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.
After pausing to recover from construction, Ms Robin laid four eggs in four days:
She’s surprisingly tolerant of our comings and goings, as well as garage door openings and closings:
We’re trying to stay out of her way as much as possible.
The gallery pix come from my phone, held against the soffit over the nest, and aimed entirely by feel, while standing on the Greater Ladder. If I had access to the top of the soffit, I’d drill a webcam hole, but …
This makes writing 3D modeling code and turning threads look downright attractive:
The previous owners apparently surrounded a cedar (?) tree with a ring of large, decorative rocks. The tree vanished long before we arrived, with the stump accreting random stones, bricks, and similar impedimenta ever since; my first task involved (re)moving a couple hundred pounds of rocky debris.
After using the stump as a fulcrum for that steel bar to break the rotted roots and loosen the surrounding soil, it’s out and away:
Back to the Basement Laboratory …
While I was cutting threads for the Floor Lamp poles, I tried measuring my progress over wires:
Those are three lengths of music wire, slightly bent from their storage roll, held in place with a precision clamp metric micrometer. Given the crudity of the setup, the uncalibrated wire diameter, and my lack of thread-fu, the results came out both close and unconvincing.
A set of real thread measuring wires being cheap & readily available, I’m prepared for the next time around this block:
The 185 mil “wires” (they’re all allegedly ground rod) will let me cut threads matching things like a Jesus nut; they’re suited for 3 TPI / 8 mm pitch screws. Mostly, wires from the front row will be all I ever need.
Which look like this in action:
The black doodad (the set includes half a dozen for all the wire sizes) fits over the micrometer anvil and holds two wires betwixt anvil and screw, leaving me to manipulate the screw, the third wire, and the micrometer with my remaining hands. Hence the vise holding the micrometer, which is known to be Very Bad Practice.
From the side:
All of the smaller wires measure 0.5 mil too thin, which is likely due to my lack of calibrated measurement equipment:
The few thread pitch diameters I measured also came out slightly too small, again likely due to calibration and screw tolerances.
The LittleMachineShop description of measuring threads over wires seems entirely adequate.
To forestall link rot, a slightly rearranged version of their tables of wire constants:
The lower table has metric thread pitches with the wire sizes in inches.
You measure the distance over the recommended wire (in inches or millimeters, as appropriate), subtract the constant, and get the pitch diameter in the same units. Conversely, add the constant to the desired pitch diameter to get the target over-wire distance, carefully cut the thread until it measures a bit less than that, back up sixty seconds, and cut it spot on.
Verily, it is written: there is no UnDo key (⎌) in machine shop work.
Even though I’m using what seem to be good-quality parts, one of the WS2812 RGB LEDs in a Glass Tile frame died:
It passed the Josh Sharpie Test:
After building the third Glass Tile unit, one of the LEDs didn’t light up due to an easily diagnosed problem:
A closer look:
Shortly thereafter, the Nissan Fog Lamp developed an obvious beam problem:
The WS2812 had the proper voltages / signals at all its pins and was still firmly stuck to the central “heatsink”:
It also passed the Josh Sharpie Test:
I’m particularly surprised by this one, because eleven of the twelve flex-PCB WS2812s in the Hard Drive Platter light have been running continuously for years with no additional failures.
The alert reader will note the common factor: no matter what substrate the LED is (supposed to be) soldered to, no matter when I bought it, no matter what it’s wired into, a WS2812 will fail.
They’re all back in operation:
Although nobody knows for how long …
Obviously, it’s time to refresh my programmable RGB LED stockpile!
More than a year later, the PiHole continues to work fine, but the process for installing the Cloudflare DoH machinery has evolved.
(And, yes, it’s supposed to be DNS-over-HTTPS. So it goes.)
