There are several types out there that are simple to use, one being from parallax which is a simple 5V power with serial interface. I used them with IO Control years ago. Another is from Nematron with the optimate series if you want a nice panel mount but with those if you don’t communicate with it within 2 seconds it can start flashing. They’ve been bought out a few times so I’m not sure if they are still available.
Gary