Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
OK, you generally don’t buy hoses “by the ounce”, but “per fluid ounce” may not mean what you think it means:
Amazon unit pricing – cups per ounce
Pricing items individually should be simple, if you know what a single item is:
Amazon unit pricing – batteries per each
Even knowing the number of items and the overall price isn’t enough for Amazon to get it right:
Amazon unit pricing – just plain wrong
Amazon now has a “shopping assistant”, so I asked Alexa why the unit prices were incorrect. After some back-and-forth providing details Alexa should have known from the context, this seemingly plausible sequence of words emerged:
Two years ago I installed the DuckDuckGo browser on my phone and activated its app tracker blocking, which is basically a fake VPN swatting known tracker destinations out of the bitstream.
Somewhat to my surprise, the credit union’s app attempted to send my personally identifiable bits to a destination seemingly unrelated to any banking needs:
HVCU App Tracking – 20240525
So I called up the credit union and asked:
Why was their app sending that information to a third party?
How do I disable that tracking, because I do not want those companies to know every time I use the app?
Why did they think this was a good idea?
Over the course of the next few weeks and many follow-up calls, I was told:
I must be mistaken, there is no tracking
My information is correct, but the credit union doesn’t have a relationship with that company
They do have a relationship, but the app doesn’t send any of my information to that company
They only send the information if I am responding to a survey
The app does send my information even without my responding to a survey, but in accord with their privacy policy
OK, the credit union’s privacy policy doesn’t specifically describe their app, but the companies behind the app have privacy policies at various links
Even though the documents at those links describe the general sharing arrangement between each company and the credit union, I am not authorized to see the specific agreements related to my information
I can opt out of the tracking by setting an option in my account profile
OK, that option doesn’t exist, but when I disable the app’s access to my location, the tracking will cease
The intensity of the tracking attempts continued, even after disabling location sharing and not opening the app on any given day:
The sign makes it fairly clear what NYS DOT intended, even if they don’t dogfood their designs:
Raymond Avenue vs pickup – bikes in lane sign
We ride to the left of the fog line for good reason:
Raymond Avenue vs pickup – drain grate
Those are nominally “bike safe” drain grates, but some of the joints between the catch box and the grate can snag a bike tire, so they’re best avoided. Bonus: not all the drain grates are bike safe, so making a mistake will be costly.
The lane has enough clearance for passing cars, presuming you don’t flinch at the wrong moment:
Raymond Avenue vs pickup – lane clearance
That same DOT engineer told me the correct way for cars to pass is to drive up on the sloped curb onto the median. Some drivers do that, but further down Raymond they would collide with various obstructions.
Not flinching is difficult to do when there’s a horn blaring immediately behind you:
Raymond Avenue vs pickup – overhanging load
I wonder if the mattress was on its way to the dump.
We’ve begun exiting at Chapel Gate and riding through campus:
Raymond Avenue vs pickup – Chapel Gate
Which is exactly what the DOT engineer who designed Raymond suggested we do. Why a state agency can recommend riding on private property to get off a nominally standards-compliant state road remains a puzzle, but, hey, I’m no longer a Registered Professional Engineer.
IMO, the man needs a bigger pickup:
Raymond Avenue vs pickup – not enough truck
Just another day riding on NYS DOT roads, where bicycling is always an uninterrupted delight.
While setting up a Raspberry Pi camera, I had occasion to pull out its USB power cable, whereupon grabbing the camera while unscrewing it from the tripod felt unusually sharp:
Micro-B USB – RPi jack
It seems the wall wart’s USB Micro-B connector pulled apart:
Micro-B USB connector – disembowled
Somewhat to my surprise, it was a CanaKit 5 V 2.5 A wall wart, definitely not the cheapest piece of junk ever made by the hand of man. On the other paw, it’s been around for quite a while, so …
Even I will agree that’s not a repairable failure, so I planned to splice in a Micro-B connector from a volunteer chosen from the Box o’ USB Micro-B Cables:
Each of those conductors appears to be made up of nine springy copper-colored 0.06 mm strands, somewhat smaller than 40 AWG: not what you want on the business end of a 2.5 A wall wart. I had previously measured the cable’s overall resistance with a surprisingly useful Treedix USB Cable Tester and it was on the very high end of the charge-only cable collection.
