3D Printer Shutdown Timer, Auto Off Switch

I wanted the ability of a simple addon module that could shut the printer off after its done doing a print BUT i also wanted it to wait for a while to allow the printer to cool down with the fans running before it gets shut off so i came up with this. Most of the time when i do a long multi-hour print i will start it before going to bed and let it crank away through the night, but the problem is i might not be up before its done doing a 6 hour print and i don't want it sitting idle for a couple