On Sun, 2017-01-29 at 13:10 -0500, Gene Heskett wrote: > On Sunday 29 January 2017 12:16:52 Jonathan Wilson wrote: > > > On Sun, 2017-01-29 at 08:47 -0500, Gene Heskett wrote: > > > Greetings everybody; > > > > > > I am in the process of bringing a nearly 70 yo Sheldon lathe back to > > > life, useing an raspberry-pi 3b for the machine controller. > > > > > > However, I have now had 5 different keyboards plugged into it, some > > > wired, some wireless, and none of them can give me a dependable > > > response to a key, and the error seems much worse for the key-up > > > event. When driving the machine by hand as we often do for one-offs, > > > missing a keyup event can be disastrous for the part being made > > > because it keeps on cutting until you've given that, or another key, > > > a quick tap to stop the unwanted motion. > > > > I'm wondering if the problem is noise on the power, or RFI noise being > > picked up/interfering with the usb cable and/or PI in general. I'm > > guessing that the lathe is probably kicking out a shed load of RF > > noise into the air or on to the power line and the pi is not overly > > hardened for such a harsh environment. > > Understatement of the month... :)
:-) Its a good old British tradition to always understate ;-) > This application, linuxcnc, is largely written in python, but I'm not fam > enough with python to go mucking about in its internals. And the fact > that 3 other installations of the same code on x86 boxes do not have > this problem tends to point a pretty stiff finger at the pi. Yeah, the PI is made down to a price point (Although I'm fairly sure it meets some CE requirements: https://www.element14.com/community/docs/DOC-43262/l/updated-29-march-frequently-asked-questions-about-raspberry-pi but it may be that any standards regarding "input noise", as opposed to it generating RFI, are possibly not met, likewise input shielding, de-coupling, etc.) ... X86 boards not only have to meet Intel standards but also a host of International and US standards and I'm guessing that some of the standards, either international or Intel, exceed the minimum legal/ISO/CE requirements (for being able to sell into markets) when taken as a whole. > > > > There is something funkity in the usb keyboard handling that can get > > > much worse with a reboot, or get almost perfect with a reboot. > > > > > > Its all uptodate a/o yesterday. The psu is a 4 amp box, making 5.07 > > > volts solidly. Verified with a 100 Mhz scope. > > > > > > What can I do to fix this? > > > > > > Cheers, Gene Heskett > > Thank you. There might be the seeds of a fix in this. You're welcome. > > Cheers, Gene Heskett
