USB controlled relay board with 2 channels is used the HID technology.

https://github.com/sonnyyu/UsbRelay

Specification:

Relay type: 5V relay Contack type: NC / COM / NO (250VAC/125VAC/30VDC, 10A)

Input voltage: DC 5V (USB)

How to Cross Compile for Arduino Yun/Openwrt

A tool to control a USBRelay2 board. These boards are based on the V-USB stack from http://www.obdev.at.

Notes:

If you get a message usb.h file missing, you have to install this library:

sudo apt-get install libusb-dev

If you get following message:

./usbrelay get

Warning: cannot query manufacturer for device: error sending control message: Operation not permitted error finding USBRelay2: Communication error with device

Then you had to add sudo in front of the command:

sudo ./usbrelay get
1: ON
2: ON
./usbrelay -h
help: ./usbrelay on|off [1|2|3|4] [-n |all] [-name ] [-h]
-h|--helpprint this help
on|off [1|2|3|4]switch specified relay output on/off
getget relay status
-n |alluse specified relay (if there are more than one relay)
-name use relay with name, default is "USBRelay2"