Re: Re: Homing switches

From: stratton@...

>Probably the most common homing switch I've seen is one of the little
>photinterrupter modules - a black plastic case with a slot in the
>middle and two leads coming out of each side - one set is for the
>infrared LED and the other a phototransistor. You connect a little
>tab to the moving slide that blocks the gap. They seem to be pretty
>good and repeatable, provided that you always approach them in the
>same direction and while traveling slowly. For more accuracy, you
>could use the optical module anded with a particulary quadrature phase
>of your encoder that you figure out is located just after the optical
>switch trips...

<s>

If you are running open loop, you can use the photointerrupter and a home
switch. Setup the home switch so that it closes near where you want the
home position and set the photo switch so that a tab or a ring with a
single hole interrupts the photo switch. Wire the switches in series.

Ray