Archive for category Oddities
Dutchess Rail Trail: Maloney Rd Trailhead Ruts
Posted by Ed in Oddities, Recumbent Bicycling on 2018-12-10
It seems the DCW&WA SUV makes regular trips through the “No Motor Vehicles” bike access:
Maloney Rd Trailhead – 2018-11-07
If it’s not them, then it’s somebody following their example.
Just because you can do something, doesn’t mean you should … but, of course, the ordinary rules apply only to little people, not public servants.
Someone in the bike advocacy apparat once told me I’m the most cynical, bitter person they’d ever met, at least on the subject of getting along with public servants. As I see it, I came by my attitude honestly.
Three Dead Mice
The rodents around here have great trouble with outdoor bowls, but this trio ended in a deep six gallon bucket next to the garage workbench:
Three Dead Mice
Even though mice don’t seem like cuddly creatures, they ended their days snuggled together; we’ll just ignore the cannibalism thing.
Heck of a way to go, even for rodents. I renewed the steel wool blocking a gap in the garage door.
Ants in My Drawers
Our Compact Edition of the OED doesn’t get much use these days, but Mary needed a magnifier for a class on quilt judging and the OED has one that seemed just about right:
OED Magnifier Box in drawer
The magnifier comes in a removable box fitted neatly into the drawer, revealing a surprise underneath:
OED Magnifier drawer – plastic ant
A detail view:
OED Magnifier drawer – plastic ant – detail
It’s a plastic ant from a bag in the Kiddie Surplus box my Shop Assistant grew up with and a pleasant reminder of long-ago days, carefully placed where only I’d ever see it.
Of course, it’s still there …
Monthly Science: Motel Water Pressure vs. Height
Being a sucker for infrastructure and numbers, the fire sprinkler system pressure gauges in the motel stairwell proved irresistible.
The first floor gauge shows a nice round 100 psi:
Hotel water pressure – floor 1
Up on the second floor, it’s 90 psi:
Hotel water pressure – floor 2
With a different brand of gauge, it’s also 90 psi on the third floor:
Hotel water pressure – floor 3
Maybe 85 psi on the fourth:
Hotel water pressure – floor 4
Squinting at the parallax, call it 80 psi on the fifth:
Hotel water pressure – floor 5
At the top of the vertical pipe on the fifth, on the other side of a valve, we return to the original valve company at 78 psi:
Hotel water pressure – floor 5 – top
Water weighs just over 62 lb/ft³ at room temperature, which works out to 0.43 lb/in² per vertical foot. Not having packed my laser distance widget, I’ll guesstimate 12 feet and 5 psi per floor.
A quick graph with an eyeballometric straight-line fit:
Motel sprinkler water pressures
Call it 0.42 psi/ft, which is pretty close to the right answer.
Astable Multivibrator vs. Charged NP-BX1 Lithium Battery
Posted by Ed in Electronics Workbench, Oddities, Science on 2018-11-30
Hitching a charged, albeit worn, NP-BX1 lithium battery to the astable multivibrator produces a blinding flash:
NP-BX1 Holder – SMT pogo pins
The current pulse shows the wearable LED really takes a beating:
Astable – NP-BX1 4V – 100mA-div
The current trace is at 100 mA/div: the pulse starts at 400 mA, which seems excessive even to me, and tapers down to 200 mA. It’s still an order of magnitude too high at the end of the pulse.
On the other paw, maybe a 14% duty cycle helps:
Astable – NP-BX1 4V – base V – 100mA-div
The top trace shows the base drive voltage dropping slightly, although I suspect the poor little transistor can’t take the strain.
The LED really does need a ballast resistor …
Monthly Image: AMP Plug Board
Posted by Ed in Electronics Workbench, Oddities, Science, Software on 2018-11-15
Around 1960, somebody my father knew at the Harrisburg AMP factory gave me a chunk of plugboard bandsawed from a scrapped computer or industrial controller, because he knew I’d enjoy it:
AMP Plug Board
He was right.
I spent months rearranging those little cubes (some with cryptic legends!) into meaningful (to me) patterns, plugging cables between vital spots, and imagining how the whole thing worked:
AMP Plug Board – detail
Long springs ran through the notches under the top of the blocks to connect the plug shells to circuit ground. The ends of the steel rails (still!) have raw bandsaw cuts, some of the blocks were sliced in two, the tip contact array behind the panel wasn’t included, and none of that mattered in the least.
Only a fraction of the original treasure trove survives. It was absolutely my favorite “toy” ever.
Quite some years ago, our Larval Engineer assembled the pattern you see; the hardware still had some attraction.
I’ve asked Mary to toss it in the hole with whatever’s left of me, when that day arrives …
Power Over Audio
Posted by Ed in Electronics Workbench, Oddities on 2018-11-04
An obsolete Intuit / Roam Data credit card reader emerged from the heap:
Intuit Roam Data Reader
“Turn up the volume” suggestes where the power comes from:
Intuit Roam Data Reader – plug wiring
They drive a LOUD, probably square-ish, audio signal through both “earphone”channels, rectify and regulate the output, and have plenty of power for the reader. The card data returns through the “mic” as another audio signal; I assume they choose an encoding well-suited for a dab of DSP decoding.
Nowadays, of course, 3.5 mm jacks are obsolete, audio data travels by Bluetooth, and you must keep a myriad of batteries charged at all times.
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