Archive for April, 2010

On Schematic Capture and PCB Layout Programs

This useful comment thread showed up in relation to a post about a chainsaw repair, which would hide it from any rational collection of search terms. Here’s the thread in all its glory, as there doesn’t seem to be a way to move comments from one post to another.

Feel free to continue the topic in the comments to this post…

randomdreams

Offtopic: have you ever used gEDA for schematic or pcb? I’m looking for something with reasonable abilities, and the crippled demo versions of orcad, eagle, and winqcad all look fairly crippled. I’ve zero use for autorouters and autoplacers (because they suck for analog design) but it’d be nice to have something that’s fairly usable for schematic and layout.

Ed

used gEDA for schematic or pcb?

Nope. Every time I’ve looked at it, the status seems to be heartbreakingly close to being useful by someone who really doesn’t want to work around a morass of limitations. That’s becoming less true and maybe by now it’s practical… but I haven’t done a serious examination for maybe a year.

I actually coughed up half a kilobuck for the Standard version of Eagle schematic & layout, as an autorouter doesn’t do much for the little bitty boards I build. Works fine, no complaints, but if I weren’t doing columns and suchlike, it’d be hard to justify.

Neal H.

andomdreams,

I have used it for both a small project and a slightly bigger project,
http://www.instructables.com/file/FPCHBLIG1M2BQTH (schematic)
http://www.instructables.com/file/F6SYDYYG1M2KI8M (render of layout)

It is quite usable, but the version that ships with most linux distros is pretty old, I had much better luck building it from source following the instructions on the gEDA homepage. The hardest part is creating symbols for the PCB tool, that is a little tricky to learn, but there are a lot of them pre-created for you on gedasymbols.org.

randomdreams

Thanks to both of you. I’ll probably give it a run. I currently spend much of my day creating symbols for Cadence, and I consider it impossible for any other part-creation process to be as painful or difficult as that. I’m more worried about general usability. Eagle’s the back-up plan.

John Rehwinkel

I still haven’t found a PCB layout program I like (and I’ve gotten tired of the truly primitive one I wrote 20 years ago). For schematics, I use DesignWorks Lite, which is apparently no longer offered (though DesignWorks Professional is still available).

John Rehwinkel

Ah, it is still offered (only $40), just not at the main Capilano site. The companion PCB layout program is Osmond ($200), which I keep meaning to try out. You can download the trial version at designworks4.com.

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Monthly Aphorism: On Supplies

  • Never put a part back in the supply cabinet

The Great Green, another excellent manager from my IBM days, mandated that very simple stockroom rule.

He knew, even if we didn’t, that the next engineer would spend two days figuring out that the part you returned was defective, costing far more in the long run than just tossing the part.

Of course, we never tossed the parts…

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Stove Knobs: Index Marks

Reflective index markers for stove knobs

Reflective index markers for stove knobs

The black knobs on our black-front Kenmore stove have slightly raised pointer extensions. At a glance, you cannot tell whether the knob points upward to OFF or downward to 5.

Oddly, the oven temperature knob has a nice white index line engraved (well, molded) in the pointer extension. So it’s not like they didn’t know how to do index lines. I’m guessing they had to take a buck out of the build cost and omitting four index lines added up to just the right amount.

I added tape markers shortly after we got the thing. The previous tape was fluorescent orange; the adhesive lasts several years before turning gummy. These new markers are snippets of outdoor-rated retroreflective tape and should last longer.

Run the knobs through the dishwasher occasionally to get ‘em nice & shiny. Surprisingly, that doesn’t seem to bother the tape.

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Sideways Cyanoacrylate Glue: Bad Idea

Super Glue Tube

Super Glue Tube

I keep all my various adhesive & lubricant tubes standing on their nose or tail in a can, so as to avoid smashing them underneath something else.

This one got opened for a project (the previous tube’s contents having turned into gum) and wound up on the Electronics Workbench overnight. That was long enough for a few drops of glue to leak out of the (I thought) securely tightened cap and wick along the length of the tube against the workbench.

