A relay is a switch that can be used to control large current devices. It is especially useful in home automation, motoring and robotics applications.
This is a 5V, 2-channel relay module that can handle up to 10A current with 250V AC or 30V DC. A distinct feature of this module is that it can be controlled from a PC via USB port. It present itself as a HID class device, therefore no driver is required.
There is one green power indicator LED on the board. Each relay channel has a red status indicator LED and three output terminals (Normally Open, Normally Closed and Common terminal - marked on the underside). The status LED lights when the Normally Open contacts get closed.
The board is USB-powered, no external power is required to trigger the relay. However, there are 2 solder pads that you can use to connect to external 5V DC.
Software
For Windows environment, a software package with sample codes (C++) and libraries will be provided that can help you to develop your own control software. Command line and GUI control software are included as well that you can use to operate the module.
Take note: It is reported that this module doesn't work on Windows 7/8 64-bit system. Windows 7/8 32-bit is fine though.
For Linux (yes, this includes Raspberry Pi and BeagleBone Black), darrylb123 has written codes that uses a cross-platform HIDAPI library. You can use it as a starting point to control this relay.
Other components required
Only the relay board is included. You'll need a USB Type A to B cable to connect it to a host. You might already have them around but if not, be sure to buy them as well.
Warning: Mains electricity can kill you. Please consult with a licensed electrician if you are working with the mains!
Features:
5V 2-channel relay board with USB control
Has to be connected to a USB host. Doesn't work standalone
SPDT type relay with one normally open terminal, one normally closed terminal and one common terminal
