Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Category: Science
If you measure something often enough, it becomes science
The second batch from the same eBay source arrived a few months later and I finally got around to measuring them:
60 kHz TF26 resonators – Batch 2 data
A dot of green Sharpie on the AT26 cans identifies the second batch:
60 kHz TF26 resonators – Batch 2 marking
The alert reader will notice an un-measured 25th resonator at the bottom of the first batch. I dropped one from the second batch under the Electronics Workbench, found it, then also found its long-missing brother; now I have a genuine it’s-never-been-used resonator, just in case the need arises.
A quick-and-dirty simulation shows the series and parallel resonant peaks come out close, but not dead on, the actual measurements:
Simulation – 60 kHz resonator
The model obviously doesn’t exactly match reality, which isn’t too surprising. However, I don’t understand something about tuning fork resonators, because the parallel resonance shouldn’t shift upward with the series resonant peak when the circuit gains a 24 pF series capacitance:
Resonator 0 Spectrum
Suffice it to say that doesn’t happen with the simulation.
The replacement NP-BX1 batteries arrived and, as I expected, perform just as badly as the previous pair:
Sony NP-BX1 – Wasabi GHIJK – 2017-09-01 – annotated
The note I sent to Wasabi’s tech support summarizes the details:
The second pair of NP-BX1 batteries are just as bad as the first two. In fact, all four perform worse than the nearly two-year-old Wasabi batteries I’ve been using.
The graph shows the test results from my CBA III analyzer. All batteries were all charged in a Wasabi wall charger.
The top solid red curve shows the as-delivered performance in late 2015 for the battery I labeled “G”, tested at 500 mA. It delivered only 1 Ah, not the claimed 1.6 Ah, even at that relatively low current, but has delivered over one hour of service in the camera.
The top dotted-blue curve shows the as-delivered performance for the NEW battery I labeled “J”, also tested at 500 mA. It delivers only 0.88 Ah, 55% of the claimed 1.6 Ah, at a much lower voltage while discharging.
After two years, OLD battery “G” has more capacity and a higher voltage than the NEW battery “J”!
The lower curves shows the results for the four most recent batteries I labeled H I J K, all tested at 1 A to better match the camera’s actual current; the dotted traces mark the second test of each battery.
The orange traces show battery K has about 0.77 Ah of capacity, less than half of the claimed 1.6 Ah and much worse than the others.
I also re-tested battery old battery G at 1 A, as shown by the dotted red curve labeled “G:2017-09”. It outperforms ALL of the new batteries!
Batteries H and I have date codes BQF22, which I interpret as 2017-06-22: fairly recent stock.
Batteries J and K have date codes BPL28: 2016-12-28. They’ve been sitting around for a while, which may account for the poor performance of battery K.
These Wasabi batteries cost roughly twice (*) as much as they did in late 2015, have /much/ lower capacity, and, to judge from the date codes, they’ve been consistently poor since late last year.
What is going on?
It’s worth noting that Wasabi NP-BX1 batteries are currently $16 for the pair on Amazon and were $9 in late 2015. Allegedly genuine Sony NP-BX1 batteries run $50 MSRP and a suspiciously consistent $37.99 from all the usual big-box sources, including Amazon, where they’re out-of-stock for the next few months. Combining the number of counterfeits in the supply chain with Amazon’s commingled SKU stock bins, I have my doubts about what I’d get by increasing my battery spend by a factor of five.
I think it’s about time to conjure an external 18650 holder / helmet mount for that camera and be done with it.
[(*) Edit: I screwed up the unit of measure: the old invoice had two single batteries. The new order was one pair, so I now pay slightly less for much worse performance. A refund is wending its way through the system.]
An hour before the festivities started, I lashed together an official NASA-approved pinhole eclipse viewer from available materials:
Eclipse 2017-08-21 – pinhole projector
Although the solar disk showed up fine on the white paper screen, the Pixel’s camera can’t show the notch growing on the left side, even with HDR+ mode in full effect:
Eclipse 2017-08-21 – pinhole projector – interior
As usual for astronomy around here, clouds threatened the outcome:
Eclipse 2017-08-21 – high clouds
Near the maximum, the skies cleared:
Eclipse 2017-08-21 – maximum – lens flare
Although it’s not proof, there’s a definite bite out of the lens flare at about 4 o’clock:
Eclipse 2017-08-21 – maximum – lens flare – detail
The maples south of the driveway produced lower-contrast images better suited to silicon sensors:
Eclipse 2017-08-21 – maximum – shadows
And, although everyone was specifically enjoined not to do this, because UV reflection = blindness, the obligatory solar eclipse selfie:
Eclipse 2017-08-21 – obligatory selfie
I’m sure similar lens flares count as UFOs in someone’s telling of the tale.
We planned to dance naked in the yard, but our neighbor’s lawn crew picked that moment to scalp his grass and we chose discretion over valor …
(Typo in the permalink: should be W vs. X. Fixing it will break all the auto-linkies. Hate it when that happens.)
When our lass first began using calculators, I put a pair of Sharp EL-531W calculators in harm’s way around the shop, where they still reside. The new EL-531X seems to have an identical key layout and internal logic (*), as well as the same under-ten-buck price, but I don’t like it nearly as much:
Sharp EL-531W EL-531X calculators
It’s maybe 10 mm wider and doesn’t fit readily in my hand. I’m sure the rounded-rectangle stylin’ mimics a phone, but the cheapnified keys look ugly(particularly the ones around the arrow keys at the top) and don’t feel nearly as good.
The new one fills a gap next to the lathe, where it should collect plenty of swarf.
(*) Including engineering notation with multiple-of-three exponents, which I regard as vital.
Each of the three Mystery Caterpillars wandered around the aquarium for a few minutes, found a spot surrounded by leaves, and tucked themselves into their cocoons.
The smallest one went first and probably got the best site:
Mystery Caterpillar – Cocoon 1
The medium one:
Mystery Caterpillar – Cocoon 2
The largest caterpillar munched the leaf around the new cocoon and removed some of the silk (?) wrapper. It looks like the caterpillar’s fur falls off and becomes insulation inside the wrapper.
The large one with mostly black fur managed to bind two leaves together:
Mystery Caterpillar – Cocoon 3
The Monarch remained calm, well above the scramble:
Monarch Chrysalis – with skin
The caterpillar’s skin (or whatever it is) remained loosely attached to the outside.
The Sandisk Extreme Pro 64 GB MicroSD card in the Sony HDR-AS30V died on the road once more, got reformatted, worked OK for a while, then kicked out catastrophic I/O errors after being mounted, so I swapped in the High Endurance card:
Sandisk – 64 GB MicroSDXC cards
The Extreme Pro still passes the f3probe tests, so it’s not completely dead, but if I can’t trust it in the helmet camera, it’s dead to me.
It survived 17 months of more-or-less continuous use, although we didn’t do nearly enough riding for three months early this year. Call it 14 months x five rides / week x 1 hour / ride = 300 hours of recording. Multiply by 4 GB / 22.75 minutes to get 3 TB of video, about 50 times its total capacity.
The never-sufficiently-to-be-damned Sony cards failed after less than 1 TB and 15-ish times capacity, making the Sandisk Extreme Pro much better. However, it’s painfully obvious these cards work better for low-intensity still-image recording, rather than continuous HD video.
Using them as Raspberry Pi“hard drives” surely falls somewhere between still cameras and video, although Octoprint’s video snapshots and streaming media must make ’em sweat.
We’ll see how Sandisk’s High Endurance memory works in precisely the application it’s labeled for.
The Smell of Molten Projects in the Morning 