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.

Author: Ed

Baofeng UV-5RE: BL-5 Battery Overview

After I mentioned I was thinking of repurposing the nearly unused lithium-ion batteries from the Wouxun KG-UV3D radios for a blinky light, Dragorn of Kismet introduced me to his Baofeng UV-5 radio. The radio itself seems to be the worst amateur radio you’d be willing to use, but when seen as a standardized battery and drop-in charger with a free radio and antenna tossed into the deal, it’s not all that bad:

Baofeng UV-5RE radio – overview

The Wouxun and Baofeng 7.4 V batteries allegedly have similar capacities: 1700 vs 1800 mA·h. The Baofeng also has a 3800 (or 3600) mA·h pack that extends well below the base of the radio (not all large packs seem to be compatible with the UV-5RE radios I got); that would be roughly equivalent to the larger packs that power the Wouxun / APRS / voice gadgetry on the bike.

The Baofeng battery pack is smaller and has features that seem less likely to misbehave on a bike.

It has a latching tab with a ramp and a positive notch, with ridges around the edge that engage the radio shell:

Baofeng UV-5RE radio – battery latch tab

The radio body (which is what I must duplicate) has a movable latch tab above the battery contact pins, so the latch holds the battery into the compartment. The spring-loaded pin pairs are wired in parallel, presumably for redundant contact with each battery terminal:

Baofeng UV-5RE radio – battery compartment latch and contacts

The battery terminal pads are reasonably well protected by the tab:

Baofeng UV-5RE radio – battery contact pads

The battery slides into the radio compartment and latches with a snap. Two holes on the battery base engage a pair of pegs on the radio case:

Baofeng UV-5RE radio – battery base detail

The holes are rounded rectangles and the pegs have one corner sliced off. The pegs seem entirely too fragile and not well suited for 3D printing, so some metalwork may be in order. The pegs must resist only pulling forces perpendicular to the case back, not sliding forces, and the case constrains side-to-side motion.

The two square posts (with two others not shown) form the “feet” that support the radio when it’s standing on the desk or in the charger.

Now, to doodle up the dimensions and measure the actual capacity.

Speaking of capacity, BL-5 batteries on eBay range from $23 for “genuine Baofeng” that may or may not actually have that name on the label, all the way down to $8 for the usual no-name equivalent.

2013-09-04
Cheap Boost Power Supply Evaluation

For reasons that will become apparent in a while, I got a pair (*) of boost power supplies from the usual eBay source, allegedly capable of boosting a 10-to-32 VDC input to a 12-to-35 VDC output, up to 10 A and 150 W:

Boost power supply

After establishing that it would not produce 30 V into a 5.9 Ω load (5.1 A, but 152 W), I got systematic.

A 100 Ω resistor drew 1/4 A while I set the output to 28 V. Doubling up the resistors showed that it worked OK at half an amp:

Boost supply – 50 ohm load

Four 6 Ω resistors in series draw 1.2 A, then (channeling the true spirit of DIY 3D printing) two in series drew 2.3 A:

Boost supply – 12 ohm load

That’s 32 W each and, yes, they did get toasty, but, no, I didn’t leave them turned on all that long.

But a 6 Ω resistance still didn’t work, so the supply can’t provide 4.7 A at 130 W. In case you were wondering, that’s two 6 Ω resistors in series and a pair of those strings in parallel, so each resistor still sees 32 W.

In terms of driving the actual load, these supplies aren’t going to light it up.

Ah, well, whaddaya want for five buck from halfway around the planet?

(*) Davy’s Aphorism: Never buy only one of any surplus item, because you’ll never find another. Get at least two, maybe three if it’s something you might actually use.

2013-09-03
Gift From a Spammer: Captcha Cracking Data

Although I’d prefer open commenting, that just isn’t practical: spambots manage to create WordPress.com user accounts and post about 300 spams per day, of which I see perhaps a dozen false positives. Asking you to either sign in or provide some details helps slow the torrent.

Another inept spammer recently posted Yet Another un-expanded comment template, but the bungled script added some interesting information to the bottom. Here’s the last few lines from several pages of raw comment gibberish, with the URLs snipped out to protect the innocent:

{number|quantity|amount|range|variety|selection|multitude|wide variety|phone number|figure|telephone number} {=|Equals|Equates to|Is equal to|Means|Implies} {price|cost|value|price tag|selling price|amount|expense|rate|total price|charge|fee} {return|come back|go back|give back|returning|gain|profit|yield|revisit|bring back|keep coming back}).

