Ed
By turns: tinker, engineer, husband, author, amateur raconteur, recumbent cyclist, father, ham radio geek. So many projects, so little time!
Homepage: http://softsolder.com
Credit Card Services: Loquacity In Full Effect
The friendly, albeit almost unintelligibly accented rep from Credit Card Services had a ten minute conversation with me: 10:35 is a call duration record!
The minimum balance has bounced back to $3500 and they’re touting a 6.9% rate. She was unwilling to discuss exactly how this works before I “qualified” myself, but I was unwilling to reveal my financial details before knowing more about Credit Card Services.
So we went a few rounds…
Somewhat surprisingly, she gave me plenty of contact information:
- Credit Card Services (“We work with [list of big name credit card companies]“)
- Orlando FL
- Callback 888-311-2249 (don’t call it, it’s not a real number)
- Anna Stakovic
- Extension 292
- ID 435
All of it bogus, of course.
Perhaps Anna married into her name, because she has a thick Indian subcontinent accent that wasn’t helped by boiler-room background noise and VOIP dropouts. Correspondingly, I was hampered by a soft voice that often required me to repeat myself, despite speaking slowly and, if I do say so myself, rather clearly.
Anyhow, poor Anna became increasingly frustrated, accusing me of wasting her time and repeatedly telling me that if I was not interested in Lowering My Interest Rates I should just hang up. So I asked her if she worked for the same Credit Card Services that had called me several (dozen? hundred?) times previously; to my surprise, she said it was.
She said that she would “do her best” to remove my number, but that, because she didn’t actually do the dialing, it might not have any effect. That agrees with what I’ve been told before: CCS is actually a demon-dialing front end for other scammers.
She dodged my question about why CCS doesn’t obey the FTC No-Call Registry rules, claiming that she was just qualifying me for a credit reduction, not actually selling me anything. She was unwilling to discuss the relation between CCS and my various card issuers, which might have provided the “prior business relationship” required to work around the rules.
Somewhat surprisingly, she simply wouldn’t hang up before I agreed that I had no interest whatsoever in Lowering My Interest Rates. I eventually agreed, she wished me a good rest of the day, and I suppose we parted as friends…
MOSFET rDS PCB
Posted in Machine Shop, Electronics Workbench on 23-February-2012
This one came out surprisingly well, apart from the total faceplant with that resistor. With any luck, it’ll measure MOSFET on-state drain resistance over temperature for an upcoming Circuit Cellar column; it’s a honkin’ big Arduino shield, of course.
Drilled holes on the Sherline using the relocated tool height switch:
rDS Tester - drilled PCB
Front copper, after etching & silver plating:
rDS Tester - etched front
Back copper, ditto:
rDS Tester - etched rear
I think I can epoxy the resistor kinda-sorta in the right spot without having to drill through the PCB into the traces. Maybe nobody will notice?
The traces came out fairly well, although I had to do both the top and bottom toner transfer step twice to get good adhesion. Sometimes it works, sometimes it doesn’t, and I can’t pin down any meaningful differences in the process.
And it really does have four distinct ground planes. The upper right carries 8 A PWM Peltier current, the lower right has 3 A drain current, the rectangle in the middle is the analog op-amp circuitry tied to the Analog common, and surrounding that is the usual Arduino bouncy digital ground stuff. The fact that Analog common merges with digital ground on the Arduino PCB is just the way it is…
EAGLE Library: 10 W Aluminum Power Resistor
Posted in Electronics Workbench, Software on 22-February-2012
It appears there are at least two different 10 W aluminum resistor sizes: the one used by Dale and the one used by everybody else. It’s either that or the EAGLE HS10 symbol is wrong…
Using those dimensions, here’s a part that more closely fits the resistors in my heap. EAGLE 6 uses an XML file format, so you can stuff some ASCII text into the appropriate sections of your custom.lbr file (or whatever).
