I hadn't seen this before, but I've been looking into building an Arduino controlled box joint jig, and I think the principle of the rip-it is sound. I didn't see where the $800 that Doug mentioned was, but it has some bells and whistles on it ( like built in LCD screen) that could be eliminated by going the Arduino route to save quite a bit of money. Of course, you'd have to learn to write GRBL code to program your control unit. But there may be some free code already written on sites like GitHub.com . I think it's one of those things that you can do without, but it would be interesting to try to build your own.