This is for a CNC quilting machine. Need to send a "pause" command to the machine when the bobbin reaches a certain number of rotations, so that I can change the spool before the machine runs out during the operation. I imagine the use of an arduino board, some type of light reflective sensor, and a way to send a command to the machine kinda like a limit switch, except triggered when a certain number of rotations is reached? and instead of stopping the machine it would pause the machine and give me a "resume" option when ready. Any help would be greatly appreciated.