Start / Continue button

[Hong Mai Ha Osterstrom]

   I am using a Beaglebone / CRAMPS 2.2 cape fitted with Protoneer ‘Pololu Socket To External Driver conversion boards’ to provide signals to the large drivers and steppers on my (bigger-than-a-Bridgeport) retro-fitted Induma mill. The X and Y axis's are working as they should so I can use the mill in 2 axis mode to build the mounting hardware for a CNC quill feed to give me a Z axis.
   Every thing is going fine but I really, really miss having a  working ‘Start / Continue’ button right next to the big red E-Stop button on the head of the mill. I have a fun little 3D printer so I quite understand why the CRAMPS cape doesn’t need to implement such a button but I am dealing with several hundred pounds of Iron moving at 4+ inches a second. Mousing about on a simulation of what I hope is happening is not the same as facing what is really happening with my thumb hovering over the E-Stop button.

   I ran LinuxCNC on a friends mill in the late 1990s and it had a real ‘Start / Continue’ button. Did that capability get carried over into Machinekit and if so, where does it emerge on the Beaglebone? I already have a pair of 2 X 23 stacking headers between the Beaglebone and the CRAMPS cape to improve cooling so it would be no big deal to add a breakout board. Any information would be welcome.

  

By the way, I am using my wife's account. My name is Gordon Osterstrom

[Charles Steinkuehler]

If you're not using all the limit switch connectors, the easiest thing
would be to just connect one of those to your button. You would turn it
into a start/continue button via HAL wiring.

Also, I'm not familiar with the Protoneer boards you're using, got a
link? If they are just straight wiring, like these:

https://www.ebay.com/itm/Pololu-connector-socket-converter-jumper-board-for-External-Driver/202696098969

...be very careful. There is no buffering on the CRAMPS board for the
step/dir signals, so these will be low drive 3.3V logic directly
connected to the BeagleBone. It is *VERY* easy to fry the BBB if you
ever go above 3.3V or below Gnd on these I/O signals.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Hong Mai Ha Osterstrom]

Thank you for your prompt reply. There are plenty of rapid ways to manually home the quill feed on a mill so the ‘Z’ limit pins are certainly available. I guess I have put off learning HAL programming for about as long as I can. At least I will have plenty of time to work on it.

Protoneer is a New Zealand company that mostly serves the needs of the GRBL community down that way. Their eBay store is shut down at the moment because New Zealand is doing a hard lock-down. I came across them when I was looking for alternatives to LinuxCNC running on near voting age Intel PCs to run my mill. Fortunately, I also came across Machinekit on the Beaglebone and judged it to be a more capable choice.

The Protoneer driver conversion boards are very similar to the boards you mentioned but I already had a bunch of them on hand when a job came along that I really didn’t want to turn down. I am aware if the voltage sensitivity problem and was starting to design an optical isolation board but I couldn’t afford to wait so I used them. So far I have been lucky but even if I fry 10 Beagles, I still make a profit and keep a probable future customer.