Looking for two-input comparator with hysteresis

[Robert Latest]

The isolator also makes a pretty good (open collector, usually)
driver for the logic circuit too.

Not fast enough for reliably clocking a synchronous counter.
Especially since the LED is driven by a slowly changing signal,
too.

So you have the choice: Use an optical insulator where it doesn't
make a helluva lot of sense, or use 1/6 of a hex schmitt
inverters and get 5 free for other potential uses in the same
circuit.

The fact that the hex inverter is a lot cheaper than the OI won't
matter for a hobbyist's one-off.

robert