So I soldered a female USB-A breakout from the Drawer o’ USB Breakouts to the wall wart’s wires, snapped a 3D printed case around it, got a good (0.26 Ω) A-to-Micro-B cable from the Box o’ USB Adapters, and moved on.
Our ancient Branson 200 Ultrasonic Cleaner began behaving erratically due to water seeping under the rather casual seal from last year’s fix. Although drying the switches let it start up again, it would run for only a few seconds before shutting down again, which suggested a deeper problem than just the switches.
Take a picture of the PCB’s component side:
Branson 200 Ultrasonic Cleaner – PCB component side
And of the solder side:
Branson 200 Ultrasonic Cleaner – PCB solder side
Transform those pictures to be the nice real rectangles shown above, resize to a common pixel format, mirror the solder side, turn it into a layer atop the component side, then tweak its opacity to make both sides visible at once:
Branson 200 Ultrasonic Cleaner – PCB overlay
Some pondering produces a partial schematic of the left half of the board:
The 1:1 transformer is constantly powered, so the ON button connects the 120 V (!) half-wave rectified output to the +12V supply bus, with the 750 Ω resistor dropping most of the voltage while the switch is pressed.
The hotwired +12V supply forces the relay closed, which (in some as-yet unidentified way) fires up a +12V power source to hold the relay closed, with the 555 timer driving an MC14060 14-bit divider to count down the time until it turns itself off.
Reminder: this design dates back to the days when a pair of chips and a handful of through-hole components cost less than one of those fancy microcontroller thingies.
Plug the cleaner into an isolation transformer and trace the half-wave rectified signal through ON button to find it got all the way to the contact on the end of the orange wire in the connector, but did not reach the pin header on the PCB.
A closer look at the connector revealed a broken contact on the white wire, which I (rather crudely) soldered together while considering my choices:
Branson 200 Ultrasonic Cleaner – soldered contact
While plugging that wire back in place, this happened:
Branson 200 Ultrasonic Cleaner – another broken contact
Neither of those are the (presumably) similarly failed orange wire, but even I can get a clue from three similar failures.
So I replaced the OEM connector with a JST-XHP 2.54 mm connector from an assortment I got for another project, replaced the chunky 22 AWG wires with flexy 26 AWG silicone wires in the same cheerful rainbow colors, and it began working perfectly again.
The buttons needed another water seal, so I tweaked the previous layout to kiss-cut GITD tape and through-cut colorful vinyl sheets:
Branson 200 Ultrasonic Cleaner – power button cutting
Capped with a transparent cover sheet cut from a pack of PDA screen protectors (remember PDAs?):
Branson 200 Ultrasonic Cleaner – power button cover
In truth, the GITD tape is too thick, so I’ll probably repeat this dance later this year.
FWIW, I was totally ready to buy a new ultrasonic cleaner, but all of them have scathing one-star Amazon reviews, to the extent I decided fixing this cleaner would be much easier than fixing a new one that’s been cheapnified to the point of no return. A common complaint seems to be water leaking into their capacitive switches and killing the circuitry stone cold dead: not an improvement over this one.
Work Sharp Precision Sharpener – Blade Clamp operation
What’s not obvious is that the socket can rotate only 180°, which means you (well, I) must remember which way to turn it based on the presence or absence of the small white mark. I get it wrong somewhat more than half the time while sharpening a small symmetric blade, rather than a knife with a handle, so I added arrows to the socket.
With the white mark upward, turn 180° counterclockwise:
Under the plausible assumption the security / surveillance cameras along the Walkway Over the Hudson aren’t the cheapest junk available from a randomly named Amazon seller, this came as a surprise during a recent Walkway At Night stroll:
Walkway Over the Hudson – camera LEDs
The IR LEDs emit just enough red light to be dimly visible to the human eye, but appear much brighter to a silicon detector. I think the long gap at the bottom right is a sensor of some sort, so the array of 18 LEDs has two deaders, one near death, and six more fading away.
The Smell of Molten Projects in the Morning 