To forestall link rot, the key points:
cd /tmp ; wget https://bin.equinox.io/c/VdrWdbjqyF/cloudflared-stable-linux-arm.tgz
tar -xvzf cloudflared-stable-linux-arm.tgz
sudo cp cloudflared /usr/local/bin
sudo chmod +x /usr/local/bin/cloudflared
sudo cloudflared -v
sudo useradd -s /usr/sbin/nologin -r -M cloudflared
sudo nano /etc/default/cloudflared
----
CLOUDFLARED_OPTS=--port 5053 --upstream https://1.1.1.1/dns-query --upstream https://1.0.0.1/dns-query
----
sudo chown cloudflared:cloudflared /etc/default/cloudflared
sudo chown cloudflared:cloudflared /usr/local/bin/cloudflared
sudo nano /etc/systemd/system/cloudflared.service
----
[Unit]
Description=cloudflared DNS over HTTPS proxy
After=syslog.target network-online.target
[Service]
Type=simple
User=cloudflared
EnvironmentFile=/etc/default/cloudflared
ExecStart=/usr/local/bin/cloudflared proxy-dns $CLOUDFLARED_OPTS
Restart=on-failure
RestartSec=10
KillMode=process
[Install]
WantedBy=multi-user.target
----
sudo systemctl enable cloudflared
sudo systemctl start cloudflared
sudo systemctl status cloudflaredThen aim PiHole’s DNS at 127.0.0.1#5053. It used to be on port #54, for whatever that’s worth.
Verify it at https://1.1.1.1/help, which should tell you DoH is in full effect.
To update the daemon, which I probably won’t remember:
wget https://bin.equinox.io/c/VdrWdbjqyF/cloudflared-stable-linux-arm.tgz
tar -xvzf cloudflared-stable-linux-arm.tgz
sudo systemctl stop cloudflared
sudo cp ./cloudflared /usr/local/bin
sudo chmod +x /usr/local/bin/cloudflared
sudo systemctl start cloudflared
cloudflared -v
sudo systemctl status cloudflaredAnd then It Just Works … again!
After five gardening seasons, my simple 3D printed wrench broke:
Although Jason’s comment suggesting carbon-fiber reinforcing rods didn’t prompt me to lay in a stock, ordinary music wire should serve the same purpose:
The pins are 1.6 mm diameter and 20 mm long, chopped off with hardened diagonal cutters. Next time, I must (remember to) grind the ends flat.
The solid model needs holes in appropriate spots:
Yes, I’m going to put round pins in square holes, without drilling the holes to the proper diameter: no epoxy, no adhesive, just 20 mm of pure friction.
The drill press aligns the pins:
And rams them about halfway down:
Close the chuck jaws and shove them flush with the surface:
You can see the pins and their solid plastic shells through the wrench stem:
Early testing shows the reinforced wrench works just as well as the previous version, even on some new valves sporting different handles, with an equally sloppy fit for all. No surprise: I just poked holes in the existing model and left all the other dimensions alone.
The OpenSCAD source code as a GitHub Gist:
| // Hose connector knob | |
| // Ed Nisley KE4ZNU – June 2015 | |
| // 2020-05 add reinforcing rods | |
| Layout = "Build"; // [Knob, Stem, Show, Build] | |
| RodHoles = true; | |
| //- Extrusion parameters – must match reality! | |
| /* [Hidden] */ | |
| ThreadThick = 0.25; | |
| ThreadWidth = 0.40; | |
| function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); | |
| Protrusion = 0.1; | |
| HoleWindage = 0.2; | |
| //—— | |
| // Dimensions | |
| /* [Dimensions] */ | |
| RodOD = 1.6; | |
| RodAngle = 35; | |
| /* [Hidden] */ | |
| StemOD = 30.0; // max OD for valve-to-valve clearance | |
| BossOD = 16.0; // single-ended handle boss | |
| SlotWidth = 13.0; | |
| SlotHeight = 10.0; | |
| StemInset = 10.0; | |
| StemLength = StemInset + SlotHeight + 25.0; | |
| StemSides = 2*4; | |
| Align = 0*180/StemSides; // 1* produces thinner jaw ends | |
| KnobOD1 = 70; // maximum dia without chamfer | |
| KnobOD2 = 60; // top dia | |
| KnobSides = 4*4; | |
| DomeHeight = 12; // dome shape above lobes | |
| KnobHeight = DomeHeight + 2*SlotHeight; | |
| DomeOD = KnobOD2 + (KnobOD1 – KnobOD2)*(DomeHeight/KnobHeight); | |
| DomeArcRad = (pow(KnobHeight,2) + pow(DomeOD,2)/4) / (2*DomeHeight); | |