[Generic URL snippage] Result: chosen nickname “ronalngh”; captcha recognized; success;
[Asian URL snippage] Result: chosen nickname “ronalvzo”; captcha decoded (4 attempts); success – posted to first encountered partition “理桁桊钼囗睇?钺铊”;
[Russian URL snippage] Result: SERVER ERROR (host dpk-svetlana.ru); chosen nickname “tomsckt”; registered (100%); logged in; success (profile was registered successfully, but there is no permissions for creating new topic);

Thus confirming that even captchas don’t pose much of a challenge these days…

2013-09-02
Monthly Science: Basement Safe Silica Gel Equilibria
A month ago I tossed a new bag of silica gel into the basement safe and put the used one on the workbench to see how much more water it would adsorb. The numbers worked out like this:
- Bag + staples: about 8 g
- Dry weight: 500 g of silica gel beads
- At 24%RH: 575 g = +67 g water
- At basement ambient, about 50%RH: 652 g = +144 g water
- At upstairs ambient, about 65%RH: 673 g = +165 g water
Referring to the Sorbent Systems charts…

At 50%RH, the capacity is about 27% = 135 g of water, which is close to the measured 144 g. The logger recording groundwater temperature says the average humidity hovers just under 55%RH, in which case 28% capacity = 140 g of water: as close as you could possibly hope for.

At 65%RH, the capacity is about 32% = 160 g of water, which is very close to the measured 165 g.

The safe humidity remains flatlined at the logger’s 15%RH minimum level, with one blip when I installed the door gasket strips:

Basement_Safe – 2013-08-28

After I accumulate a few more used bags, we’ll see how well they regenerate.
2013-09-01
Survey Registration Number: Faceplant

A giant envelope containing one of those “political surveys” that’s actually a thinly disguised fundraiser arrived, with this confidence-inspiring ID in the upper-right corner:

Survey Registration Number

The questions were all examples of false dichotomies.

A pox on their backsides, sez I.

2013-08-31
Why I Won’t Fix Your Windows PC

Got a call from a friend who was having trouble getting BitDefender to accept its new license key, so I drove over; she’s at the top of a killer hill and I’d already biked my two dozen miles for the day. Solving that problem was straightforward, if you happen to know that they use “authorization” and “license” as synonyms and that you access the key entry dialog by clicking on a text field that doesn’t look at all clickable.

I should have declared victory and returned to the Basement Laboratory, but, no, I had to be a nice guy.

BitDefender kvetched that it had been 777 days since its last scan, so I set up some regularly scheduled scans and automagic updates for everything in sight; we agreed she’d just let the thing run overnight on Mondays to get all that done.

BitDefender also suggested a handful of critical Windows XP updates, plus the usual Adobe Flash and Reader updates, plus some nonsense about Windows Live Messenger that seemed to require downloading and installing a metric shitload of Microsoft Bloatware. Rather than leave all that for next Monday’s unattended update, I unleashed the critical ones, did the Flash and Reader updates, and stuffed the Messenger update back under the rug.

Then AOL recommended an urgent update to AOL Desktop 9.7. She has a couple of AOL email addresses, mostly for historic reasons, and I asked if she ever used the AOL Desktop. She wasn’t sure, so I lit up the installed AOL Desktop 9.6: “Oh, that’s how I get all my email!” OK, so we’ll update that, too.

After all the thrashing was done, the system rebooted and presented us with the single most unhelpful error message I’ve ever seen:

Windows Error – Ordinal Not Found

No, you chowderheads, that is not OK…

Searching on the obvious terms indicated this had something to do with Internet Explorer 8 (remember IE 8?) and produced a number of irrelevant suggestions. The least awful seemed to involve running the Microsoft System File Checker utility:

sfc /scannow

Which I did.

It ran for the better part of an hour, then suggested a reboot. During the shutdown, it replaced 29 files at an average of about 5 minutes per file.

After which, Windows restarted and displayed exactly the same error message. Actually, a series of them; various programs couldn’t locate a fairly wide selection of ordinals in several DLLs.

OK. I give up.

We located a tech who does this sort of thing for a living. I’ve offered to split the cost of getting the box up and running again, with the understanding that it may be easier to start with a fresh off-lease Dell box running Windows 7 than to exhume an aging Windows XP installation.

I stopped caring about Windows toward the end of the last millennium and now keep a Token Windows Box only for hardware like the HOBOWare dataloggers and software like TurboTax.

Other than that, well…

I. Don’t. Care.

2013-08-30
Tour Easy: Another Kickstand Plate

I managed to lose another kickstand plate, sooo…

Kickstand plate

The horrible paint crazing came from “priming” the bare plywood scrap (yes, that’s a stray hole from its previous life) with a specialty white paint intended for plastic lawn furniture; it apparently gets along poorly with the forget-me-not fluorescent red topcoat. Doesn’t matter in this application and uses up more of both rattlecans, so it’s all good.

Of course, after tucking it in the bike’s underseat bag, I spotted the lost plate along the DCRT: now I have a spare!

2013-08-29