Re: Analog Opto Isolator?

Graham,
The zener with a resistor would work but I get no isolation. I would
have to tie the micro ground to the EDM ground which would be seeing
all kinds of RF from arcing. Peter Homann's suggestion of a digispeed
with a zener to protect it should work. I was hoping for something
simpler.

What I wanted to do was to add a sense circuit to Jon's spark EDM. The
Armite micro has an A/D and talks USB RS-232 so it can talk to Mach3
on the mill. Mach3 through a charge pump could raise or lower the Z
axis as commanded by the Armite. I was hoping to keep it simple and
cheap enough so anyone could build add one to their mill with a
minimum of cost and effort with no circuit boards.

I am going to need to cut some rectangular holes in tempered clock
type springs.

Roger

> You could just use a zener diode to limit the voltage to acceptable
> levels.
>
> Graham
>