[jwatte]

I'd like to add an intermittent air burst, that blows for about 0.7 seconds every 5 seconds of cutting. Ideally, without stopping motion. I imagine I'll use an air control solenoid on a separate feeder hose from my compressor (which also feeds the power drawbar.)

With the Tormach USB I/O board, I could set this up with M codes, except I imagine I'd have to program the M codes manually, and I'd have to figure out where in each G code movement would be the appropriate time. Not great!

I guess there are three questions here:

1) How do I map the post processors "air blast" feature to a particular M code?
2) Could I program the I/O board to do the intermittent bursts for me? Or perhaps hook up some 555 timer monstrosity that is in turn triggered by the USB I/O M-code?
3) Or is there some way to hook into the PathPilot / LinuxCNC setup to generate the appropriate pulses? (I wouldn't need the Tormach I/O for this; I could do my own then, based on an Arduino or Teensy or something.)

I poked around in the PathPilot code a bit, and I found the "schnozz" module which controls the smart-cool; it seems to be a convenient way of learning things I'd like to do. (Also, I'm glad to see that SmartCool uses Dynamixel servomotors, which I've used for several robotics projects!)
But how do I best learn how to add modules to PathPilot? How do I get it to load my module? How do the modules communicate? Is there some hacker's guide or something somewhere?

[sharmstr]

PP is a heavily modified version of linuxcnc. You can learn all about it here: LinuxCNC

If it were me, I'd bite the bullet and get Smartcool. I have it and absolutely love it. Being someone who has hacked the crap out of PP, I still think its worth the high price tag.

[jwatte]

I've certainly eyed the smartcool, too :-)
That being said, I'd love to understand more about what vectors there exist for hacking PP.
For example, is there a "user plugins" folder where scripts are loaded, so I don't have to patch the PP after each version update?

[sharmstr]

For example, is there a "user plugins" folder where scripts are loaded, so I don't have to patch the PP after each version update?

I wish. I've asked for it but its fallen upon deaf ears.