Amazon link below. You can also get it on Bangood and on eBay. There’s another version of this that has an RS-485 interface so you can connect it to a computer. (I don’t think Amazon sells it.). For the box, I used an electrical 4x4 box with a standard electrical outlet cover plate. I just cut a hole in it. It’s very easy to wire. If you decide to build one let me know and I’ll give you some suggestions.