Re: ParPort output low - hi-Z or ground?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "caudlet" <info@t...> wrote:

I'm taking the LED power from a floppy connector so that the
controller board and opto's are on completely different power
supplies.

> I am an EE with enough experience and spare parts to build any kind
> of IO interface I want. I bought a Campbell board.

I hear ya! 8) I was (am) really tempted to buy a Xylotex board.
parts/pcb costs alone is pretty close a complete board solution.
Thing is, having a CNC controller is only 1/3 of the reason for
building it myself. You see, my actual hobby is learning.
Electronics, metalwork, woodwork, plastics etc are simply the
vehicles that bring me more knowledge. I would actually rather build
something myself even if the end cost is higher than purchasing
complete units. In terms of $/hour, I think of it more in terms of
tuition than in wages. Some things are beyond me or simply WAAAY to
expensive to build compared to purchasing (PIR sensors for example).

So I was correct in assumning that its safe to sink LED currents with
parallel port pins then I assume? The port inputs I have wired
opposite the outputs. The LED power is supplied from the controller
and the port inputs are active low.

I'll send a PDF to the files section after I remove the redundant
transistor arrays and simplify (a lot!).