| RodBCD = (StemOD + BossOD)/2; | |
| //- Adjust hole diameter to make the size come out right | |
| module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes | |
| Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2); | |
| FixDia = Dia / cos(180/Sides); | |
| cylinder(r=(FixDia + HoleWindage)/2,h=Height,$fn=Sides); | |
| } | |
| //– Stem for valve handles | |
| module Stem() { | |
| difference() { | |
| rotate(Align) | |
| cylinder(d=StemOD,h=StemLength,$fn=StemSides); | |
| translate([0,0,SlotHeight/2 – Protrusion/2]) | |
| cube([2*StemOD,SlotWidth,(SlotHeight + Protrusion)],center=true); | |
| translate([0,0,-Protrusion]) | |
| cylinder(d=BossOD,h=SlotHeight,$fn=2*StemSides); | |
| if (RodHoles) | |
| for (i=[-1:1]) | |
| rotate(i*RodAngle + 90) | |
| for (j=[-1,1]) | |
| translate([j*RodBCD/2,0,-Protrusion]) | |
| rotate(180/4) | |
| PolyCyl(RodOD,2*SlotHeight,4); | |
| } | |
| } | |
| //– Hand-friendly knob | |
| module KnobCap() { | |
| difference() { | |
| scale([1.0,0.75,1.0]) | |
| rotate(180/KnobSides) | |
| intersection() { | |
| translate([0,0,(KnobHeight-DomeArcRad)]) | |
| sphere(r=DomeArcRad,$fa=180/KnobSides); | |
| cylinder(r1=KnobOD1/2,r2=KnobOD2/2,h=KnobHeight,$fn=KnobSides); | |
| cylinder(r1=KnobOD2/2,r2=KnobOD1/2,h=KnobHeight,$fn=KnobSides); | |
| } | |
| translate([0,0,-Protrusion]) | |
| rotate(Align) | |
| cylinder(d=(StemOD + 2*ThreadWidth),h=(StemInset + Protrusion),$fn=StemSides); | |
| } | |
| } | |
| //- Build it | |
| if (Layout == "Knob") | |
| KnobCap(); | |
| if (Layout == "Stem") | |
| Stem(); | |
| if (Layout == "Build") { | |
| translate([-KnobOD1/2,0,0]) | |
| KnobCap(); | |
| translate([StemOD/2,0,StemLength]) | |
| rotate([180,0,0]) | |
| Stem(); | |
| } | |
| if (Layout == "Show") { | |
| translate([0,0,0]) | |
| Stem(); | |
| translate([0,0,StemLength – StemInset]) | |
| KnobCap(); | |
| } |
Having some interest in my Sony HDR-AS30 helmet camera’s NP-BX1 battery runtime, I’ve been measuring and plotting recharge versus runtime after each ride:
The vertical axis is the total charge in mA·h, the horizontal axis is the discharge time = recorded video duration. Because 1 A = 1 coulomb/s, 1 mA·h = 3.6 C.
The data points fall neatly on two lines corresponding to a pair of cheap USB testers:
When you have one tester, you know the USB current. When you have two testers, you’re … uncertain.
The upper tester is completely anonymous, helpfully displaying USB Tester while starting up. The lower one is labeled “Keweisi” to distinguish it from the myriad others on eBay with identical hardware; its display doesn’t provide any identifying information.
The back sides reveal the current sense resistors:
Even the 25 mΩ resistor drops enough voltage that the charger’s blue LED dims appreciably during each current pulse. The 50 mΩ resistor seems somewhat worse in that regard, but eyeballs are notoriously uncalibrated optical sensors.
The upper line (from the anonymous tester) has a slope of 11.8 mA·h/minute of discharge time, the lower (from the Keweisi tester) works out to 8.5 mA·h/minute. There’s no way to reconcile the difference, so at some point I should measure the actual current and compare it with their displays.
Earlier testing suggested the camera uses 2.2 W = 600 mA at 3.7 V. Each minute of runtime consumes 10 mA·h of charge:
10 mA·h = 600 mA × 60 s / (3600 s/hour)Which is in pretty good agreement with neither of the testers, but at least it’s in the right ballpark. If you boldly average the two slopes, it’s dead on at 10.1 mA·h/min; numerology can produce any answer you need if you try hard enough.
Actually, I’d believe the anonymous meter’s results are closer to the truth, because recharging a lithium battery requires 10% to 20% more energy than the battery delivered to the device, so 11.8 mA·h/min sounds about right.
Memo to Self: Trust, but verify.
The Smell of Molten Projects in the Morning 