Re: [CAD_CAM_EDM_DRO] CNC band saw, FPM LED display

In a message dated 10/16/2003 12:18:59 AM Central Standard Time,
dk1machine@... writes:
Anyone know of a source for a low-cost display and appropriate
electronics (or a schematic to build same) that will count the input
shaft turns
I needed to count turns on my engine-lathe which I also use for winding
transformers, so I mounted a salvaged loudspeaker "alnico" magnet in a delrin
collar, and put two Hall-effect sensors on a tiny PCB-mount so that the magnet
passed by them both so that they provided a "quadrature" output (one was ON when
the OTHER one changed ON/OFF (or OFF/ON)) (that is, the two Hall-effect IC's
(look kinda like TO-92 transistors) could be BOTH "covered" by the magnet at one
time). This provided "TTL outputs" (actually, "HCmos" output swings!), and
is VERY reliable.


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