A touchless button solution can be widely used in homes (lighting switches, bathroom switches, etc.) and public locations (vending machines, electric door openers, etc.). A touch can be detected without directly touching the button; therefore, the adhesion of bacteria and dirt to the fingers is reduced. The touchless button solution lessens concerns over contaminated surfaces.

Renesas offers a reference design for the touchless button solution. To learn more, see the Touchless Button Reference Design page.

System Benefits​:

  • Entry-level RA 32-bit MCU with a Capacitive Touch Sensor Unit 2 (CTSU2) provides touchless control with high sensitivity and high noise immunity. All Renesas MCUs that contain a CTSU are also compatible.
  • Ultra-low Iq buck-boost can fully extract the power of a battery as low as 1.8V.
  • Output voltage can be adjusted by the I2C bus.




  • Elevators, vending machines, ticket selling machines
  • Toilet flushing, water faucets
  • Automatic door buttons
  • Kitchen appliances: Refrigerators, microwave ovens, range hoods, etc.

Winning Combinations Interactive Diagram

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Template 1 Connector Arrow.218 Optional Non-Renesas Component Option Option Connector Arrow.183 Diode Sheet.65 Sheet.66 Sheet.67 Connector Arrow.37 Touch Key Sheet.39 Sheet.40 Sheet.41 Sheet.42 Sheet.43 Sheet.44 Sheet.45 Sheet.46 Sheet.47 Touch Key.48 Touch Key Touch Key CN318 CN318 CN318 AC Line AC Line AC Line Plug Sheet.169 Sheet.170 Sheet.171 Sheet.172 AC Power Source.172 Sheet.174 Alternating Current LED Driver LED Driver LED Driver Connector Arrow.180 Sheet.182 LED Segment Display Sheet.124 Sheet.125 Sheet.126 Sheet.127 Sheet.128 Sheet.129 Sheet.130 Sheet.131 Sheet.132 Sheet.133 Sheet.134 Sheet.135 Sheet.136 Sheet.137 Sheet.138 Sheet.139 Sheet.140 Sheet.141 Sheet.142 Sheet.143 Sheet.144 Sheet.145 Sheet.146 Sheet.147 Sheet.148 Sheet.149 Sheet.150 Sheet.151 Sheet.152 Sheet.153 ON ON Sheet.154 OFF OFF Sheet.155 Sheet.156 Sheet.157 Sheet.158 Sheet.159 Sheet.160 Sheet.161 Sheet.162 LED LED LED Connector Arrow 3.3V 3.3V 3.3V RS-485/422 RS-485/422 RS-485/422 Bi-directional Bi-directional.189 RS-485 RS-485 RS-485 Buck-Boost Buck-Boost Buck-Boost Buck-Boost VIN VIN VIN VOUT VOUT VOUT I2C.197 I2C I2C Connector Arrow.199 Isolated AC/DC Isolated AC/DC Isolated AC/DC Connector Arrow.203 Connector Arrow.204 Battery 2-Cell Sheet.206 Sheet.207 Sheet.208 Sheet.209 Line 1pt.1552 Line 1pt.1608 Ground (earth) Sheet.213 Sheet.214 Sheet.215 Sheet.216 Bi-directional.219 Connector 1.160 3.3V.221 3.3V 3.3V Bi-directional.223 MCU MCU MCU MCU UART UART UART CTSU CTSU CTSU PWM GPIO GPIO I2C I2C I2C ADC 2 12-bit ADC 12-bit ADC
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