The EAGLE package, which remains HS10 as in the resistor-power library, should produce something that looks like this:
EAGLE 10 W Resistor package
The XML code includes top-keepout rectangles under the body footprint:
<package name="HS10"> <description>DALE Power Resistor 10W</description> <wire x1="9.525" y1="5.461" x2="9.525" y2="10.3378" width="0.2032" layer="21"/> <wire x1="9.525" y1="10.3378" x2="4.6482" y2="10.3378" width="0.2032" layer="21"/> <wire x1="-9.525" y1="-5.461" x2="-4.6482" y2="-5.461" width="0.2032" layer="21"/> <wire x1="-4.6482" y1="-5.461" x2="9.525" y2="-5.461" width="0.2032" layer="21"/> <wire x1="9.525" y1="-5.461" x2="9.525" y2="5.461" width="0.2032" layer="21"/> <wire x1="9.525" y1="5.461" x2="4.6482" y2="5.461" width="0.2032" layer="21"/> <wire x1="4.6482" y1="5.461" x2="-9.525" y2="5.461" width="0.2032" layer="21"/> <wire x1="-9.525" y1="5.461" x2="-9.525" y2="-5.461" width="0.2032" layer="21"/> <wire x1="4.6482" y1="5.461" x2="4.6482" y2="10.3378" width="0.2032" layer="21"/> <wire x1="-9.525" y1="-5.461" x2="-9.525" y2="-10.3378" width="0.2032" layer="21"/> <wire x1="-9.525" y1="-10.3378" x2="-4.6482" y2="-10.3378" width="0.2032" layer="21"/> <wire x1="-4.6482" y1="-5.461" x2="-4.6482" y2="-10.3378" width="0.2032" layer="21"/> <wire x1="-9.47" y1="0.5" x2="-17.78" y2="0.5" width="0.2032" layer="51"/> <wire x1="-17.78" y1="0.5" x2="-17.78" y2="-0.5" width="0.2032" layer="51"/> <wire x1="-17.78" y1="-0.5" x2="-9.47" y2="-0.5" width="0.2032" layer="51"/> <wire x1="9.47" y1="-0.5" x2="17.78" y2="-0.5" width="0.2032" layer="51"/> <wire x1="17.78" y1="-0.5" x2="17.78" y2="0.5" width="0.2032" layer="51"/> <wire x1="17.78" y1="0.5" x2="9.47" y2="0.5" width="0.2032" layer="51"/> <pad name="1" x="-15.24" y="0" drill="1.3" shape="octagon"/> <pad name="2" x="15.24" y="0" drill="1.3" shape="octagon"/> <text x="-6.35" y="1.27" size="1.27" layer="25">>NAME</text> <text x="-6.35" y="-2.54" size="1.27" layer="27">>VALUE</text> <rectangle x1="-9.779" y1="-5.715" x2="9.779" y2="5.715" layer="43"/> <rectangle x1="4.318" y1="5.715" x2="9.779" y2="10.668" layer="43"/> <rectangle x1="-9.779" y1="-10.668" x2="-4.318" y2="-5.715" layer="43"/> <hole x="-7.1374" y="-7.9375" drill="2.3876"/> <hole x="7.1374" y="7.9375" drill="2.3876"/> </package>
The EAGLE symbol looks just an ordinary schematic resistor:
<symbol name="RESISTOR"> <wire x1="-2.54" y1="0" x2="-2.159" y2="1.016" width="0.2032" layer="94"/> <wire x1="-2.159" y1="1.016" x2="-1.524" y2="-1.016" width="0.2032" layer="94"/> <wire x1="-1.524" y1="-1.016" x2="-0.889" y2="1.016" width="0.2032" layer="94"/> <wire x1="-0.889" y1="1.016" x2="-0.254" y2="-1.016" width="0.2032" layer="94"/> <wire x1="-0.254" y1="-1.016" x2="0.381" y2="1.016" width="0.2032" layer="94"/> <wire x1="0.381" y1="1.016" x2="1.016" y2="-1.016" width="0.2032" layer="94"/> <wire x1="1.016" y1="-1.016" x2="1.651" y2="1.016" width="0.2032" layer="94"/> <wire x1="1.651" y1="1.016" x2="2.286" y2="-1.016" width="0.2032" layer="94"/> <wire x1="2.286" y1="-1.016" x2="2.54" y2="0" width="0.2032" layer="94"/> <text x="-3.81" y="1.4986" size="1.778" layer="95">>NAME</text> <text x="-3.81" y="-3.302" size="1.778" layer="96">>VALUE</text> <pin name="2" x="5.08" y="0" visible="off" length="short" direction="pas" swaplevel="1" rot="R180"/> <pin name="1" x="-5.08" y="0" visible="off" length="short" direction="pas" swaplevel="1"/> </symbol>
And then the EAGLE resistor device lashes everything together:
<deviceset name="R" prefix="R" uservalue="yes"> <description>Resistors</description> <gates> <gate name="R" symbol="RESISTOR" x="0" y="0"/> </gates> <devices> ... many more devices... <device name="ALUM-10W" package="HS10"> <connects> <connect gate="R" pin="1" pad="1"/> <connect gate="R" pin="2" pad="2"/> </connects> <technologies> <technology name=""/> </technologies> </device> ... many more devices ... </devices> </deviceset>
Update the libraries and then it should Just Work.
