Bafang BBS02: Speed Sensor Nut Reshaping

A Bafang BBS02 (for a friend’s upright bike) arrived with a deformed speed sensor nut:

Bafang BBS02 - Deformed speed sensor nut - end view
Bafang BBS02 – Deformed speed sensor nut – end view

It traveled halfway around the planet while trapped underneath the motor and, if it rode in the top layer or two of containers, the combination of pressure and heat would be irresistible.

The plastic was stiff and I couldn’t force the nut over the connector using as much force as seemed reasonable:

Bafang BBS02 - Deformed speed sensor nut - test assembly
Bafang BBS02 – Deformed speed sensor nut – test assembly

On the upside, the nut just compresses the silicone washer between the connector and the sensor to make a waterproof joint, so it need not have perfect threads or a uniform shape. Once the nut is in place, it will likely never be removed and should never bother anyone else.

Being unwilling to apply a hot-air gun near the cable, I decided to try slowly cold-forming the nut inside a mold:

Sensor Nut mold - solid model
Sensor Nut mold – solid model

The gap isn’t a kerf: the two halves meet to form a cylindrical pocket. The smaller holes fit a pair of brass tubes keeping the halves lined up while I arrange things:

Bafang BBS02 - Deformed speed sensor nut - clamp detail
Bafang BBS02 – Deformed speed sensor nut – clamp detail

A pair of swivel-pad clamps apply the pressure:

Bafang BBS02 - Deformed speed sensor nut - compression clamp
Bafang BBS02 – Deformed speed sensor nut – compression clamp

A few days of squashing made it round-er, whereupon I applied the clamp directly against the remaining high point with the other side cradled in the mold. It still doesn’t slide over the connector body, but I’m not in a rush.

Bafang tech support generously sent a speed sensor extension cable from which I can extract a good nut, which will require cutting and splicing the cable from the motor.

I’m still hoping gentle suasion will prevail.

The OpenSCAD source code tucks into the overall file producing various useful bits:

// Mold to reshape speed sensor nut

SensorNut = [0,14.4,13.0];
SensorMold = [SensorNut[OD] + 2*WallThick,SensorNut[OD] + 2*WallThick,SensorNut[LENGTH] + WallThick];
MoldSides = 20;
RodOD = 1.6;

module NutMoldBlock() {

    difference() {

        translate([0,0,SensorMold.z/2])
            cube(SensorMold,center=true);

        translate([0,0,WallThick])
            rotate(180/MoldSides)
                PolyCyl(SensorNut[OD],2*SensorNut[LENGTH],MoldSides);
        translate([0,0,-Protrusion])
            rotate(180/8)
                PolyCyl(SpeedOD,2*SensorMold.z,8);

        for (i=[-1,1])
            translate([i*(SensorMold.x/2 - WallThick/2),SensorMold.y,SensorMold.z/2])
                rotate([90,0,0])
                    PolyCyl(RodOD,2*SensorMold.y,6);
    }
}

module NutMold() {
    gap = 1.0;

    for (j=[-1,1])
        translate([0,j*gap,0])
            intersection() {
                translate([0,j*SensorMold.y,0])
                    cube(2*SensorMold,center=true);
                NutMoldBlock();
            }
}

… snippage …

if (Layout == "NutMold")
    NutMold();

I haven’t worked on a safety bike in years!

Rt 376 at Zack’s Way: Almost a Right Hook

I’m approaching Zack’s Way at about 20 mph when a truck appears to my left:

Rt 376 at Zacks Way - Right Hook Setup - 2021-06-04
Rt 376 at Zacks Way – Right Hook Setup – 2021-06-04

I cannot see the turn signals, but I’ve been around this block several times.

This time, however, what I know (and the driver apparently doesn’t) is that Zack’s Way has been closed for two days while a film crew does something to create The White House Plumbers along that stretch of road, with barricades and City of Poughkeepsie police cars across the entrance to prevent bystanders from wandering in.

At least I’ll have witnesses …

NYS DOT installed a pair of Variable Message Signs showing ZACK'S WAY | CLOSED | Thursday & Friday on either side of the intersection:

Rt 376 at Zacks Way - Closure VMS - 2021-06-04
Rt 376 at Zacks Way – Closure VMS – 2021-06-04

Fortunately, the driver figured it out before our paths crossed:

Rt 376 at Zacks Way - Right Hook Miss - 2021-06-04
Rt 376 at Zacks Way – Right Hook Miss – 2021-06-04

But, hey, those signs are easy to overlook, too …

I have typed “Zach’s Way”, rather than the correct “Zack’s Way”, on several posts.

