On Fri, Jun 5, 2020 at 9:58 AM N <nicklas.karlsso...@gmail.com> wrote:
> USB should be able to handle real time but think it is complex which might > be a reason to avoid it and there are no support in Linuxcnc. Andy posted a clear example that shows a simple way to move data from USB to LinuxCNC. https://emergent.unpythonic.net/01198594294 Read the Python code that you find by following the above link. Technically this is easy. Now to think about what a user should see on the hand controller and how he should interact with it. I think e-stop is a desired feature but it will never be as reliable as one that is wired to the machine that does not depend on computer software. USB does have a short maximum cable length but it should work. The example linked above would work for WiFi or BlueTooth too. Once you see how it works the method of communication is unimportant, you are simply setting and reading HAL pins from userspace. > There are however a lot of cheap development boards available which may > make it a very cheap and good choice. There are standard protocol for > keyboard and mouse but do not know about this kind of input you want. > > Switching noise might be a problem if connected to power electronics but > not to hand held device. > > There is Modbus available in Linuxcnc. It might be a little bit slow > nowadays but expect it more than good enough for buttons. Think it is also > simple and no problem to build a device using one of these development > boards available but otherwise a Modbus Remote IO Module might be a good > choice. > > > Emergency stop, any plan for this? > > > > I have actually been wondering about the same/similar thing, on how to > > feed information into hall. > > > > On 6/4/20 2:33 PM, Chris Albertson wrote: > > > I'd like to build a handheld pendant controller. I have some ideas > about > > > how it should work. One thing I want is an LCD screen. This could > evolve > > > into a "smart pendant" that can do things like move along an arc, > rather > > > than just one axis at a time. > > > > > > I think the best physical interface from a handheld device to the > computer > > > is USB. Is there a way to get data from USB to HAL? I could use a > USB > > > virtual serial port but then the question is getting serial port data > to > > > HAL. > > > > > > Maybe the best interface is wireless, so how to get data from a UNIX > socket > > > to HAL? > > > > > > Note that we don't need "hard" real-time to the computer. Latency of > a few > > > tens of milliseconds is acceptable for a human interface so this could > be > > > done in userspace. If so, then maybe all I need is a way to get data > from > > > an arbitrary Linux application to HAL. > > > > > > It just occurred to me that this "arbitrary Linux application" could > be the > > > Apache webserver. Then you run a browser on the tablet. > > > > > > Summary: How to move data from USB or serial or socket to HAL? > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
