In today’s market, equipping on-off control switches for home appliances is increasingly popular. In terms of aesthetics, conventional switches are larger in size, take up a lot of space and often people forget to turn off electrical equipment in the family, thus causing expensive electricity costs in the family.  

To solve these problems and help make the home smarter, EPI would like to introduce to customers a reasonable price wifi/ble touch switch solution that turns devices on and off with just one touch. and remote control using components from brands that EPI is officially distributing such as: Espressif, Hongfa, HTC,… 

Wifi/BLE touch switch is a switch that applies touch technology to help users turn on and off household electrical appliances such as light bulbs, curtains, water heaters,… with just one touch or Controlled by Smartphone or tablet,… via wifi or BLE.    

The solution uses Espressif’s ESP32 wireless communication module to connect to smartphone devices via wifi and can be used even without internet to remotely control the device on/off.   

Besides, to turn on/off the device correctly, EPI used two relay products HF32FV-G and HF32FV-16 from Hongfa to help the device operate stably and effectively. 


Technical Specifications:

  • Initial voltage range: 150 – 265VAC 50/60hz  
  • Supports turning devices on and off via wifi/ble  
  • High capacity up to 2500W  
  • Anti-shock isolated power source  
  • Response time < 0.25  
  • No-load power consumption: <0.5 W  


  • Safe, anti-electric leakage  
  • Control anytime, anywhere  
  • Anti-shock isolated power supply  
  • Luxurious and sophisticated design  
  • High capacity up to 2500W  
  • Design and sample support from the company 

Key components utilized in the circuit:

1. Espressif – Wifi/BLE Module ESP32-WROOM-32E-N4   


  •  Supports Wifi + Bluetooth 2.4Ghz  
  • Number of GPIOs: 26  
  • Support PCB antenna  
  • Memory: 4MB Flash  
  • Operating voltage: 3.0 ~ 3.6V  
  • Peripheral support: UART, SPI, I2C, PWM, GPIO, SD Card,… 

2. Hongfa – Relay HF32FV-G   


  • Switching capacity: 10A  
  • Dielectric strength: 4KV (between coil and contact)  
  • Coil Voltage: 3 ~ 48VDC  
  • Dimensions: 18.4×15.5×10.2 mm  
  • Number of legs: 4  
  • Coil Power: 450mW  

Learn more: Relay HF32FV-G   

3. Hongfa – Relay HF32FV-16 


  • Switching capacity: 16A  
  • Dielectric strength: 4KV (between coil and contact)  
  • Coil Power: 800mW  
  • Coil Voltage: 3 ~ 48VDC  
  • Number of legs: 4  
  • Dimensions: 18.4×15.5×10.2 mm 

Learn more: Relay HF32FV-16 

4. Other components 

  • Self-healing fuse – LB080F – Wayon  
  • AC and DC capacitors of STE  
  • LDO DC/DC Converter LM1117GS-3.3 – HTC  
  • MB6F storage bridge – Hottech  
  • Relay Driver ULN2003D – HTC 

Contact EPI Vietnam Technologies – Authorized distributor for professional consultation and complimentary support on samples and source code. 

Block diagram

Contact EPI Vietnam Technologies Design solution

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