You can’t tell by looking, but that tube is glued down tight.

I managed to chop the tube off the workbench using a stiff scraper, at the cost of a small nick near the top. Even though it’s now sealed with some flexible caulk, it’ll be gum before I need it next… but it won’t leak, because it’s sitting on its tail in a can.

Drat!

FWIW, the workbench surface is leftover laminate flooring from the kitchen / laundry room reflooring project. Works great and should last basically forever.

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McCulloch Chainsaw Handle Repair

Shaped bolt head

Shaped bolt head

We acquired a McCulloch chainsaw from a friend in “Used to worked fine” condition. I hate small internal combustion engines, two-strokers in particular, but sometimes ya can’t look a gift horse in the orifice.

Anyhow, the only real repair needed was a new bolt for the anti-kickback clutch handle. For unknown reasons, McCulloch uses a non-standard head that, fortunately, can be carved out of a stock bolt.

Reshaped bolt in place

Reshaped bolt in place

I got the two parallel sides a bit closer together than was required; if I were to do it again I would squish some modeling clay into the recess, make some measurements, and get it right the first time. I’m certain the original was much fancier, but this will suffice.

Nylock nut on trimmed bolt

Nylock nut on trimmed bolt

Trim the bolt to fit and a nylock nut on the outside should hold it in place forever more.

The repair was prompted by a late winter storm that dropped a huge branch from our neighbor’s tree next to the house. We’d splurged on underground utilities when we upgraded the service entry to 200 A and this is exactly why…

[Update: A great and completely off-topic discussion about schematic & PCB programs showed up in the comments. I've extracted those into a separate post so folks can actually find the discussion with a sane set of search keywords...]

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Running the AADE Filter Design Program in WINE

This requires a bit of hocus-pocus, all of which you can find by diligent searching. Nothing original here, but I’m sure to need it again one of these days.

To install THREED32.OCX:

winetricks mfc40

To fix the “ActiveX component can’t create object” error, you can try the process described there. It didn’t work for me, but one of the messages points out that the error is tied to the nag screen, which will vanish after 10 (?) iterations. That worked, although I admit to losing track of the number of crashes.

Alas, the Help function crashes with that same message while trying to invoke the HELP menu item; the crash brings down the entire program. So it goes.

Anyhow, in the process of figuring that out, I fetched the msscript.ocx file from the Windows installation on this box:

sudo mount -o ro,uid=ed /dev/sda2 /mnt/part
find /mnt/part/WINDOWS/ -iname "msscript*"

Which reports it’s located at:

/mnt/part/WINDOWS/system32/msscript.ocx

Copy it locally for convenience:

cp /mnt/part/WINDOWS/system32/msscript.ocx ~/.wine/drive_c/users/ed/My\ Documents
sudo umount /mnt/part

Then you can register the control:

regsvr32 ~/.wine/drive_c/users/ed/My\ Documents/msscript.ocx

The program entry shows up in the “Other” category of the XFCE menu structure. I added a launcher and eventually found the icon:

~/.local/share/icons/32ce_filter.0.xpm

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Too Many Deer: Another One Bites The Dust

One Less Deer

One Less Deer

Sat down for some tech reading in the Comfy Chair one morning and spotted a lump near the road, at the foot of the deer crossing warning sign.

While I don’t know if this deer was one of that group, it’s a fair bet.

There was no freshly smashed glass or broken plastic in the area, which indicates a relatively low-speed collision, the kind where the deer’s legs snap against the bumper and the body rolls over the hood, crushing sheet metal and deforming plastic frippery along the way.

Many cars display that kind of damage around here. They look as though somebody walloped them with a huge sandbag, which is pretty much the case.

The animal huggers seem strangely silent about such events. If they had the courage of their convictions, they’d subsidize drivers (and gardeners) affected by the deer overpopulating the area. But, no, they never offer to do that.

I did find this in the driveway across the street…

Deer Whistle

Deer Whistle

Before equipping your car with such gimcrackery, read that.

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