Here's my 12 parallel resistors from the last log. Yeah, it's a bit ridiculous ;)

And... all them (series!) crimps may be adding to the unexpected resistance of the last log. Oh well.

I've become a bit [too?] fond of barrel-crimps, recently. Aided by the fact Fry's had a deal which wound me up with a huge stockpile and variety, nevermind a bunch of surprising-quality sorter-boxes, for $4. (And, I've taken to investing in wire from extension-cords at DollarTree. One Dollah!)

So, then comes the next endeavor. My "antPC" (thanks buddy!) runs off 5V. So why run a 5V wallwart off 120VAC if I have 12VDC already? This is more than just an efficiency thing, when the voltage drops too low, my inverter just kicks out without warning. This is especially a concern when starting the engine (e.g. for heat, or a battery-top-up). Not the sorta thing you want happening in the middle of software devel... (nor, maybe, is seeing your breath).

So, I found a car-outlet 5V 6.8A USB "charger"... $9 for, really, a high amperage DC-DC converter, not bad. Especially considering I didn't have to order it. I figure since it's buck (rather'n boost) it probably will work even if the battery's *severely* drained. And, tests show it does, at least, keep running after the inverter conks out. So, when that happens, I guess, a little warning to properly shut-down, or start up the ol' engine.

This isn't just for the computer, though... Remember what this project was about? Yeah, I almost forgot, too. My floppy drive runs off 5V, as does (for now) the uC/circuit, programmer, etc. AND, I got a USB DVD drive at Goodwill, $5, so can finally add a few new movies to my viewage. AND I managed to salvage my old lappy's hard disk with a USB SATA adapter...  (Thank goodness!). Both the DVD and HDD take more power than the antPC's USB ports provide, so 6.8A does the job of powering the antPC and the drives through a powered hub.

Here's a teardown of the charger. Pretty simple, really. And not too difficult to hack for my needs. 12V in, 5V out, (handy they had two boards with wire inbetween!) and some extra powered USB ports for "Dumb" things like the floppy-drive or phone charging.

(BTW, it's a Hypergear "Quad USB Car Charger" 12-24V in, 5V 6.8A out)

Had some challenges to overcome. 

Like I said, I've become maybe too fond of these crimps. I started soldering when I was six. That *would* be my de-facto wiring technique. But, the solder-station is no longer always at-the-ready. So... carried-away with crimping.

First challenge: the 5V wires are too skinny to crimp. And too short to strip really long and fold-over a few times. Too short, really, to even twist with some additional stranded wire. Too short to twist around a solid wire. Yep, I really thought this through.

I'm actually quite proud of my solution. Wrap solid wire around it, like wire-wrapping. The solid wire is nearly perpendicular to the thin stranded wire we're crimping, so pull-out shouldn't be a concern. I tightly-wrapped two layers, then crimped. Rather, it's not particularly tight around the stranded-wire (that'd've just bent it!) but that each winding is tight to the next.

Worked so well, I did it four times.

("WTH, man? Just solder a new longer wire!")

Oh yeah, and it's too short to leave the insulation sleeve full-length. Another thing I ran into several times.

(Hey, note, I wouldn't be nearly so gung-ho about these crimps if I had a cheap non-ratchetting tool. I bought a cheap ratchetting one a while back. I think it was $15. It's really worth it. If just to prevent blistered palms. But, really, a ton of reasons.)

The next step was getting permanent wiring to the 12V... I'm sorry, but "cigarette lighter" outlets are stupid. Is there any plug that doesn't eventually push itself out? Again, not good during coding.

The positive connector is a spring. A wire is soldered to the end of the spring (where it makes contact with the outlet). At first I thought this to be an after-thought... Too much resistance in the long thin spring-wire? Why not just use a bigger gauge spring? Ohhhh... A looser spring is less likely to push itself outta the socket! Smart!

OK, how to connect with this thing? Maybe I can find a butt-crimp whose inner diameter is just slightly smaller than the spring and screw it on. Not quite. And crimping... well... I'd rather not damage that solder joint. (I think it's enamelled wire, crimping it may do no good!). Ahhh, insert into a big butt-crimp, and only crimp *after* the solder joint. Awesome. And the crimp deforms the spring and pinches it on the sides... no twist/pull-out. Great!

Found out the hard way, though, that my wire, even when folded three times, was too small. Now stuck with a crimp and nothing in it... Kinda looks a bit like a female spade terminal... Bam, male spade. Actually, male spades are too wide, so I used an eye-terminal, squished it to oblong, forced it in, then recrimped. Good-nough.

Finally the negative terminals... what the heck am I gonna do about them?! They're stamped sheetmetal with a large nub... Tried crushing that nub small enough for a butt-crimp, nogo. Finally just cut off the nub and was left with... duh... a spade.

(Did I mention I've gotten a bit carried away with the crimper? "When [all] you've got [is] a hammer, everything looks like a nail" I guess.)

So, all that wonkiness is... apparently... more reliable than some USB connectors and a car outlet.

But, I am pretty proud of the 'wire wrapping' technique I came up with... Am pretty sure that should be pretty durn reliable.

And the ol' devel system won't lose power when it's time for heat! And I finally got to watch the Garfield Halloween DVD. And I was able to recover my hard disk, photos, custom devel tools/environment, #commonCode, etc.