Bicycle Helmet Mirror: Stalk Repair

The mirror on my bike helmet snagged on a mesh fence while walking the bike to Mary’s garden:

Helmet Mirror - bent stalk
Helmet Mirror – bent stalk

One of the good things about building your own stuff is that you have all the parts when something breaks:

Helmet Mirror - damaged parts
Helmet Mirror – damaged parts

The decorative M2 screw and insert pulled out of the ball. The rim of the nail set punch (intruding from the top) just barely caught the edge of the stub inside the ball, so a few taps could extract it. A Dremel cutoff wheel peeled the crumpled end off the stalk.

Reassembly proceeded without incident:

Helmet Mirror - installed
Helmet Mirror – installed

The bizarrely blurred mirror over on the left comes from the Pixel phone camera app deciding this was a Portrait, applying a background blur, and running into trouble with those hard edges in the foreground. The camera app has a distinct Portrait mode that, perhaps, I inadvertently engaged while fumbling around.

Tour Easy: Rear Fender Bracket Installed

A rainy day finally produced an opportunity to install the rear fender bracket on my bike:

Tour Easy Rear Fender Bracket - improved
Tour Easy Rear Fender Bracket – improved

It’s actually another iteration, tweaked to hold the fender snugly against the bracket, because it’s tucked in a location where I can’t measure anything.

The brake noodle isn’t connected yet, but it has plenty of room in front of the fender block.

Snapping Turtle on the Move

A snapping turtle headed toward the beaver pond on the Dutchess County Rail Trail:

Snapping Turtle - DCRT - 2021-05-26
Snapping Turtle – DCRT – 2021-05-26

At this time of year and phase of the moon, she is most likely in search of a good spot for a nest and her clutch of eggs. Being an aquatic creature, she and her progeny surely benefit from Team Beaver’s engineering.

Today I Learned: snappers are the New York State Official Reptile.

Bafang Programming Adapter: More Cable Colors

In the process of installing a Bafang BBS02 mid-drive motor on a friend’s diamond-frame bike, I discovered, once again, how little anybody cares about the colors inside cables:

Bafang Display Extension Cable - internal colors
Bafang Display Extension Cable – internal colors

The cheerful rainbow on the right is the stub end of the Bafang display extension cable I built into the previous adapter.

The new cable on the left seemed like it might match the canonical colors:

Bafang BBS02 display cable pinout
Bafang BBS02 display cable pinout

It comes heartbreakingly close:

Bafang Display Cable - extension colors
Bafang Display Cable – extension colors

Brown and Orange connect as the naive user might expect, which does reduce the likelihood of incinerating the motor controller / USB adapter / laptop by connecting the 48 V battery directly to the logic-level electronics.

However, White wasn’t on the original menu, Green is now TXD, and Black has become, comfortingly, GND.

Verily, it is written: Hell hath no fury like that of an unjustified assumption.

This socket connector has a watertight shell making it extremely difficult to mate and unmate with the pin connector on the bike. Watertightness being unnecessary, a little razor-knife action seems in order:

Bafang Display Extension Cable - shroud trimming
Bafang Display Extension Cable – shroud trimming

Visually, they’re both green-ish, but sometimes the Pixel camera accentuates any differences.

Rt 376 Knotweed

Last June, NYS DOT surprised us by clearing the Japanese Knotweed along Rt 376 just north of Maloney, then applying enough defoliant to keep it knocked back this Spring:

Rt 376 Knotweed - defoliation near Maloney - 2021-05-23
Rt 376 Knotweed – defoliation near Maloney – 2021-05-23

A year earlier, they clearcut the overgrowth beyond the guide rail from Red Oaks Mill southward, but without defoliant, and the Knotweed is off to a good start:

Rt 376 Knotweed - Knotweed growth - 2021-05-23
Rt 376 Knotweed – Knotweed growth – 2021-05-23

I’ll do my part, inadequate though my pruners may be:

Rt 376 Knotweed - Knotweed trimming - 2021-05-23
Rt 376 Knotweed – Knotweed trimming – 2021-05-23

I got most of the growth in front of the guide rail extending across the shoulder, but must wait for another weekend morning to hack back the main stems.

Unfortunately, Knotweed control requires nearly continuous clearcutting and defoliation to prevent new growth.