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.
Canada Geese seem primed to travel in a straight line, whether in the air, on water, along a rail trail, or even on a sidewalk:
They proceed around corners in an orderly manner:
But they completely ignore crosswalk markings:
We think two goose families joined forces for this outing: four large geese and seven goslings by our count.
The sidewalks sport a rich assortment of goose poop, so the geese obviously enjoy their hikes.
Start with the amber side marker light sporting a cataract and distorted beam:
Part off the lens:
The cut is just in front of the PCB and went slowly to avoid clobbering the SMD resistors very near the edge.
The cataract turned out to be crud adhered to the LED lens:
Brutal surgery removed the LED and installed a replacement:
The PCB had two 150 Ω SMD resistors for use with 12-ish V automotive batteries. While I had the hood up, I removed one and shorted across its pads to make the LED work with the 6 V switched headlight supply from the Bafang motor.
In round numbers, 6 V minus 2.2 V forward drop divided by 150 Ω is about 25 mA. The original LED ran at 35-ish mA, but it’s close enough.
Glue the lens back in place:
The bubbly stuff is solid epoxy from the original assembly, which is why removing the PCB is not an option.
The new LED is no more off-center than any of the others:
It does, however, sit much closer to the lens, due to the ring of plastic I cut away to get inside. As a result, the beam is mostly a single centered lobe with only hints of the five side lobes; there isn’t much waste light from the side of the LED into those facets.
Replace the one I originally put in the new fairing mount:
However, it’s still not much more than a glowworm in the daytime, so we need more firepower …
We woke just after midnight to a completely dark and silent house, I padded around shutting of half a dozen UPS units under various desks and benches, and we eventually got back to sleep:
According to our clocks, power actually returned about four hours later.
Our grocery ride the next morning went past the crash site:
Tracks in the grass leading up to the smashed mailbox on our right suggest the driver didn’t quite make the very slight curve leading to the straight section.
It was garbage collection day and the debris field covered the entire front lawn:
Both poles have rectangular reflectors, but the one on the smashed pole (on the left) shows the pole is maybe four feet shorter than it used to be.
We have no idea how a can of white paint got involved in the proceedings:
[Update: Now we know where the paint came from.]
Quite some years ago, an errant driver demolished the front corner of that house and, more recently, the whole building burned out, so there may be a jinx on the site.
Other than that, we had an uneventful ride …
The Bafang battery charger uses an AC line cord “binocular” connector with what must be the weakest spring contacts ever made, which finally annoyed me enough to fix:
Also, the case now sports four thick fuzzy felt feet to keep it from sliding around quite so easily.
Another customer-does-the-last-ten-percent product …
Spotted behind a mall undergoing renovation:
Perhaps they were loading it from the end and didn’t notice the instructions:
Protip: Always get the biggest dumpster available!
With the Bafang BBS02 and all its gimcrackery on the Terry Symmetry buttoned up and ready to go, I took a few closeout pictures for future reference.
The motor has a sheaf of wires sticking out of the bottom crying out for a protective covering:
Although cameras tell only the truth they’re allowed to see and can be made to lie by omission, sometimes their latent truth was completely invisible to eyewitnesses in real time.
I only noticed the mis-routed shift cable when I looked through the last set of pictures.
It should pass through the plastic channel under the metal tab holding the cable guide to the bottom bracket shell:
Normally, aiming the cable into the channel is no big deal. In this case, I had to undo the shift cable, remove the left crank, loosen the motor and rotate it out of the way, nudge the cable with a small screwdriver, then reinstall in reverse order.
Dang, that was close …
The original BBS02 reaction spacer for Gee’s Terry Symmetry didn’t work quite the way I expected:
The motor evidently vibrates enough to propel the block forward, shearing the double-sticky foam tape which was never intended to resist force in that plane. I thought the block was located at the point where the motor casing was tangent to the frame tube, so as to equalize the forces in both directions, but … nope.
A revised design based on measurements informed by new knowledge:
The upper curve is now symmetric and the whole block mounts more rearward under the bottom bracket lug, where some tedious work with a machinists square located the real tangent point:
The motor sure doesn’t look like it’s tangent, but a dry fit showed all the curves laid against the case and tubes.
The brazing fillet means the step fitting the downtube can’t sit snug against the edge of the lug, but most of the reaction force should go through the section into the lug, near the center of the block.
A crude marker will keep track of any motion:
I think the symmetric curve against the motor has enough projection to keep the block from wandering off, even if I haven’t gotten the location exactly right.
Stipulated: Hope is not a strategy.
The OpenSCAD source code:
MotorOD = 111; // motor frame dia
MotorOffset = 10.0; // motor OD tangent wrt lug edge
ShiftSpace = 6.0; // motor to frame space
LugLength = 25.0; // length of section over BB lug
Spacer = [5.0 + LugLength,DownTube[ID]/2,4*ShiftSpace];
SpaceAngle = 0*atan(1.8/Spacer.x); // tilt due to non-right-angle meeting
echo(str("Spacer angle: ",SpaceAngle));
module MotorSpacer() {
difference() {
translate([LugLength - Spacer.x/2,0,0])
cube(Spacer,center=true);
translate([0,0,DownTube[ID]/2])
rotate([0,90 + SpaceAngle,0]) rotate(180/FrameSides)
cylinder(d=DownTube[ID],h=DownTube[LENGTH],$fn=FrameSides,center=true);
translate([DownTube[LENGTH]/2,0,DownTube[ID]/2 - DownTube[LENGTH]*sin(SpaceAngle)/2]) // concentric with ID
rotate([0,90 + SpaceAngle,0]) rotate(180/FrameSides)
cylinder(d=DownTube[OD],h=DownTube[LENGTH],$fn=FrameSides,center=true);
translate([MotorOffset,0,-(MotorOD/2 + ShiftSpace)])
rotate([90,0,0]) rotate(180/48)
cylinder(d=MotorOD,h=2*Spacer.y,$fn=48,center=true);
}
}
Nothing like actual riding to reveal what needs more thought!
The Smell of Molten Projects in the Morning 