It would have been much better had I discovered this before drilling & etching the board with one of those resistors…
Basement Safe Humidity: The Trend Continues
Posted in Home Ec, Machine Shop on 21-February-2012
The desiccant in the basement safe:
Desiccant in safe
Continues to work just fine, much better than the first attempt:
Basement Safe Humidity - 2012-02-06
The paper scrap gives the weight of tray+desiccant, so when the humidity finally starts going up I’ll have some idea of the average leak rate. Most likely, opening the door for the more-or-less monthly logger readout introduces most of the water vapor…
Tweezer Tip Alignment & Shaping
Posted in Home Ec, Machine Shop on 20-February-2012
During a recent rainstorm I grabbed the fiberglass marker pole at the end of the drain pipe to clear a wad of leaves out of the driveway gutters. Unfortunately, that left me with a finger full of glass fibers; it seems the top of the pole has deteriorated. The first tweezer I plucked from the stash around the pencil-oid tool holder hadn’t had its jaws aligned, so after I plucked (most of) the glass using those tweezers, I did a bit of filing and sandpapering:
Tweezer tips
That’s a millimeter scale in the background: these really are needle-tip tweezers.
A closer view:
Aligned and shaped tweezer tip
It still has a bit of overbite, but it grabs hairs from the bench with no hassle. Given that you can’t get all the glass fibers on the first pass, it’ll come in handy…
DIY Vanilla Extract: Batch 2
So I picked up half a pound of Grade B Madagascar Vanilla Beans from the usual eBay supplier, a 1.75 liter slug of the next-to-the-cheapest 80 proof vodka (“carefully distilled, then filtered through selected charcoal”) from the neighborhood liquor store, and scavenged some bottles from the basement stash:
Vanilla extract bottles
The proper mix seems to be around 2 ounces of beans per 16 liquid ounces of 80-ish proof vodka, which nearly fill the two round half-liter (16.9 fluid ounce) bottles. The flat bottle on the right has the rest of that Devil’s Spring 160 proof rotgut, cut down to 90 proof, with enough beans to make the answer come out right for that volume. The leftmost round bottle has the remainder of the beans in the appropriate volume, which is why it’s half full. The little bottle is that one, minus doses for my hot chocolate & pancakes.
One motivation for using 80 proof vodka is that a teaspoon of 160 proof hooch brings a cup of hot chocolate right up around 3 proof. That earlier batch really didn’t have enough vanilla to be effective, but increasing the total dosage would put a dent in my already meager afternoon productivity…
Although the recipes recommend daily shaking for a month before the brew reaches equilibrium, I’m sure this is one of those exponential diffusion deals that’s mostly done after a day or three. These two bottles show the concentration on the next morning, after and before shaking:
Vanilla extract - shaken and unshaken
Chopping half a pound of vanilla beans on the kitchen cutting board produces an interesting side effect: everything you cut for the next day or so smells strongly of vanilla, as does the entire kitchen end of the house, as do your fingers. Mostly, that’s OK, but we decided vanilla-scented onions were just plain weird and there really isn’t any justification for vanilla-flavored green tea.
Kitchen Hazard: Exploding Potato!
It was such a small potato that it didn’t need a nail and, somehow, didn’t get punctured before going into the oven. When it came out, the first touch of the fork detonated the thing:
Exploded Potato
Memo to self: always puncture potatoes before baking!
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