Interesting Tech Projects
Linux
Updates
Oct 24th
I found out that the linux-rt kernel is not suitable for running EMC2/LinuxCNC. Sorry if you followed those steps. You can remove it using sudo apt-get remove linux-rt. Instead the kernel must be patched with RTAI. I’m currently working out the correct steps to do this. So far I tried the pre-built kernel in the Gutsy experimental folder but ethernet was broken. I don’t recommend bothering with those packages. Instead I hope to come up with the steps to install EMC2/LinuxCNC manually.
I have received most of the parts for the 24VDC, 10A power supply that is needed for the HobbyCNC board. Once I have that completed I will post a complete bill of materials with Digi-Key part numbers.
I damaged once of the stepper drivers on my HobbyCNC board while performing some simple tests with a bench power supply I have. The motor was connected incorrectly. Now I have to order a replacement. Luckily I was testing only one axis, otherwise I could have damaged all the drivers.
As you can see slow progress is being made on several fronts. Hopefully I will have something concrete to post soon.
Ubuntu Splash Screen
Oct 22nd
Well…the splash screen was not centered. I think this was because the installation detected my monitor as “generic plug and play” with more limited capabilities than it really has. I changed the display settings in Gnome so I can get 1152 x 864 at 75Hz, but this left the splash screen off center. Here is the fix:
Edit /etc/usplash.conf to set the correct x and y resolution.
Run: sudo update-initramfs -k all -u
The update-initramfs needs the “-k all” option to update all kernels. In my case I have the generic and real time kernels.
Linux Real-time Kernel Installed
Oct 19th
EMC2 requires a real-time kernel (which Windows XP and Vista are not). Installing it on Ubuntu 7.10 was pretty simple.
- Open a terminal window
- Run
sudo apt-get install linux-rtand wait - Reboot
After the PC rebooted Gnome complained that the theme manager wasn’t working. Another reboot fixed that problem. Running:
uname -v
gives:
#1 SMP PREEMPT RT Mon Oct 15 01:05:51 GMT 2007
So the real-time kernel is now installed and working. I will play around with the desktop for a while to make sure it is stable before proceeding further.
Ubuntu 7.10 Gutsy Gibbon
Oct 18th
Today the latest version of Ubuntu was released – version 7.10. I am hoping to use this with EMC2 a.k.a. LinuxCNC for controlling my CNC machine. Why? Because Linux offers a real time version of the Kernel. The alternatives are Windows with Mach2/3 (which is not free) or DOS and TurboCNC (also not free). Windows is not a real time operating system, so the only software that works properly has to code around this. As far as I know that is the Mach programs. I will still need Windows however for DXF and CAM applications.
Downloading Ubuntu from the mirrors was painfully slow, and attempting to using the official torrent file resulted in “connection refused”. I presume a large number of people are also downloading the OS today. So I used the torrent file on this page. I pulled down the ISO image in two hours. Not bad. Burnt it to CD, added a second hard drive to my desktop PC (not required, but I chose to do it this way), created an image of the Windows partition and booted with the CD in. The install was pretty smooth. Only a couple of glitches. Grub failed to boot because I needed to enable the second drive in the BIOS. And the package manager decided to not install anything, which was quickly solved with this information in this thread.
Hopefully I will be able to get the real time kernel and EMC2 installed. If so I will post instructions, otherwise I will probably have to switch to 6.06 a.k.a. Dapper Drake.
