John,
At some point I'm going to make some sort of custom UI board so I can push real buttons and spin knobs for common things like jogging, rates etc. To get those signals to LinuxCNC there are a few obvious options:
1) emulate keystrokes/mouse clicks and send to USB port
2) CANbus
3) hardwire to spare MESA inputs.
4) other methods?
My CANbus experience is superficial.
Response to button presses must be near instantaneous (from UI perspective). If I push the 1mil increment button 10 times as fast as I can, I want it to move 10 mils not 9 sometimes.
If you were to do this what approach makes the most sense for the data interface?
Thanks,
Jeff
For standard interactive I went with two different options:
For LinuxCNC I have something similar to this as the wired option. Not BluTooth.
For the MACH system I find this one very handy and there are those who have it or the big brother working on LinuxCNC too.
Mine is the ShuttleXPress and others have the ShuttlePro
Shuttle Xpress is the compact version of multi-media controller, Multimedia Controller PRO v2. Portable, lightweight and cost effective
contourdesign.com
I can select an axis and move up to full speed or slower or turn the smaller dial one increment at a time. Very handy with MACH3 and I have buttons for spindle ON/OFF.
For Linux the biggest problem I've had with the pendant was the way I store it. Magnets on the back hold it onto the mill. I just reach over and press it and it stays. But... one time I was sloppy and I dropped it. On the way out of my hand my fingers spun the knob. The selection switch was still set on an axis and sure enough it ran the table into a tool bit I think. Don't remember what I broke or how expensive it was. Now before I set it down I switch off the axis selection. Much safer.
Overall what I like about the ShuttleXpress is it sits flat and very easy to move the axis. No need to rotate a switch to select the axis. Just tap X through A and turn the wheel.
Years ago for MACH I bought a MODIO board from Australia. I never made it that far but a friend connected up a keypad and LCD display to it and used it as a pendant. MACH and LinuxCNC both support MODBUS. Easier than running a bundle of wires from the MESA if it's a movable pendant.
I'll dig out my CAN bus interface and post that in a separate reply.