uhidctl

uhidctl is utility to control USB HID power relays.

Supported USB relays

This utility is designed to work for USB HID power relays which can be found on eBay or Amazon as:

For Smart Home 5V USB Relay Programmable Computer Control

This utility supports such devices with 1, 2, 4, 8 ports (16 port devices will require patching to work). Hardware that was tested to work has following characteristics (N is number of ports):

Property	Value
Manufacturer	`www.dcttech.com`
Product	USBRelay{N}
Vendor ID	0x16C0
Product ID	0x05DF

Compiling

This utility was tested to compile and work on Linux (Ubuntu/Debian, Redhat/Fedora/CentOS) and MacOS. It should be possible to compile it for Windows as well - please report if you succeed in doing that.

First, you need to install library hidapi:

Ubuntu: sudo apt-get install libhidapi-dev
Redhat: sudo yum install hidapi-devel
MacOS: brew install hidapi
Windows: download hidapi

To fetch uhidctl source and compile it:

git clone https://github.com/mvp/uhidctl
cd uhidctl
make

This should generate uhidctl binary.

You can install it in your system using:

sudo make install

Linux USB permissions

On Linux, you should configure udev USB permissions (otherwise you will have to run it as root using sudo uhidctl). Simply add following line to file /etc/udev/rules.d/52-usb.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="16c0", MODE="0666"

For your udev rule changes to take effect, reboot or run:

sudo udevadm trigger --attr-match=subsystem=usb

Usage

To list all compatible relays, run uhidctl without parameters:

uhidctl

To control relay state:

uhidctl -a 1 -p 2

This means operate on default USB relay, turn power off (-a 0, or -a off) on port 2 (-p 2). Supported actions are 0/1/2 (or off/on/cycle). cycle means turn power off, wait some delay (configurable with -d) and turn it back on.