DIY 3020 CNC I/O Board

[ukracer]

How did you get on with this project??

[Pointy]

How did you get on with this project??

It changed quite a bit from that first design, but it works great. You can read about it on my blog. (It's under part 2, I think)

Regards,

Les

[danilo]

For pull up resistor calculations you must consider the current passing through the line. Most diodes require 20mA maximum, so around 15mA will be safe to work with. Based on the diagram, for a 5V supply the pull up resistor (22K) is quite high; remember that there will also be a voltage drop in the opto-isolator.

pcb quote