Archive for May, 2011

It was a fun day, trying to lay out the Panda server cluster again.  With the original design each Panda daughter card mounted the laptop sized HD directly on it.  With the dropping of the daughter card, I had to mount all of the HD’s in external SATA to USB containers, and then make mounts to hold all of them.  That was a success but as you can well imagine it took up a lot of unplanned space.  That space was supposed to hold the large regulated 5VDC power supply, the 12VDC power supply and the remote control relay board.   Ha, no chance of that now. :-/

What to do, what to do?

With lots of moving things around in the box I finally arrived at mounting all three items on the side of the case, looking at it from the front everything is mounted on the right hand side of the case.  I made up templates of each item, put locater holes in each template and then took the side off the case and out to the drill press we go.  Lots of drilling and then filing to remove burrs.  Couple hours or so later, everything mounted cleanly.   Nice, 4 hours rearranging stuff, drawing templates, 2 hours machine and mounting.  Almost an entire day shot.  Still I think it is going to be better then the original design with the daughter cards.

The ongoing saga of the Panda builder, with the design change of no daughter card we needed a way to mount the hard drives into the chassis and connect them to the Panda boards.  Since the Panda only can add HD’s on a USB channel that made the choice fairly easy: Use a USB laptop drive enclosure.  Which leads to the next problem how do you mount an external enclosure that is not meant to be mounted?  Pick up some aluminum 5/8″ U channel and some 1/2″ aluminum angle and get creative with a band saw, drill press, pop-rivets and you get vertical stacking bays that hold 7 drives each.  You can fit 3 across the back of the case, leaving room for cables and such.  Yea.  Only took a full day to fabricate in the Texas heat, but that is another story (lets just say it is amazing just how much water you can drink in the heat).

With the design change of not using daughter boards changed the way the Panda boards are  put together.  The new design has some challenges are where to put the USB Hard Disks.  Really had to save space as we added 2 USB hubs for booting and an extra Panda board.  The Pandas are mounted forward in the case, with the 5vDC and 12VDC power supplies mounted on the side panels, followed by 2 fuse panels and relay control board also mounted to the side panels.

Today will be spent doing physical mounting of the hardware and tomorrow and Monday wiring the hardware up.  Need to order some more connectors and wires as the USB booting adds an extra wire per Panda that was not in the original design and need to bring out the Ethernet and serial port of the extra Panda board.

The pictures show the rough layout, there may be some fine tuning as I try to mount everything in the box.

The Custom Case Arrives

Posted: May 17, 2011 in Hacking, Hardware, ubuntu
Tags: , ,

Yea, back from UDS one day and Fedex showed up at my door with a large box in hand.  It is the custom case for the Ubuntu ARM build cluster.

I open the box and look inside expecting to see a 4U (rack Units or 7″) high,  27″ long 19″ wide rack mount case.  What I actually see is a bunch of loose metal pieces, some nuts and bolts and 3 fans.  What the heck????

Oh I get it, it’s a flat pack like when you buy furniture from IKEA.  It’s a do-it-yourself case, which I guess sort of fits this project as it’s a do-it-yourself cluster of ARM boards. Everything I asked for is where I asked for it to be, I just have to do the final assembly. It’s pretty cool but caught me off-guard. I took some before and after photos.

It came with no hints on how to put the case together but how hard can it be?  It has 2 handles, 2 slides, 2 sides, a front, back,  top and bottom panel right?  Well turns out it’s a tad more complex then that:  The side panels are threaded on one end and have through holes at the other end; the top and bottom panels have one edge bent up at a 90 degree angle and the other end has 3 threaded screw holes instead of the bent angle.  Not that I paid any attention to this before I started.  Got out my tools, my little container of thread lock liquid (I learned a long time ago always use thread lock liquid when assembling things you want to stay permanently together) and began the assembly.

I installed both sides to the bottom panel.  Whoops, I had one side threaded the other not, which I noticed when I attempted to attach the rear to the sides. Confusing to say the least.  With some study I figured out that the 90 degree lip on the top and bottom panels go toward the front of the case, the threaded holes are to mount the back panel.

OK, take one side off, flip it and reinstall.  Now take the front panel handles and find the long screws that are the correct size for the handles.  The screws go through the holes in the side panel, through the holes in the front of the case and into the handles.  OK all good, front panel attached well.  Onto the back panel and then install the fans into the front panel.  Yep you guessed it, it would have been much easier to install the fans first.  Oh well live and learn, the next case I assemble will go much faster.

Well it is that time  again, for those of us who use Ubuntu that is.  It is time for UDS again, this time it’s in Budapest Hungary.  One thing that will be different is that we have a mobile app for Android and the iPhone that lets you access the schedule from your phone.  It’s called Guidebook.  If you are going to UDS and have an Android or iPhone you might want to get it. Goto and you will find out where to get it from.

One word of caution however, if you are not using a local Hungarian phone make sure to only use the UDS  WiFi as International data roaming charges can be STEEP!

I know I know, I’ve not written about the ARM PPA build cluster in a while but it has been progressing slowly.  But the good news is I finally have all 20 Panda boards and most of the miscellaneous hardware I need here.  I am still waiting for a case (it’s ordered) and I’m going to need to find a new person to design a simple circuit board as teh gent that was going to do it fell through (more about that later).  If anyone that reads this is good at circuit board design and wants to do some work, contact me here.  Going to need a small board, 2 or 4 layers designed and manufactured.  I want it to be open sourced so anyone can make them too.  Again more about this in the next posting.

Hope to see you all at UDS. 🙂