This Automatic Liquid Dispenser reference design is for hands-free dispensing of liquids such as soap, hand sanitizer, shampoos, or hand lotions. Automatic liquid dispensers are popular in public places and private institutions, as touch-free designs eliminate bacterial transmission. The dispenser only distributes a set amount of liquid per motion activation to minimize waste. When a hand is detected near the nozzle, the MCU triggers the pump motor and the dispenser emits liquid. The liquid is automatically dispensed without the hand touching any part of the nozzle, resulting in a more hygienic environment. When a hand comes close to the nozzle, it blocks the transfer of optics between the infrared LED and photo transistor. The MCU detects the change in the photo transistor status, and then activates the motor.

This solution features the RL78/G11 low pin and internally configurable analog MCU which operates the system clock with a medium-speed on-chip oscillator, achieving low-power consumption and a fast wake-up of 4μs. It also features the ISL9001A high performance low dropout linear regulator used for power management can source a current of up to 300mA. This regulator helps extend battery life as it supports a wide input voltage range (2. 3V to 6. 5V) while featuring extremely low quiescent current.

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Disclaimer: THIS MATERIAL IS PROVIDED “AS-IS” FOR EVALUATION PURPOSES ONLY. RENESAS ELECTRONICS CORPORATION AND ITS SUBSIDIARIES (collectively, “Renesas”) DISCLAIM ALL WARRANTIES, INCLUDING WITHOUT LIMITATION, FITNESS FOR A PARTICULAR PURPOSE AND MERCHANTABILITY. Renesas provides evaluation platforms and design proposals to help our customers to develop products. However, factors beyond Renesas' control, including without limitation, component variations, temperature changes and PCB layout, could significantly affect the product performance. It is the user’s responsibility to verify the actual circuit performance.


  • Demo board includes the RL78/G11 MCU
  • Dispenser distributes a set amount of liquid per motion activation to minimize waste
  • If hands are placed under the nozzle, an LED and buzzer are turned on to indicate liquid dispensing
  • Even if hands remain under the nozzle, liquid dispensing has a maximum duration of 2 seconds
  • When battery voltage is lower than 4.8V, an LED blinks to indicate this low power condition when hands are placed under the nozzle.
  • Amount of liquid per motion activation: 0.5ml/0.8ml selectable



Type Title Date
Brochure PDF 12.02 MB 日本語
Other PDF 351 KB 日本語 , 简体中文
Other PDF 482 KB
Datasheet PDF 662 KB
4 items

Design & Development

Sample Code

Automatic Liquid Dispenser

Renesas demonstrates the Automatic Liquid Dispenser quick solution featuring the RL78/G11 microcontroller. This solution uses a built-in infrared sensor and pump mechanism to detect hands and dispense a fixed amount of liquid, such as dish soap, hand sanitizer, shampoo or hand lotion.