24V 8-Channel 10A PC USB Control Switch Relay Module Free Drive Programmable Computer Control Computer USB Control Switch Driver PC Intelligent Co...

Not much instruction but you can figure it out by downloading the software via the link in their description. Works right out of the box, I bought a single channel and a four channel one, they both work great. Pros: - Easy setup - No need additional power supply for the single channel, you will need one with 4 channel or more as it needs more current to drive the relay. Cons: - Cannot use extra same units on the same system because the ID is the same. So for example, if you want to have two channels you cannot use two single channel ones because they have the same ID. You will have to buy a four channel one. - Does not come with the USB cable (its forgiven for the price). Notes: - If you plug in the system that does not recognize the USB HID device, in my case Embedded Windows XP, then you will need to install the driver for FTDI chip. The driver can be found here https://ftdichip.com/drivers/d2xx-drivers/. Note this one does not use the FTDI chip physically, however, they do mimic that of, probably running V-USB in the firmware.

The 32 bit dll file makes this incompatible with control on Windows machines using your 64 bit Python/Java/Labview code. Documentation on how to get around this is lacking. Honestly an Arduino is a better option for controlling any relays you need as it can facilitate additional logic and UDP capability. The documentation on an Arduino is also substantially better.

It works very easily with Ubunto. Just apt get usbrelay and it works. For Redhat Linux usbrelay is not available and doing a local build did not work either. I found crelay, that one I was able to build that one locally. Once I got that in place it is working as expected.

This device is based on some open-source Arduino designs with V-USB. That was a clever and cheap concept, but the USB signals are not the best. The device works well enough most of the time, but it wouldn't work in the one Hub I tried.

It arrived well packaged and on time. I plug it in and its recognized by the computer and easy enough to communicate with. The problem with mine is one of the relays works great, the other one only half way works. When the relay is activated, the connection between NC and COM opens up like it should, but the connection between COM and NO never closes. The Normally open path for my left relay cannot be closed. My right relay works as expected.