The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Oddities

Who’d’a thunk it?

  • Photo Tweakage: Mouse Tunnels in the Snow

    Mouse tunnels in the snow
    Mouse tunnels in the snow

    As the snow cover melts away in the spring, you discover how much activity has been going on.

    The mice make elaborate tunnels with spaces for seed stores, latrines, and numereous secret entrances near the bushes. For a few months, at least, they can scamper all over the yard without worrying about becoming snacks for owls and hawks.

    This kind of picture requires a bit of tweakage, because the default camera settings deliver an essentially gray picture with no contrast. The usual auto-exposure settings assume a more-or-less neutral background, so the camera adjusts the exposure to deliver a neutral result. Unfortunately, you really want most of the background to be white, so the default snow image will be grossly underexposed.

    Set the camera to overexpose the picture by 1 or 2 EV; if your camera has a histogram display, adjust the exposure to put that huge bump on the white end close to the right side of the histogram. It helps if you frame the picture before doing this, as the LCD monitor will be pretty much retina-burn white.

    Take the picture and get it into your PC.

    GIMP Level Adjustment Window
    GIMP Level Adjustment Window

    Now, in your favorite photo-editing software (The GIMP on our desktops), adjust the photo’s levels & contrast. This screen shot shows the logarithmic histogram; the linear one is basically just one peak 3/4 of the way to the right side with a little grass on the rest of the chart. The two little buttons in the upper-right choose linear or log.

    Drag the white point (the teeny white triangle on the right, just below the histogram) until it’s just a bit to the right of the abrupt dropoff’s foot. That sets the whitest part of the picture to real white, not half-a-stop-down light gray.

    You can do the same with the black point (the black triangle on the left), setting it to just left of the black dropoff. In this case, we have some genuinely dark areas, so leave it alone.

    Now, the key part: drag the middle triangle to adjust the gamma. Move it rightward to darken the overall image by decreasing the gamma and emphasize small differences on the bright end of the histogram. That makes the tunnels pop out of the image, although it also tends to make the snow look very contrasty.

    Don’t go overboard with this sort of thing, but a little adjustment can reveal details and bring pictures back to life. It’s not for Ansel Adams quality pix, that’s for sure.

    Here’s possibly more than you want to know about levels & gamma & contrast, but with much better illustrations and more descriptions: Unai Garro’s Blog. He has other useful tutorials, too.

  • A Thorough Job of Hard Drive Data Destruction

    Scrubbed hard drive platters
    Scrubbed hard drive platters

    What’s wrong with this picture?

    A friend rides herd on a college data center and reports that one of the hot spares in a drive array started complaining about errors. By the time he got to it, things had gone from bad to worse to worst: the drive was spinning, but its data was gone.

    He removed all the head frippery before giving me the carcass, but the platters are exacty as they were when he ripped through those “Warranty Void If Removed” stickers.

    Even though disk platters are now made of glass in order to achieve adequate flatness tolerances, you’re not supposed to be able to see through the things. There’s a bare millimeter of untouched plating on the inner and outer rims; everything else is finely ground glass.

    Evidently the drive suffered a head crash or some part of the plating peeled off, after which the debris acted as grinding compound under the heads on the rest of the platters. Eventually the internal filters clogged and the ensuing dust storm scrubbed the glass platters clean.

    He said the inside of the drive was filled with impalpable silvery dust. Another friend deadpanned “Oh, so all the data was still in the drive, right?

    We decided that sorting all those dust grains into the right order would tax even Iranian “students”.

    More than you likely want to know about hard drive platters resides there.

  • Nonmagnetic Tweezers: Don’t Believe The Hype

    A small package of 6000 SMD resistors just arrived from a Hong Kong eBay seller. It showed up promptly despite traveling halfway around the world, had neat packaging, and I’ll give ’em good feedback.

    Also included was a free needle-tip tweezers, just exactly what you need for plucking those little ceramic rectangles from their packages. I  already have a bunch of needle-tip tweezers in my rack, but you can never have too many tools and this one won’t go to waste.

