Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
I picked up a $35 LED bulb that’s allegedly equivalent to a 75 W incandescent, replacing a 100 W equivalent compact fluorescent bulb that an X10 relay switch couldn’t turn off cleanly, for a torchiere floor lamp. ‘Nuff said about early CFL failures.
It has both upward and downward facing LED chips that light up the diffuser and ceiling in equal measure. Both strings are visible from the side due to the heavy molded plastic lens around the chips:
LED Bulb
Some interesting bits from the package:
Home Depot LED Bulb Warranty
A 22.8 year lifespan at three hours per day works out to 24.983×103 hours. I wish I could have heard the arguments about whether they could claim a 23 year lifespan…
At the same duty cycle, the 5 year warranty covers 5.479×103 hours. Huh.
The URL at the bottom leads to some general info, but nothing you didn’t know already.
It works well enough, but at $35 it’s really a capital investment that I suspect will never actually pay for itself…
The DCRT folks held a “soft opening” last week at the bridge over Rt 55 completing the rail trail from Hopewell Junction to the Walkway Over the Hudson; the Hudson Valley Rail Trail continues westward to Lloyd. I hadn’t actually planned to ride the whole thing, but Monday was a lovely day and, hey, why not?
So here’s what a pleasant, mostly off-road 36 mile ride looks like:
KE4ZNU Rail Trail Ride – 2013-10-14
Hadn’t realized it was Columbus Day until well into the ride, which accounted for a Hudson River crossing at 3 mph embedded in a solid 1.5 mile scrum. Being no fool, I returned over the Poughkeepsie (a.k.a. Mid Hudson) Bridge.
The kitchen sink has a small faucet that used to connect directly to the well out back, but now delivers town water from a line bypassing the water softener. The large steel washer below the sink deck has been shedding rust for a while and finally disintegrated:
Kitchen faucet – rusted washer assembly
Well, this is a perfect application for plastic, not steel, so I conjured up a pair of disks:
Sink Base – Build
The large flat one goes below the sink deck in place of the steel washer and the smaller part of the stepped disk fits inside the deck opening to stabilize the faucet:
Sink Base – Show
The two dark rings bracketing the deck between the orange plastic disks represent a pair of gaskets / washers / seals cut from 1 mm rubber sheet with a straight razor toting compass:
Kitchen faucet – plastic disks and rubber deck washers
Just for fun, I used Slic3r’s Hilbert Curve top and bottom fill pattern. It produces a nice, grainy texture that feels appropriate for anything needing a non-slip grip (at least on the top, as the bottom surface is glass-smooth).
Everything stacks up thusly, with the top dark ring representing a rubber seal that came with the faucet:
Sink Base – Assemble
It looks about the same in real life, albeit minus all the colors:
Kitchen faucet – fitting stack
The black plastic and black rubber blend together and vanish amid all the chrome:
Kitchen faucet – assembled
Alas, when I turned the water on, Mary said “That doesn’t sound right…” at about the same time I discovered a fine mist under the sink. See if you can spot the problem:
Kitchen faucet – corroded copper tube
A shined-up view should make it obvious:
Kitchen faucet – corroded copper tube – pinhole
A trip to the precious metals aisle of the Big Box Home Repair Store produced a roll of 3/8 inch copper tubing, although I should have the stub end of that original roll somewhere in the heap. The fitting at the bottom of the faucet turned out to be completely non-standard and I had to re-use it with the new tubing, but it still sealed perfectly.
I hate plumbing jobs. That fix better last for another decade…
Fairly obviously, taping the Z-min switch to the back of the X gantry isn’t a long-term solution. There’s just enough clearance between the extruder and the X gantry for the switch, so I made a small block with clearance holes for the screws holding the X axis linear slide rail in place and tapping holes for the M2.5×0.45 screws in the switch:
Z-min Front Mount Switch Block – solid model
Not much to it, is there? That printed just fine with the taped-in-place switch and exactly fit the screws; the rail screws dropped right through the holes and the switch screws tapped their way in.
The stock M2 cable reaches to the front of the X gantry, but only with the switch mounted to the left side:
M2 Z-min switch – left gantry
Those are 25 mm M3 screws shortened to about 19 mm; the one on the right looks a bit short to me, too.
Unfortunately, that spot on the gantry is the only place you can pick up the M2 with one hand: it balances perfectly when you (well, I) put four fingers between the five leftmost rail screws. It’s a beast to carry any other way, so that switch had to move.
So I spliced in a snippet of six conductor cable, just so I could match the original color code, replaced the red through-hold LED with a blue SMD LED, and moved it to the middle of the gantry:
M2 Z-min switch – center gantry
The view from below shows a sticky clamp holding a bight of the original cable and a small clamp (bent & drilled from a steel strap) holding the new cable in place:
M2 Z-min switch – center gantry – bottom view
It’s once again possible to grab the printer and lug it away…
The first test piece was Madscifi’s classic Tiny Toy Dump Truck, because I needed a show-n-tell tchotchke for a Squidwrench meeting:
M2 Z-min switch – center gantry – in action
Yes, that dangling switch lever looks precarious, but it can’t touch the platform because the nozzle is below it.
With the switch in place, I melted a blob of solder atop the brass tubing on the platform, popped it off, and removed the residue with a razor scraper.
