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... :) This is also a problem, and I currently have a gigahertz sample scope watching the spi bus, which occasionally makes a mistake, particularly when the spindle vfd drive is turned on. I have a bag of ferrite clampons, and I have yet to put any on the usb cable all this comes into the pi on. This spi bus runs at 32 megabits! And the driver generated noise has components whose rise time on the scope measures at the scopes own rise time when I have a Hitachi V-1065 hooked up (100 MHz dual trace, computerized) or a gigahertz sampler I bought two years ago for my 80th birthday, the peak of the ringing is in the 100 MHz range. > > Another possibility is that they keyboard/pi is working ok, but the > pi>lathe is where the problem is. The only way to tell would be to > some how have the application give a visual indication of the keys > pressed state so you would know if the pi had even seen the key > released event. 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. > > 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. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
