Saturday, December 20, 2014

Cool Tool Sandy Box CNC Control

Alexander Rössler and the folks at The Cool Tool have released the Sandy Box CNC controller just in time for the holidays.  If you are unfamiliar with The Cool Tool, they make small CNC machines for research, prototyping, hobby, and education.  While the Sandy Box is primarily intended to control their UNIMAT line of CNC machines, it's possible to use with most any CNC system currently driven by a PC parallel port.

Inside the box is a BeagleBone with a custom cape already setup to run Machinekit.  It should make a great controller for folks looking to upgrade or replace a dated DOS or Windows machine.  If you're interested in using the Sandy Box on your machine, or have any questions, head over to the Machinekit Google group where Alexander and others can answer your questions.

Tuesday, December 9, 2014

BeagleBone Encoder Support

Russell Gower has written a HAL driver for the hardware eQEP encoder inputs on the Beaglebone.  This makes it possible to do rigid tapping with an encoder on your spindle, and paves the way for eventually running high-speed servo systems on the 'Bone (which will likely also need support for hardware PWM, since the existing PRU based PWM isn't really fast enough for motor control).

The new code is merged and built, so you should be able to use apt (or your favorite package manager) to update if you've installed Machinekit from packages.  If not, you should consider doing so (instructions), since it makes it much easier to do updates.

Sunday, November 23, 2014

Jog-while-paused

Recently jog-while-paused popped up again on the LinuxCNC mailing list (this happens a lot, check the archives), so it seems like a good time to point out that not only does Machinekit contain jog-while-paused functionality, this feature was added to LinuxCNC by Michael Haberler before there was a Machinekit project at all.  If you're unfamiliar with the jog-while-paused feature, it allows you to pause a running gcode program, move the machine (perhaps to take a measurement, inspect the cut, or perhaps replace a tool) then resume program operation.

Since so many folks seem to want the feature, but almost no one is using it, what is needed to get jog-while-paused working?  First, you need to have the jog-while-paused code in your build.  With Machinekit, the feature is in all current packages, but with LinuxCNC you'll need to dig around for the proper branches (check the dev-list archives around the date of the video above, Oct. 2013).  This adds new offset pins to motion that provides for the jog-while-paused functionality.

The next piece is some HAL logic to drive the new pins.  There's a simulation example provided with Machinekit (the sim.axis.jog-while-paused9 configuration) which includes some custom UI and HAL code to get jog-while-paused working.

So...what's really missing is just some real-machine example configurations and perhaps a bit of a HOWTO with instructions on getting everything working.  If you've been itching for this feature, why not try out the simulation config.  If you like how it works, merge the jog-while-paused changes into your machine setup.  Remember to take notes and share your results.  Once a few brave souls blaze the trail, I'm sure lots more will follow, and this is a great way non-programmers can help out with the project.

Monday, November 17, 2014

New QtQuickVcp Interfaces

Great news!  Alexander Rössler has released the first two new user interfaces for Machinekit based on QtQuickVcp:

Machineface
Cetus
These interfaces can be run on the same system that is running Machinekit, or they can be run remotely on a tablet, smart-phone, or standard desktop.  Since the interface is based on Qt, it can run virtually anywhere, including Windows, Mac, Linux, and mobile (Android and iOS).  Alexander posted a video walk-through if you want to see more than just the screen-shots:

See Alexander's post on the Machinekit list if you want to try out one of these interfaces.

Thursday, September 11, 2014

Package Based Install

Alexander Rössler has put together a page showing how to create a Machinekit image for the BeagleBone based on Debian Packages.

The current packages still require absolute paths to the PRU code in your configuration files (sadly, a different path than is needed for the previous run-in-place builds).  I hope to have enough time to address that soon by embedding the PRU code directly into the HAL driver. This will also prevent any possible confusion caused by the HAL and PRU code versions not matching (which I can confirm is a nasty issue to track down if you're not looking for it!).

Package installs also make it much easier to update both Machinekit and the kernel, both of which are "difficult" to update on all of my currently available images.

If you feel up to the task, I strongly suggest switching to a package based install.  It should make it much easier to track ongoing progress with both Machinekit and newer kernels.

Saturday, August 9, 2014

Unexpected Help

While I haven't been doing a lot with Machinekit and the BeagleBone lately ("real" work, kids home from school all summer, family vacation, etc.), the beauty of open source is that anyone who wants to can help.  Out of the blue on Friday, I got emails from github with pull requests for two of my projects:

malcom2073 added details for the PMDX-432 board to my pinmux spreadsheet for the beaglebone

jstampfl added the missing cape-univ-hdmi I've been meaning to write to beaglebone-universal-io

A BIG THANKS to both of you for the help!  I'd also like to encourage anyone else thinking about making a change to an open source project (big or small) to go ahead and do it.  It's a great feeling to help out others, and it lets the owners of the project know people are interested and using the code.

Along those lines, even (especially) if you don't need to change anything but there's a project you're using that "just works", send a quick note of appreciation to the mailing list.  Most first posts are from folks having some sort of problem, so it's always refreshing to get thanks from someone who doesn't need anything else.  Knowing your code is being used and helping others is the sort of feedback that keeps developers happily volunteering their time to write and improve open-source code for everyone to use!

Wednesday, August 6, 2014

New Toy!

OK, "toy" might not be the right word (it's really a powerful tool), but it's just so much fun to play with!  :)

UPS delivered a new controller box for my Probotix Fireball Comet CNC router yesterday.  Unlike the PC version that came with the Comet, this one has a BeagleBone inside and will run stand-alone!

The PC configuration for the Comet is a great example of things you can do with HAL.  The Y axis gantry is is controlled by a single step/dir generator using some HAL logic to split the drive pulses into signals for two separate stepper motors with two independent home switches.  But this approach only works with software stepgen, so something else is needed for "outboard" stepgen that is not directly part of HAL (ie: hm2 drivers and the BeagleBone PRU driver).

I have written a gantry HAL component that mimics the behavior of the Probotix HAL file but works with outboard step generation and up to a seven joint gantry axis.  Testing this with a three-joint gantry axis (my linear-delta 3D printer, temporarily re-purposed as a test-bed) was a lot of fun, but I really look forward to getting this working with real hardware and making some chips.  Look for some example configurations using the gantry HAL component in the near future!

NOTE: In addition to working with standard gantry routers (Fireball, Shapeoko, etc), the gantry component will also work well for other multi-motor axis (like the two-motor Z axis found on many Mendel-style 3D printers) as long as each joint (motor) has it's own home switch.