    Gooi TS-11 tweezers
    Gooi TS-11 tweezers

    The package has what appears to be comprehensive instructions in both Chinese and Japanese (to my untrained eyes, anyway). Not much in English, other than that Anti-magnetic, anti-acid and non-corrosive Stainless Steel line; perhaps this isn’t the export model. Indeed, it lacks the obligatory country-of-origin labeling, but, given where the package came from, one may reasonably assume the usual Chinese origin.

    The tweezers are (almost illegibly) stamped STAINLESS NON-MAGNETIC and bear a tidy sticker: gooi TS-11 ANTIMAGNETIC.

    Gooi TS-11 Antimagnetic sticker
    Gooi TS-11 Antimagnetic sticker

    The build quality and surface finish are, um, a bit rough, but Gooi seems really proud of their non/anti-magnetic properties.

    Needless to say, a magnet sticks firmly…

    I have no convenient way to test their anti-acid (whatever that is) and non-corrosive properties, but I’m betting these suckers are plain old Chinese mild steel, made from recycled US scrap. Perhaps the previous iteration was stainless and we’re stepping down the cost-saving ladder? If they would just change the packaging to match reality, that would be fine with me.

    [Insert standard observations about Chinese quality control here.]

    Y’know, come to think of it, I’m sort of wondering about those 6000 SMD resistors. With any luck they’ll actually work when I get around to using them. If not, I suppose it serves me right for buying direct from Hong Kong via eBay, eh?

    And, yes, I know some stainless steel is magnetic.

  • They’re Getting Bolder!

    Turkey on the Patio
    Turkey on the Patio

    Got up this morning, looked out the kitchen window, and there stands a turkey on the patio!

    They’ve been edging closer and closer for the last week or so; we think the snow cover is making the seeds under the feeder look more attractive. As nearly as we can tell, though, they have yet to venture across the patio to the feeder: no tracks in the snow.

    What would be really impressive: a row of turkeys lined up on the patio railing, just like they do on our neighbor’s split-rail wooden fence.

  • Unsolderable Header Pins

    Unsolderable pin headers
    Unsolderable pin headers

    Speaking of things that don’t work, these header pins from my stash have developed some sort of rot. They’re genuine Brand Name pins, albeit a few decades old, and have been stored in the original bag in various basements along the way.

    What’s supposed to happen: you touch a pin with a soldering iron and some solder, the solder melts and wets the pin. If the pin is in a circuit board at the time, the solder bonds it to the pad surrounding the hole. Nothing exciting here, except that when I tried to use these pin headers, that didn’t happen.

    The symptom is that the headers are unsolderable: the solder doesn’t wet the pins.

    Non-solderable header pin detail
    Unsolderable header pin detail

    The detail view shows what does go on. When I touch a the pin, the original solder plating scoots out of the way, exposing the underlying metal (or whatever it is). Neither tin-lead nor tin-silver solder wets the surface, so the pin can’t be soldered.

    The flux forms a layer over the new surface and doesn’t do its usual job of cleaning the metal. Scraping the pin clean doesn’t seem to help, either. In fact, nothing helps: that whole bag of headers is a dead loss.

    I’m sure these things worked when they were fresh, but that was a long time ago. I’m not sure what sort of change could occur underneath the original solder plating.

    So I picked up some new headers with what passes for gold plating these days and they work fine.

    The pix come from my pocket camera on the binocular microscope, using my homebrew adapter.

  • NOAA N-Prime is Up at Last!

    Not that anybody pays attention to these things, but NOAA’s N-Prime earth observatory had a successful launch today.

    There’s a bit of backstory to this bird: Lockheed-Martin manged to drop the satellite during the final phase of its assembly, causing all manner of damage. Basically, they forgot to bolt the booster adapter down before trying to tilt the satellite over.

    It seems L-M ate the rebuild costs, which was a nice gesture on their part.

