Tuesday, December 30, 2008

PC Building

Well, my wife asked me to build a PC for her for her prethesis/thesis work. Needs to run Autodesk Revit 2009 and Photoshop CS 2/3/4 as best as possible. We're sticking with Windows XP. Things I've found out so far:

1) Photoshop likes 1 or 2 cores, and a fast scratch disk
2) Hardware RAID5 for the main OS partition may be nice but is a real no-no if you want to migrate hardware in the future.
3) Revit 2009 will use up to 4GB in Vista (3GB in Windows XP) and one core for design work. Rendering, however, will use up to four cores.

So, this is what I'm looking at

Case: Antec Sonata III with 500W PSU
Hard Drives: 2x 1 TB Western Digital Caviar Black plus 1x 150GB Velociraptor
ROM: Any decent DVD burner (no bluray)
Video: ATI FirePro V3750 256MB
Display: still looking, probably a 24" LCD

Now, I haven't detailed my motherboard/cpu/ram choices yet. I'm going to have to determine how I want to tackle this:

Option 1a:
4GB (2x2GB) DDR3 1333 (~$100)
Core2 Duo 3.33GHz (~ $270)
MSI P45-8D LGA 775 Intel P45 ATX Intel Motherboard (~ $150)

Option 1b:
Substitute Core2 Quad 2.86 GHz (~$320)

Option 2:
6GB (3x2GB) DDR3 1333 (~$150)
Core i7 920 2.66GHz Quad Core (~$300)
GIGABYTE GA-EX58-UD5 LGA 1366 Intel X58 ATX Intel Motherboard (~$300)

Cost goes up and you go down the list. Option 1a is good but may be limiting in the future. Option 1b is more future proof but still not the newest technology. Option 2 is the bottom of the newest tech, which has too much RAM for XP, but I want to try to get the triple width memory controller working and it has somewhere to go with a future upgrade. It's somewhat slower, though, on single threaded applications. It's also the bottom of the pile for the processors.

Does Windows XP 64bit have issues with 32 bit applications? This would make the 6GB of RAM worth it. $140 for XPPro or XPPro64.

System layout is to put everything on a mirrored 1GB hard drive array. I originally wanted a RAID5 array, but I understand how bad that can be if you put your OS on that array. I'm not buying 5 hard drives to do that right now! The Velociraptor is for windows swap, Photoshop scratch, and general high speed mayhem. If I switch motherboards to something with an integrated SAS controller, I might swap out for a 15Krpm Fuji drive. Price is the almost the same incidentally.

The fish tank is on hold until the kitchen cabinetry is finished.

Sunday, December 28, 2008

RepStrap/Mill combo?

Looking around, found this:


A stiff but glorified dremel tool. Good design and heritage though. Make a 3 axis CNC and attach an extruder head and off we go! Still researching this little 100W spindle machine though.

Monday, December 15, 2008

Linear motors: a little thought

I was doing a little looking at linear motors. Got an idea that it would be a great replacement for the geartrain of a homemade airsoft or Nerf gun, plus I've always been looking at how to build them. I'm focusing on the tubular variety instead of the linear rail as I believe these will be easier to build with minimal components, but I suspect they're either harder to design or build with, as there are two major manufacturers making them, Copley Controls and California Linear Devices.

Construction notes:

First, I've been researching the shaft. From what I can tell, it looks like the magnets are placed end to end, NS-SN-NS and held together mechanically. I'm looking at using a stainless steel sleeve with a series of high energy rare earth cylinder magnets inside with spacers. Down the center will be a possible sleeve and a threaded rod. I'm not certain of the material yet. I'll need a jig to hold the magnets on the rod, then nut each end. I plan to custom cut some aluminum end blocks to suspend the magnets in the middle of the sleeve, and provide me with some semi-disposable ends to mount hardware to.

So far, if I build my first arrangement, I think I'll use this:


They're not the largest or the strongest grade, but this should keep the cost down, too. I'd like a higher strength and temperature grade, but I'd settle for a higher temp grade. Well, one thing at a time.

I've found both online and at my local American Science and Surplus good supplies of small gage magnet wire. I need bobbins to spin this on. Modern stators are often made of steel, but I'm considering building a modular "coreless" coil system to drive this. I might be able to build these as plastic bobbins to wind the coils around and possibly use to hold everything together. I'd probably still dip the coils in epoxy (probably thin fiberglass resin). I have a lot of research to do on this. The hope is to fit all this into an aluminum tube to protect, align, and provide a heat sink.

I also have to find and do some calculations to determine what power/drive I can do. I want to look at 12 or 24V power systems, not 180V DC buses (120VAC). Probably too dangerous. But this means high current, large conductor systems. I need a motor design guide for brushless motors.

I'll also have to have a module to hold the sinusoidal hall effect sensors. Still lots to look into, let alone building a drive module.

Tuesday, December 09, 2008


No, not building a cat. My house now holds three (3) cats. two are bossy, one is incredibly pushy, and will eat the other cats' food. The one that's mine is a pushover and may not get all his food. My wife and I have been talking about a food dish control box using collar tags. I've been prototyping this a bit lately in my CAD program. It's simple and needs one or two switches and a small DC motor. End limit switches, a timer, and a safety slip-friction drive to the cover open and closed safely

Electronics wise I'm thinking an RFID system. Sparkfun sells some all-in-one readers that look to be easy to work with. I'm considering an ID-2 with a custom antenna wound around the base of the unit. Tie this to a simple PIC doing pattern matching. If it constantly sends out, keep the dish open until clear. If it only sends on initial read, close on wrong read. A simple H bridge. I could option in a Zigbee system if I wanted to track data on a PC somewhere.