Quote Originally Posted by irving2008 View Post
look on fleabay for "slotted opto", returns half a dozen options... just the device.. will need mounting on a small circuit board with a couple of resistors, and you'll have to rig up some sort of vane on the spindle to interrupt once per rev...

Alternatively, and more easily, if you are set on the ebay display, use a 74HC390 divider chip to give a 'divide by 50' with only 1 chip and 10 solder joints!
Ok that sounds good but this is uncharted ground for me, the 74hc390 seems like the way to go and i will get a new slotted sensor just to be on the safe side as i dont know if the existing one is ok, you make the circuit sound so simple ill just trust your judgement over mine:confused:



Rick