missed step detector

While attempting to connect up a disk drive to run the stepper motor as
previously suggested by Arnie, I thought supposing you have "large" stepper
to move your machine and the the board and stepper from a disk drive and
have both connected. If you then go for the simplest solution fit a dial and
pointer to to both motors , mark out and number the steps or every 10 if
convenient the the almost no load small stepper should make no errors and
can be compared to the main one any time the machine stops. due to murphys
law the no of steps per turn will be different for each motor so you may
have to mark your dials to reflect this or divide the signal supplyed to the
small stepper You could get clever using lights shining through holes in
disks as a lost step warning device or even to generate the lost step but
then its lost the advantage of easy and very cheap.