Express shipping (DHL World Wide Express Service, 38.00 USD per order)


Shipping by ground for EU (26.00 USD per order)


Expedited shipping with DPD (32.00 USD per order)


Economy shipping (Registered Priority Mail)






Ebay Store

USB Four(4) Relay Output Module,Board for Home Automation

This is Four Channel relay board controlled by computer USB port. The usb relay board is with 4 relays RAS-05-15 (JQC-3FC/T73 DC5V). You may control devices 220V / 120V (up to 4) directly with one such relay unit. It is fully powered by the USB port. Suitable for home automation applications, hobby projects, industrial automation. The free software allows to control relays manually, create timers (weekly and calendar) and multivibrators, use date and time for alarms or control from command line.

Relay Type:
Price: €14.67

Estimated Shipping with Posts

starts at €4.99
Send to friend Rate this product Add to wishlist Compare


This is relay board with 4 SPDT Relays controlled from USB port of your computer. The main purpouse of this USB relay module is to help you building projects regarding robotics and home automation (domotic). You may control differenet electrical devices like home lights, DC motors, pneumatic cylinders, lasers and so on. Each such board requires one USB port. The more USB ports you have the more such relay units you may connect and control. We provide several powerful software tools + many software examples.



  • 4 SPDT Relay channels - selectable by user:
    • JQC-3FC/T73 DC5V (7A / 250VAC, 10A / 125VAC, 12A / 120VAC, 10A / 28VDC)
    • RAS-05-15 (10A / 250VAC, 15A / 120VAC, 15A / 24VDC)
  • PCB parameters: FR4 / 1.5mm / two layers / metalized holes / HAL / white stamp / solder mask / еxtra PCB openings for better voltage isolation / doubled high voltage tracks
  • Power supply: from USB port
  • Current consumption: 400 mA
  • Chip: FT245RL. Datasheet - here
  • Power led: Yes
  • Relay leds: Yes
  • Size: 77mm x 56mm x 17mm
  • Supported by DRM software (Windows 32/64 and Linux 32): Yes
  • Supported by Denkovi Command line tool (Windows 32/64 and Linux 32): Yes - New
  • Software examples - here
  • Documentation: here



  • High quality
  • Low cost
  • No extra power supply
  • Software with many functions
  • Control electrical devices according weekday/date/time
  • Create timers or pulses with our software



  • Home automation
  • Robotics
  • Alarms
  • Timers
  • Open doors and windows via PC
  • Aquariums applications


Additional information:

Each such usb relay board is shown as separate virtual com port (VCP) on your PC. The relay module outputs are controlled by FT245RL. It has 8 bit data output register (this device use only 4 of them). When data is sent to the register the outputs are set. If you are software developer - be sure "Synchronous Bit-Bang Mode" is selected! FTDI provides Bit-Bang Mode documentation. See this. The usb relay card can not be controlled directly via COM port - you need to download our DRM Software to control the device. The usb relay unit can not work without PC. Only one such device can be supplyed from single USB port. If you want to supply many such devices you need USB HUB with extra power supply. 


How to connect inductive loads


Denkovi Relay Command Line Tool 

The main goal of this project is to help you to use our USB relay boards easily and without any specific knowledge how do they work. This tool is actually shell for all our USB relay boards and it does not matter which is the relay board, the command is the same. Just type one command and the the tool will set, get relay status or even will take temperature value from the board sensor (if any). It can be integrated in other software and you don't need to know much about how the USB relay board protocol. With this tool it is like a "game" and it takes literaly minutes to create for example PHP script and control the USB relay board from smartphone browser.

Typical applications for this software are:

  • Create desktop icons to turn particular relays
  • Create BAT/BASH files to make more complex logic (like timers for example)
  • The commands can be executed from PHP script
  • Control our USB relay boards from Android / iPhone mobile devices
  • The USB relays can be controlled from each software/platform which can run external executable files or commands in command line promt

Example commands:

LIST COMMAND - lists all devices connected to computer.

java -jar DenkoviRelayCommandLineTool.jar list 


STATUS COMMAND - display relay(s) status(es).

java -jar DenkoviRelayCommandLineTool.jar DAE0006K 4 2 status

java -jar DenkoviRelayCommandLineTool.jar DAE0006K 4 all status


SET COMMAND - set relay(s) state(s).

java -jar DenkoviRelayCommandLineTool.jar DAE0006K 4 2 1

java -jar DenkoviRelayCommandLineTool.jar DAE0006K 4 all 0

java -jar DenkoviRelayCommandLineTool.jar DAE0006K 4 turn 1110


For more information - here

For download - here

Windows: tested on XP, Vista, 7 and 8

Linux: tested on Ubuntu and OpenSuse





Demo video how you can control the USB 4 Channel relay board from command line, browser and tablet the same time because of our command line tool.


DRM Software 

The device is supported by DRM Software. DRM Software is Windows/Linux software for controlling all our relay boards. Supported OS:

Windows: tested on XP, Vista, 7 and 8

Linux: tested on Ubuntu and OpenSuse

Denkovi Relay Manager Software (DRM Software) and USB 4 Relay Board
DRM Software image - control mode for USB Four Channel Relay Board


For more information about DRM Software, documentation and download - here

Download the last version (install package) - DRMsetup.exe

Download the last version (intstall archive) - DRMsetup.rar



More videos  

Control USB Four Channel Relay Board from Android Tablet browser
Demo video with DRM Software and USB Four Channel Relay Module




Here it is shown how you can control 5 of these USB Four Relay Modules with one notebook. It is used USB hub expander with extra power supply.



USB 4 Relay Board controlled by Freedomotic framework

Useful links: 

  • FTDI web page - here
  • FTDI drivers page - here
  • FT245RL page - here
  • Programming guide for FT245RL - here
  • FT245RL Bit Bang Mode - here
  • FTDI official page with source code examples - here
  • DRM Software download - DRMsetup.exe
  • Denkovi Relay Command Line Tool - here


Software examples




Shopping Cart

Cart is empty.


We are happy to remind you that you can get discounts from our web shop. Bellow are given the available discounts based on order subtotal amount:

from $0 to $350, discount is 0%

from $350 to $500, discount is 5%

from $500 to $1000, discount is 7%

over $1000, discount is 10%

For EU Customers

All prices are WITHOUT VAT 20.00%

If you are located in EU and your company has valid VAT number we will reduce the VAT charge AFTER you make the order as our site does not support online VAT number validation. We do it as partial refund. You can use this online tool for VAT validation: