Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
A Round Tuit™ finally arrived for this long-delayed project:
Vise soft jaws – installed
They’re bandsawed from an impossibly heavy-duty U-shaped aluminum extrusion salvaged from a scrap pile; the flanges are 6 and 7 mm thick. I’ll put in a good word for the Proxxon 10/14 TPI blade, because it goes through aluminum plate like butter.
The wood strip under the top flange raises the fillet on the interior angle enough to let the extrusion sit flat on the top vise jaw and square against the gripping side. It’s held in place with double-sided carpet tape.
They’re faced with a rubber sheet I thought was twice as thick when I picked it out of the Big Box o’ Squishy Sheets, but turned out to be two thinner sheets invisibly stuck together. Carpet tape holds one of the sheets to the jaw; I expect the other sheet to fall off in short order.
You’re supposed to embed neodymium magnets in the jaws to hold them to the vise. As far as I can tell, they’re perfectly happy to just sit there all by themselves and, anyway, magnets would grow lethally sharp and bulky steel fur coats in short order.
Squaring the long edge didn’t pose much of a problem:
Vise soft jaws – squaring edge
Tidying the ends, however, required more setup:
Vise soft jaws – squaring ends
That’s the Sherline Tilting Angle Plate at 90°, with barely enough room on the far side for the base of a Starrett Double Square to set the extrusion vertical; the hand clamp holds it in place while tightening the step clamps. It sits on an aluminum sheet to put its upper end three smidgens over the angle plate, letting me flycut one smidgen for a clean edge.
Now I can retire the old soft jaws, which have served for too many decades and are far too ugly to show; improvised from weatherstripping glued to bent-square copper pipe and intended as a quick fix. You know how that goes …
Just for completeness, here’s what the various soaker hose clamps look like in the garden, as solid models only let you visualize the ideal situation:
Soaker Hose Connector Clamp – Show view
This one prevents a puddle in the path to the right:
Soaker hose repairs in situ – clamp
Bending the hoses around the end of a bed puts them on edge, with this clamp suppressing a shin-soaking spray to the left:
Soaker hose repairs in situ – end-on clamp
The clamp at the connector closes a leak around the crimped brass fitting, with the other two preventing gouges from direct sprays into the path along the bottom of the picture:
Soaker hose repairs in situ – clamps and connector fix
All in all, a definite UI improvement!
As far as I can tell, we have the only soaker hose repairs & spritz stoppers in existence. Hooray for 3D printing!
Back in the day, John Forester’s Effective Cycling defined how vehicular bicycling should be done; our now-fragile comb-bound 1980 Third Printing of the 1978 Third Edition still has a place of honor on our bookshelves. I recently discovered his analysis of how traffic signal timing should work online, which says I’ve drawn the wrong conclusions from my observations of the absurdly short green / yellow / red cycle on Burnett Blvd at Rt 55, just in front of NYS DOT’s Region 8 headquarters.
The phasing sequence that is required by current traffic law is as follows:
1. Green, which may be very short when only one vehicle is waiting
2. Yellow, of only sufficient duration to allow a stop from maximum legal speed before entering the intersection
3. Red (a 4-way red), for sufficient additional time for traffic to clear the intersection before the conflicting green appears.
With that in mind, here’s how his analysis stacks up against one of our recent trips through the intersection. The four-digit number in the picture titles gives the time in frames at 60 frame/sec.
We’re stopped one car length behind a long trailer of paving equipment sporting an Iowa license plate. The driver has stopped with the trailer straddling the lane divider line, so we cannot determine which way he will turn. Because we no longer trust turn signals, despite the trailer’s blinking left signal, we will not pull up beside it in the right lane.
Frame 0127, T = 0 s, Δt = 0 s: The signal has just turned green:
Burnett Opposing Green – AS30V – 2020-06-26 – 0127
Frame 0264, T = 2.28 s, Δt = 2.28 s: The trailer has started moving and Mary is rolling behind it, with her foot just coming off the ground:
Burnett Opposing Green – AS30V – 2020-06-26 – 0264
Frame 0721, T = 9.9 s, Δt = 7.6 s: The signal turns yellow, after DOT’s additional five seconds of green; previously, we had five seconds and would have been able to stop. We’re accelerating as hard as we can, but Mary has barely passed the stop line:
Burnett Opposing Green – AS30V – 2020-06-26 – 0721
Of course, entering an intersection on a stale yellow is undoubtedly unwise. It is not so unwise for someone traveling fast, because that person may well clear the intersection before the conflicting traffic starts. It is much more unwise for someone traveling slowly, but it is done and it is lawful.
Forester, ibid.
We’ve traveled about three car lengths in the seven seconds since the trailer started moving. Our bikes will sometimes trigger the signal if we’ve stopped in exactly the right spot over the unmarked sensor loops, but we have never observed our bikes retriggering the signal to lengthen the green or yellow phases as we ride through the intersection.
NYS DOT apparently expects us to stop abruptly when the signal goes yellow, wherever we may be with respect to the stop line and regardless of how fast we may be moving. In fact, given what you’re about to see, we’re expected stop on green to ensure we can start from the stop line during the next green signal.
Frame 0983, T = 14.2 s, Δt = 4.4 s: The signal turns red. The trailer is visible on the left, beyond the median signage, but we haven’t reached the middle of the intersection. I’m lined up with the rightmost lane of westbound Rt 55 and Mary is about in the center lane. The white car on our right is stopped, the black car is slowing to a stop:
Burnett Opposing Green – AS30V – 2020-06-26 – 0983
Frame 1101, T = 16.2 s, Δt = 2.0 s: The opposing signal goes green for Rt 55 traffic, while we’ve barely reached the middle of the intersection:
Burnett Opposing Green – AS30V – 2020-06-26 – 1101
Frame 1205, T = 18.0 s, Δt = 1.8 s: I’m lined up with the median, Mary’s in the center lane of eastbound Rt 55, putting us squarely in front of drivers who may be unable to see us through the stopped cars. The drivers to our left are, fortunately, waiting, unlike a previous crossing:
Burnett Opposing Green – AS30V – 2020-06-26 – 1205
Frame 1440, T = 21.9 s, Δt = 5.7 s: After 22 seconds, we’ve cleared the intersection and are proceeding eastbound on Rt 55:
Burnett Opposing Green – AS30V – 2020-06-26 – 1440
Forester observes the all-red phase must be lengthened to allow cyclists to clear the intersection. Right now, two seconds isn’t enough. Ten seconds would suffice for a pair of reasonably fit, albeit aging, cyclists.
This system fails to provide the required safety in the case of bicycles for three opposite reasons.
1. Bicycles are small and are harder to see. In particular, the most visually impressive part of the bicycle and rider is low down where it is easily shielded from view by the hoods of motor vehicles. Sometimes the only part of the cyclist that can be seen by drivers waiting at the stop line with other vehicles on their left is the head of the cyclist.
2. The cyclist crossing a typical intersection is close to the fronts of the line of cars waiting at the stop line on the cyclist’s right. This is not good judgement on the part of the cyclist, but so much emphasis has been put on staying far right that this position is typical.
3. The cyclist who is traveling slowly, or, more importantly, is starting from a minimum-duration green, is barely into a wide intersection when the conflicting green appears.
The result is a car-bike collision as one of the vehicles in the lanes nearest the curb starts up, or speeds up, and hits the cyclist who suddenly appears in front of it.
Forester, ibid.
I’ve had a DOT engineer tell me, sneeringly, that they don’t design facilities for “professional cyclists”, which commuting to work evidently made me; he was not, however, a “professional driver” even though he used a car for a similar purpose. It’s obvious DOT doesn’t design facilities for “ordinary” cyclists, either, and the evidence suggests they don’t design facilities for cyclists, period, full stop.
I still want someone from NYS DOT to explain how this “makes our highway systems safe and functional for all users“, perhaps by bicycling with us through the intersection a few times, but I’ve never gotten a response, let alone an answer, to anything I’ve ever sent their way.
The voltage (yellow) and current (green, 100 mA/div) waveforms look downright tame compared to some of the other chargers!
I made a cursory attempt to crack the case open, but gave up before doing any permanent damage. Hey, that UL listing (and, presumably, the interior details) means they’re three times the price of those Anonymous chargers!
In round numbers, a nasty COVID-19 infection ramps up for a week before you develop enough symptoms to finally get tested. Various states report various combinations of test results as confirmed / probable / tested “cases”, with “tested” including any possible combination (or lack thereof) of viral / antibody presence. As a result, the number of “daily cases” doesn’t mean much, but it’s the only number we’re likely to get. With that in mind, about 6% of those tested have a positive result for whatever they’re being tested for. Got that?
At some point within a week or two of being infected, tested, and found positive, about 2.8% of all cases will be hospitalized. That’s 2.4% of cases in the 18-49 age bracket and 4.3% of my decade (64-75):
Roughly a week (more or less, kinda-sorta) after hospitalization, 15% of all patients and 28% of those over 65 will die:
COVID-19 – Weekly Hospitalization Outcomes by Age – 2020-06-24
You get that chart from the Lab-Confirmed Hospitalizations page by dinking around with the controls for the lower-right pane. The Overall column represent 5800 patients and, as it happens, each column represents about 2000 patients.
Because it takes about three weeks to go from “infected” to “dead”, the ratio of [daily deaths today] to [daily positive test results from three weeks earlier] gives (In My Opinion) a better indication of the expected outcome than the simpler ratio of [today’s deaths] to [today’s test positives]. Because the news headlines always feature cumulative numbers, these numbers aren’t at the tip of anyone’s awareness.
The strong weekly component is surely a combination of data aggregation (no weekend reports?) and actual death events (nobody dies on Sunday?), but there’s no way to know from here. There’s plenty of noise in April which I decided to completely ignore; consult the raw data and draw your own conclusion.
Eyeballometrically, the lagged CFR has been declining linearly by 1% every 3 weeks since mid-May and should be around 2% in July. If you’re under 50 and in reasonable health, the news is even better, because you’re very unlikely to either need hospitalization or die from it. Again, work the numbers out for yourself from the raw data.
However, AFAICT, those results depend on a relatively unloaded healthcare system, because little of the US has (yet) to experience the catastrophic overload seen during the early onset in Washington state and NYC. This chart of ICU occupancy suggests the worst is yet to come for folks in states where expectations don’t match up to the reality of exponential growth:
COVID-19 – All-patient ICU occupancy – 2020-06-23
It seems having the ICUs tick along at 50% occupancy is about right, so the states with 70+% occupancy don’t have much surge margin.
Right now, COVID-19 is burning through the US population at about 30,000 confirmed new cases per day, which means 840 people will require hospitalization every day next week (in addition to all the usual hospitalizations for other causes) and, in another week, 126 people will die every day. Maybe 40 people under age 50 will die, so the human herd will develop immunity by killing off we Olde Fartes.
After I ran those numbers, the rate passed 40,000 cases per day, with no sign of slowing down and indications it’s getting worse faster. Scale my numbers up by 30%: 1100 hospitalizations and 170 deaths per day in a few weeks.
However, if you live in one of those dark purple states already showing 70+% ICU utilization, don’t do anything starting with “Hold my beer. Watch this!” because you will not get a welcoming Emergency Room reception. The CNN synoptic view of new cases continues to be informative.
One of Mary’s cronies is married to a guy who knows this whole COVID-19 thing is a hoax: “They’d all have died of something else, anyway.” Plotting all-cause fatalities vs. age (2020 in red, last five years in gray) shows tens of thousands of people are dying from something new this year:
All-cause deaths by age – current vs historical – 2020-06-26
Before you do the happy dance about the downward slope toward the right, read the disclaimer:
Data are incomplete because of the lag in time between when the death occurred and when the death certificate is completed, submitted to NCHS and processed for reporting purposes. This delay can range from 1 week to 8 weeks or more, depending on the jurisdiction and cause of death.
Some of the decline is real, because NYC hospitals aren’t running out of body bags nowadays, but much of it seems due to the paperwork not catching up with reality.
Judging from the slope of the Johns Hopkins summary of daily cases in the US, corroborated by the CNN projections, the doubling time (before the most recent increases) runs around four weeks: five million cases by the end of July and ten million by the end of August. Later this year, we’ll know how well saying “It’ll be gone by AprilsummerElection Day 2021″ without doing anything has worked out for us.
The overall death rate should decline in a few years, because those (of us?) who died early will reduce the later rate, but it’s not something to look forward to.
Dutchess County has another Household Hazmat / Electronics Disposal Day coming up, so I harvested some useful parts from the three dead dehumidifiers lurking under the bench.
The (perfectly good) blower motor in one unit lives inside a convenient plastic housing:
Scrap Dehumidifier Blower Motor – housing
It’s sitting on three foam pads hot-melt glued to three wood blocks cut to fit inside three convenient molded features, making it nice & quiet & stable.
I lashed it together with a chopped-off IEC cord, because the stock dehumidifier cords are just way too stiff. The motor and blower originally pulled air through the dust filter, the condenser, and the evaporator, before blowing it out the side, so it’s running pretty much unloaded. A quick test shows there’s not much difference between the high and low speeds:
High: 1050 RPM, 80 W, 12.5 m/s air flow
Low: 1000 RPM, 77 W, 11.7 m/s air flow
Low speed seems slightly less noisy, but the wiring now has insulated QD connectors just in case I ever want to run it at full speed.
For whatever it’s worth, the most recent dehumidifier failed one year into a two year warranty, but the company decided it was simpler to just refund the purchase price than to replace the unit. It seems the “sealed system” inside loses its refrigerant after a year and there’s no practical way to seal a small leak and recharge the system; unlike an automotive air conditioner, the tubes are soldered shut after the initial charge.
They all sport Energy Star badges, but throwing away the whole damned thing every year or two tells me we’re not measuring the right values. Obviously, somebody could make a worthwhile dehumidifier, but as of now Frigidare, GE Appliances (sold to Haier), and Danby are on my shit list. Next year, I expect to add HomeLabs to the list, because the dehumidifier is identical to the Danby unit (and, ah-ha comes with a 2.5 year warranty). They’re all made by Haier (or another Chinese factory) and nobody applies any long-term QC to their products.
The Smell of Molten Projects in the Morning 