    I wrote about the event in my Dr Dobb’s Journal column some years back, in the context of how we do error checking in our projects. Bottom line: no matter how good you think your development process might be, alas, you’ll always miss something. The trick is to miss only small problems, not project-killers.

    Now, if only the bird works correctly…

  • Spam Proposition

    This flotsam recently washed over the railing. I added the bold highlight:

    Ladies and Gentleman.

    In order to have your company inserted into the registry of World Businesses for 2009/2010, please print, complete and return the enclosed form (PDF file) to the following address:

    WORLD BUSINESS GUIDE
    P.O. Box 2021
    3500 GA Utrecht
    The Netherlands

    register@ — .biz
    FAX: ++31 — — 8107

    Updating is free of charge

    Treating the attached PDF with the same casual nonchalance I use with any lump of high-level radioactive waste, I opened it in The GIMP (to strip any interesting PDF malware) and found an ordinary printable PDF form.

    Surprisingly, it didn’t have any slots for charge card or bank account info, but, down at the bottom, there’s a dense block of fine print.

    I ran it through pdftotext to get the raw text and here’s the kick in the head, boldified for your reading convenience.

    THE SIGNING OF THIS DOCUMENT REPRESENTS THE ACCEPTANCE OF THE FOLLOWING CONDITIONS AND THE CONDITIONS STATED IN “THE TERMS AND CONDITIONS FOR INSERTION” ON WEBPAGE: WWW.WORLD-BUSINESSGUIDE.COM. THE SIGNING IS LEGALLY BINDING AND GIVES YOU THE RIGHT OF AN INSERTION IN THE ONLINE DATA BASE OF THE WORLD BUSINESS GUIDE, WHICH CAN BE ACCESSED VIA THE INTERNET. A CD ROM WITH WORLDWIDE BUSINESSES IS GRANTED, ALL IN ACCORDANCE WITH THE CONTRACT CONDITIONS STATED IN “THE TERMS AND CONDITIONS FOR INSERTION” ON WEBPAGE: WWW.WORLDBUSINESSGUIDE.COM. THE VALIDATION TIME OF THE CONTRACT IS THREE YEARS AND STARTS ON THE EIGHTH DAY AFTER SIGNING THE CONTRACT. THE INSERTION IS GRANTED AFTER SIGNING AND RECEIVING THIS DOCUMENT BY THE SERVICE PROVIDER. I HEREBY ORDER A SUBSCRIPTION WITH SERVICE PROVIDER INTERNATIONAL DIRECTORIES LTD “WORLD BUSINESS GUIDE”. I WILL HAVE AN INSERTION INTO ITS DATA BASE FOR THREE YEARS. THE PRICE PER YEAR IS EURO 995. THE SUBSCRIPTION WILL BE AUTOMATICALLY EXTENDED EVERY YEAR FOR ANOTHER YEAR, UNLESS SPECIFIC WRITTEN NOTICE IS RECEIVED BY THE SERVICE PROVIDER OR THE SUBSCRIBER TWO MONTHS BEFORE THE EXPIRATION OF THE SUBSCRIPTION. YOUR DATA WILL BE RECORDED. THE PLACE OF JURISDICTION IN ANY DISPUTE ARISING IS THE SERVICE PROVIDER’S ADDRESS. THE AGREEMENT BETWEEN THE SERVICE PROVIDER AND THE SUBSCRIBER IS GOVERNED BY THE CONDITIONS STATED IN “THE TERMS AND CONDITIONS FOR INSERTION” ON WEBPAGE: WWW.WORLD-BUSINESSGUIDE.COM

    I haven’t checked out the full T&C, as I doubt I’ll benefit from such a listing.

    This probably works best in large organizations, where one sucker responds to the spam and then the billing department responds automatically to incoming invoices. The two-month advance notice is a really nice touch, isn’t it?

    Why do people continue to fall for this crap? If it didn’t pay off, the spammers would dry up and blow away, so there must be a fresh crop of suckers every day.

    People, stop doing that!

    Update: More on spam and what (not) to do: http://www.spamprimer.com/