capacitive touch sensor unit (CTSU). The solution use electrodes to detect the approach of fingers or hands without any physical contact via self-capacitance method. LED and buzzer sound will be turned on as user feedback when the proximity of the finger is detected. The detection distance can reach as far as 15mm with a small sensing size of 3*3cm electrode. This solution also complies with IEC61000 4-3 Level 3.

Touchless Button

The Touchless Button Demo Solution is compatible with 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 USB cable. The whole demo is powered from RX130 CPU board via the USB.
  2. Confirm the correct connection of kit and load the sample program into RX130  MCU using e2studio IDE. (The sample software can be downloaded from 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 the performance.

Compared to existing touchless control solution based on sensors, image recognition, etc., Touchless Button Demo Solution can provide a cost-efficient method which can be implemented easily. Comparing with infrared or ultrasonic sensor, the solution is less susceptible to sunlight and other blockages. Comparing with voice or image recognition, BOM cost increase is very insignificant. In addition, other functions like system control, physical touch can also be realized using the same microcontroller.
In summary, Touchless Button Demo Solution is a good choice for non-contact operation in everyday infection control. 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 which users can use for their development of touchless design quickly using Renesas RX130 MCU.

Watch this video to understand this solution clearly.
Feel free to check out this solution with application note and sample code.

Click here for the Capacitive Touch Sensor Solutions.
Click here for the Touchless Button Reference Design
Click here for the RX130 CPU board.


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Videos & Training

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.

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