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.

Category: Electronics Workbench

Electrical & Electronic gadgets

Sandisk Extreme Pro MicroSD Card: End of Life?

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.

2017-08-22
Tenergy 18650 Lithium Cells: Initial Capacity

The daytime running lights on the bikes get noticeably dimmer when the 18650 lithium cell voltage drops below 3.6 V, so I picked up a quartet of Tenergy protected cells and ran ’em through the battery tester:

Tenergy 18650 Protected – 2017-08-04

As with the ATX cells, the voltage decreases almost linearly with charge until it falls off the cliff near the end, but these have a higher terminal voltage throughout most of the curve, which is a Good Thing for LED flashlights.

These four seem to have about the same overall capacity as the ATX cells, so we’ll run ’em all in sequence and see how long they last.

2017-08-21
Wasabi NP-BX1 Batteries: FAIL

I just got a new pair of Wasabi Power NP-BX1 batteries for the HDR-AS30V helmet camera, charged them up, and ran them through the CBA:

Sony NP-BX1 – Wasabi FGHI – 2017-08-08

Huh.

The new ones (H and I) cost near twice as much as the 2-1/2 year old previous pair (F and G), while delivering less energy at a lower terminal voltage. Tested ’em twice to be sure and the curves overlay just about perfectly, so it’s not a fluke.

The rep assures me the replacement cells will deliver their promised capacity. We shall see.

2017-08-16
J5 V2 Flashlight: Switch Tightening

From the start, the (second) J5 V2 flashlight had an erratic switch that flickered the LED at the slightest pressure. Not enough to switch modes, as it does with a half press, but enough to show something’s not quite right inside.

Taking it apart requires a pin wrench, which I have, but the deeply recessed ring required more reach than any of the tips I’ve made over the years. Introducing a pair of stainless steel 10-32 screws to Mr Grinder added two more pins to the collection:

J5V2 Flashlight – custom pin wrench

The lock ring in the flashlight cap turned out to be finger-loose, certainly contributing to the problem. Removing the lock ring, peeling the rubber dome out of the cap, and poking with a punch sufficed to drive out the guts of the switch assembly:

J5V2 Flashlight – switch parts

Which consists of, as you’d expect, the cheapest possible parts that don’t immediately fail.

The (steel) tab sticking out of the actual switch (in the upper right) contacts the inside of the (aluminum) cap. I bent it slightly outward, added a trace of DeoxIT Red, reassembled everything in reverse order, and it’s all good for the first time in its brief life.

I’d rate J5’s QC as Below Average, given that the first light arrived with built-in dirt and its replacement (this one) had an alien egg next to the LED, plus this loose switch lock ring + crappy tab contact.

The J5 V2 light claims 750 lumen output, but the spot is nowhere near twice as bright as the LC40 lights on the bikes and much dimmer than the LC90 light (which is too big for the bikes), all tweaked for equivalent-size illuminated areas. Given that lumens measure total output and candela measure lumen/steradian, there’s some wiggle room for misinterpretation.

Won’t buy another, for sure.

2017-08-14
Canon NB-5L Battery Status

My pocket camera has begun kvetching about a low battery rather more often than before, which suggests the batteries I’ve been using since 2014 have gone beyond their best-used-by date.

This came as no surprise:

Canon NB-5L – 2017-08-05

I re-ran a couple of the batteries to make sure they hadn’t faded away from disuse, which didn’t materially change the results. The lightly used Canon OEM battery continues to lead the, ah, pack.

The camera’s lens capsule accumulated a fair bit of dust from many years in my pocket, which lowers its overall contrast and wrecks the high f/ images produced with the microscope adapter.

2017-08-10
Quartz Resonator Test Fixture: Cleanup
Isolating the USB port from the laptop eliminated a nasty ground loop, turning off the OLED while making measurements stifled a huge noise source, and averaging a few ADC readings produced this pleasing plot:

Resonator 0 Spectrum

Those nice smooth curves suggest the tester isn’t just measuring random junk.

The OLED summarizes the results after the test sequence:

LF Crystal Tester – OLED test summary – Resonator 0

Collecting all the numbers for that resonator in one place:
- C0 = 1.0 pF
- Rm = 9.0 kΩ
- fs = 59996.10 Hz
- fc = 59997.79 Hz
- fc – fs = 1.69 Hz
- Cx = 24 pF
Turning the crank:

CC 2017-11 – Resonator 0 Calculations

I ripped that nice layout directly from my November Circuit Cellar column, because I’m absolutely not even going to try to recreate those equations here.

Another two dozen resonators to go …
2017-08-08
Amazon Packaging: Lithium Ion Cells

The mandatory warning stickers leave no doubt as to what’s in the box:

Amazon – Lithium Ion Battery Warning Stickers

You can imagine my relief when the lithium cells arrived intact:

Amazon – Lithium Ion Battery – packaging

FWIW, the ATK lithium cells arrived in a small box, snugly tucked into a form-fitting foam block:

ATK Lithium Ion Cell – padded box

As long as nothing happens, it doesn’t matter, right?

You’d think Amazon would have learned something from their day in court, though …

2017-08-07