Before doing the truck, however, I had to recalibrate the Z switch and make the homing sequence do a different dance:
Home Y and leave the platform at the rear
Home X and move it to the far right to clear the platform
Home Z against the platform glass
The complete start.gcode sequence (which isn’t really a separate file in Slic3r, but the notation helps keep things straight):
;-- Slic3r Start G-Code for M2 starts --
; Ed Nisley KE4NZU - 7 Oct 2013
; Z-min switch at platform, must move nozzle to X=130 to clear platform
M140 S[first_layer_bed_temperature] ; start bed heating
G90 ; absolute coordinates
G21 ; millimeters
M83 ; relative extrusion distance
M84 ; disable stepper current
;G4 S3 ; allow Z stage to freefall to the floor
G28 Y0 ; home Y to be sure of clearing probe point in X
G92 Y-127 ; set origin to 0 = center of plate
G28 X0 ; home X
G92 X-95 ; set origin to 0 = center of plate
G1 X130 F30000 ; move off platform to right side
G28 Z0 ; home Z
G92 Z-4.55 ; set origin to measured z offset
G0 Z10 F2000 ; get nozzle clearance
G0 X0 Y-124 Z3.0 F20000 ; set up for priming
M190 S[first_layer_bed_temperature] ; wait for bed to finish heating
M109 S[first_layer_temperature] ; set extruder temperature and wait
G1 Z0.0 F2000 ; plug extruder on plate
G1 E10 F300 ; prime to get pressure
G1 Z5 F2000 ; rise above blob
G1 X5 Y-123 F30000 ; move away from blob
G1 Z0.0 F2000 ; dab nozzle to remove outer snot
G4 P1 ; pause to clear
G1 Z0.5 F2000 ; clear bed for travel
;-- Slic3r Start G-Code ends --
The G92 Z-4.55 instruction sets the Z position (without moving the stage) to the measured difference between the switch trip point and the nozzle tip.
Finding that value is a two-step process:
Manually home Z against the platform (with the nozzle off to the right!)
Issue G92 Z0 to define the switch trip point as Z=0.0
Move the Z stage downward by a known distance so it clears the nozzle
Move the nozzle over the platform
Measure the distance between nozzle and platform (perhaps with a tapered gauge)
Subtract that measurement from the distance you moved the nozzle
For example, I lowered the platform by 7.0 mm and measured 2.6 mm between the nozzle and the platform, so the G92 value = -7.0 + 2.6 = -4.4. Put that in the start.gcode G92 instruction: G92 Z-4.4.
That’ll get you in the ballpark, so print a thinwall open box and measure its top-to-bottom height at the corners. The second box came out about 4.85 mm tall, which means the nozzle was 0.15 mm too close to the platform: subtract 0.15 from the G92 setting: -4.4 – 0.15 = -4.55.
The next thinwall box came out exactly 5.0 mm tall.
Then I could print that truck, which came out just fine, apart from the usual slight drooping where the filament must bridge the left side of the dump box:
M2 Tiny Toy Dump Truck test piece
After breaking one errant strand from the left side of the hinge, everything moved smoothly.
I must tinker up some G-Code to measure the switch closure point along the length of the platform, which would detect front-to-back tilt.
The OpenSCAD source code for the switch mounting block:
// Block to mount M2 Z-min switch on X gantry
// Ed Nisley KE4ZNU - Oct 2013
//- Extrusion parameters - must match reality!
ThreadThick = 0.25;
ThreadWidth = 0.40;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
Protrusion = 0.1;
HoleWindage = 0.2;
//- Sizes
SwitchScrewOD = 2.05; // microswitch screw tapping
SwitchScrewOC = 9.5; // ... on-center spacing
GantryScrewOD = 3.0; // X rail screw clearance
GantryScrewOC = 25.0; // ... on-center spacing along X
GantryScrewOffset = 12.0; // ... Y offset from gantry front
BlockSize = [1.5*GantryScrewOC,17.0,5.0]; // XYZ dimensions as mounted
SwitchScrewLength = BlockSize[1] - 5*ThreadWidth; // net length of switch screws
echo ("Max switch screw length: ",SwitchScrewLength + 5.0); // ... allow switch thickness
//- 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);
}
//- Put peg grid on build surface
module ShowPegGrid(Space = 10.0,Size = 1.0) {
RangeX = floor(100 / Space);
RangeY = floor(125 / Space);
for (x=[-RangeX:RangeX])
for (y=[-RangeY:RangeY])
translate([x*Space,y*Space,Size/2])
%cube(Size,center=true);
}
//- Build it
ShowPegGrid();
difference() {
translate([-BlockSize[0]/2,-GantryScrewOffset,0])
cube(BlockSize,center=false);
for (i=[-1,1]) {
translate([i*GantryScrewOC/2,0,-Protrusion])
rotate(-90)
PolyCyl(GantryScrewOD,(BlockSize[2] + 2*Protrusion));
translate([i*SwitchScrewOC/2,-(GantryScrewOffset + Protrusion),BlockSize[2]/2])
rotate([-90,0,0])
rotate(90)
PolyCyl(SwitchScrewOD,(SwitchScrewLength + Protrusion));
}
}
Back in the early 1950s, Anderson’s state-of-the-art awning windows had screens on the inside: you must open the screen to open or close the window. This surely seemed like a good idea at the time, but in practice we don’t open the screen very much, very often, during peak insect season, as insects tend to collect on the outer surface.
We’ve learned to live with the smaller bugs, but this critter gave me pause one evening:
Hunting Spider on Window Screen
It’s a Hunting Spider (or, more exactly, a Wolf Spider), perched on the outside of the screen, inside the (opened) window. The (hard inch) screen grid is about 70×55 mils, so those legs span about 2-1/8 inch, call it 55 mm.
We’re big fans of spiders, but this portends a bit more intimacy than I’m comfortable with. I blew through the screen to tickle its tummy until it moved outside the window frame, then opened the screen and closed the window without pause.
Wake up with one of those on your pillow and tell me how it works for you.
I donated the last of Mad Phil’s stuff to a local nonprofit’s tag sale, where it helped bulk up the bottom line a bit. While I unpacked the van, a grasshopper stopped by to supervise:
The Smell of Molten Projects in the Morning 