Luggable PC PSU Layout

To help optimize arrangement of Luggable PC components, I sketched them out in Fusion 360 so I can experiment with layout in CAD space. I was able to find the specification for the ATX motherboard and power supply, which allowed me to use official dimensions. Unfortunately I wasn’t able to do the same for the PCI-Express cards, because I needed to be a member of the PCI SIG to access the official specs. So I measured and guessed dimensions from the specific implementation I have on hand.

Power Supply Unit (PSU)

As the heaviest single component, I wanted the PSU at the bottom so the overall system is not top-heavy. The question is then: which way to orient the PSU? There were two considerations:

  1. PSU cooling intake: The standard ATX case layout places the PSU at the top of the case, drawing air from beneath. I can’t do that with the PSU at the bottom since a downward-facing intake would be blocked by the table surface. I tried the upward-facing intake once, in the Mini-ITX “Easel Frame 2.0” design. That turned out to be a bad idea because every time I dropped something (usually a screw) it would fall inside the PSU and I have to retrieve it to avoid short-circuiting the internals.
  2. PSU wiring: One side of the PSU takes the standard IEC AC cable. The opposite side is where all the DC wires go to the rest of the components. The decision is then whether to point them front-back or left-right. I didn’t want either of them to point towards the user, so I went with a left-right orientation for the wiring.

Taking care of those two considerations leave two good orientation for the PSU. One with the cooling intake facing front towards the user, or facing away from the user. In the current design, facing backwards allows an unobstructed air path so that’s the preferred position today.

Next post: Positioning the motherboard.




Luggable PC Gets Fancy Screen

closelidThe latest iteration of the home built luggable computer gets a fancy rotating screen to protect the screen while in transit and hold the screen up while in use.

The time pressure of making it ready for show-and-tell at the February Hackaday LA meet meant I hadn’t been documenting my lessons learned here.

Which is a shame, because there were quite a few 3D printing lessons learned while building this thing. I briefly mentioned a few of them on the project log update up on but I intend to find the time to expand on those ideas as future posts on this blog. I just hope I can get them all written down before I forget.

Sheet Metal as Sign of Competition

Onshape sheet metal visualization

I’m personally comparing use of Onshape vs. Autodesk Fusion 360, seeing which one I prefer to use for my own projects. As I wrote earlier, each of them offer something I would miss if I started using the other exclusively.

In a close competition, everybody would learn from everybody else and the most important user features will propagate through all the offerings in the market. I wasn’t sure if the people behind Onshape and Autodesk Fusion 360 saw each other as competitors, but now I’m fairly confident that they do and are keeping an eye on each other.

The proof: Sheet metal.

Autodesk Fusion 360 sheet metal preview

Onshape just unfolded their sheet metal feature. (“unfolded” their joke, not mine…) Autodesk said theirs is in a closed invite-only technology preview coming soon to all users. Such a similar feature introduced within a few weeks of each other might merely be a coincidence, but I doubt it. It certainly looks and sounds like they’re working to reach parity with each other’s features.

Additional proof: Constraints

Last time I wrote about the fact Onshape does a great job with constraints, letting the user know exactly where they stand in a way that Fusion 360 does not. At the time I didn’t know Fusion 360 has constraint visualization available as a “preview feature” that is turned off by default.

It is a good step forward for Fusion 360. As of the current preview, Onshape still holds a significant advantage in user friendliness, but the mere presence of the preview assured me that it’s on Autodesk radar and they’ll keep working away at it.

I like the progress I see so far. Competition making everybody better, and consumers win.

Fusion 360 vs. Onshape, Round 1

fusion-360-logo31Since completing the Udemy overview of Autodesk Fusion 360 a few days ago, I’ve started working on a project to get hands-on experience. Here are the items which made the strongest impressions after my first few days:

Advantage: Autodesk Fusion 360

UI Responsiveness: As an application executing locally, it is vastly more responsive to my actions than Onshape executing across the internet.

Integrated Assembly: In Onshape, parts are created in Parts Studios tabs and put together in a separate Assembly tabs. Parts need to have designated “mate connector” added to their designs before the assembly can occur. I never got the hang of this system. In contrast, every Design window in Fusion 360 can import parts from other designs without special entities like mate connectors.

Advantage: Onshape

Constraints: Onshape is really good about informing the user of constraints. Sketch entities are blue when they are under-constrained. When they are properly constrained, they turn black. When they are over-constrained, the conflicting constraints are all highlighted in red.

In contrast, Fusion 360 makes no distinction between under and properly constrained. My only indication an entity was under-constrained is long after the fact, when it would move unexpectedly in response to a change elsewhere. When over-constrained, a dialog box tells you the latest action causes over-constraining, but it doesn’t show you the conflicts so you’d have to go hunting for conflicting constraints yourself. This is a lot of lost time and a huge drain on productivity.

After a week of Fusion 360, this is the Onshape feature I miss the most.

UI scaling: Browser makers have lots of practice dealing with variable sized content on variable sized screens. Running Onshape in a browser window at 4K resolution was painless. In contrast, Fusion 360 scales poorly on a 4K screen, leaving many UI elements tiny and difficult to use.

Other Notes:

Sharing: Onshape free tier users are not allowed private documents, so every file is automatically shared with the world. Fusion 360 was designed for a world with designers and customers and clients, so it has a bunch of tools to manage access and permissions. In all that complication, they seemed to have forgotten to include a simple “share with the whole world” option.

Updates: Both of them update frequently. While it is easier to pick up an update in Onshape (refresh the browser) the Fusion 360 auto-update has been fairly seamless so far.

Udemy: Product Design in Autodesk Fusion 360

udemylogoTalking with some people at the Hackaday meet taught me that there are some real fans of Autodesk Fusion 360. It was already on my to-do list to evaluate the software, but the enthusiasm pushed it to the foreground.

The first frustration is learning the software. All the resources I found are in the form of tutorial videos. I personally prefer information in written text format, but I’ll watch the videos if I have no alternatives. The videos on Autodesk’s own site is built using a Flash-based video system. I avoid Flash when I can, so as an alternative I chose the course titled Product Design in Autodesk Fusion 360 from idea to prototype.

The quality of the course was uneven: different sections in the course were recorded by different instructors each with their own style. Fortunately, the introductory and starting sections about content creation were pretty good, teaching me Fusion 360 basics and then how to create a design. (Sections 1 through 3)

Where these sections fell short was teaching me how to fix problems. That is, beyond hitting Control+Z immediately after a mistake. I know I’ll change my mind on certain design decisions and need to adjust the file later. The class didn’t spend much time over the editing tools and I felt this gap would prove to be a hindrance to my productivity.

Section 4: Rendering, animation, and drawings were very perfunctory and barely enough to get me started. If I actually want to make use of these features, I’ll need to find additional education before I can be proficient.

Section 5: Computer Aided manufacturing(CAM) assumed the student is already familiar with machining and wanted an overview on how to use their existing knowledge inside the Fusion 360 UI. If the student didn’t already know CAM, the section would make no sense.

I think I picked up enough basics for me to start poking around on my own to fill in gaps in my knowledge, so it worked well enough as a brief overview. I’m just a bit disappointed because my expectations were higher.