Category: Recumbent Bicycling

Cruisin’ the streets

Tour Easy: SRAM X.0 Rear Grip Shifter

With more snow on the schedule, Mary’s bike finally got a new rear shifter:

Tour Easy – SRAM X.0 grip shifter installed

It’s an old-school SRAM X.0 grip shifter, evidently compatible with SRAM X.9 and X.7 derailleurs, and seems to work OK. The wavy ridges may be more prominent than necessary for our road riding, though.

In a miracle of rare device, the preinstalled cable turned out to be exactly long enough:

Tour Easy – SRAM X.0 cable length

Twiddling the length for perfect shifting requires on-the-road testing and the chain wrap may need tweaking (I may not have gotten it right when I installed the derailleur), but at least the shifter stops at every detent along the way.

2019-03-02

SJCAM M20 Camera: Tour Easy Seat Mount

The general idea is to replace this:

M20 in waterproof case - Tour Easy seat — M20 in waterproof case – Tour Easy seat

With this:

SJCAM M20 Mount - Tour Easy side view — SJCAM M20 Mount – Tour Easy side view

Thereby solving two problems:

Pitifully small battery capacity
Wobbly camera support

The battery is an Anker PowerCore 13000 Power Bank plugged into the M20’s USB port. Given that SJCAM’s 1 A·h batteries barely lasted for a typical hour of riding, the 13 A·h PowerCore will definitely outlast my legs. The four blue dots just ahead of the strap around the battery show it’s fully charged and the blue light glowing through the case around the M20 indicates it’s turned on.

The solid model has four parts:

SJCAM M20 Mount - Fit layout — SJCAM M20 Mount – Fit layout

Which, as always, incorporates improvements based on the actual hardware on the bike.

A strap-and-buckle belt harvested from a defunct water pack holds the battery into the cradle and the cradle onto the rack, with a fuzzy velcro strip stuck to the bottom to prevent sliding:

SJCAM M20 Mount - Tour Easy rear view — SJCAM M20 Mount – Tour Easy rear view

The shell around the camera is basically a box minus the camera:

SJCAM M20 Mount - Show - shell — SJCAM M20 Mount – Show – shell

The shell builds as three separate slabs, with the center section having cutouts ahead of the camera’s projections to let it slide into place:

SJCAM M20 Mount - Show - shell sections — SJCAM M20 Mount – Show – shell sections

The new shell version is 30.5 mm thick, so a 40 mm screw will stick out maybe 5 mm beyond the nylon locknut. I trust the screws will get lost in the visual noise of the bike.

A peg sticking out behind the USB jack anchors the cable in place:

SJCAM M20 Mount - Show - shell sections - USB side — SJCAM M20 Mount – Show – shell sections – USB side

The front slab and center top have curves matching the M20 case:

SJCAM M20 Mount - Show - shell sections - button side — SJCAM M20 Mount – Show – shell sections – button side

The camera model has a tidy presentation option:

SJCAM M20 Mount - Show - M20 body — SJCAM M20 Mount – Show – M20 body

And an ugly option to knock the protruberances out of the shell:

SJCAM M20 Mount - Show - M20 body - knockouts — SJCAM M20 Mount – Show – M20 body – knockouts

The square-ish post on the base fits into an angled socket in the clamp around the seat rail:

SJCAM M20 Mount - Show - clamp — SJCAM M20 Mount – Show – clamp

The numbers correspond to the “Look Angle” of the socket pointing the camera toward overtaking traffic. The -20° in the first clamp shows a bit too much rack:

SJCAM M20 Mount - first ride - traffic - 2019-02-06 — SJCAM M20 Mount – first ride – traffic – 2019-02-06

It may not matter, though, as sometimes you want to remember what’s on the right:

SJCAM M20 Mount - first ride - 2019-02-06 — SJCAM M20 Mount – first ride – 2019-02-06

FWIW, the track veering off onto the grass came from a fat-tire bike a few days earlier. Most of the rail trail had cleared by the time we tried it, with some ice and snow in rock cuts and shaded areas.

Contrary to the first picture, I later remounted the camera under the seat rail with its top side downward. The M20 has a “rotate video” mode for exactly that situation, which I forgot to turn off in the fancy new mount, so I rotated the pix afterward.

A 3 mm screw extends upward through the hole in the socket to meet a threaded brass insert epoxied into the shell base, as shown in the uglified M20 model. Despite appearances, the hole is perpendicular to both the socket and the shell, so you can tweak the Look Angle without reprinting the shell.

All in all, the mount works well. We await better riding weather …

The OpenSCAD source code as a GitHub Gist:

	// SJCAM M20 Camera Mount for Tour Easy seat back rail
	// Ed Nisley – KE4ZNU
	// 2019-02

	/* [Layout Options] */

	Layout = "Fit"; // [Show,Fit,Build]

	Part = "Shell"; // [Cradle,Shell,Clamp,ShellSections,M20,Interposer,Battery,Buttons]

	LookAngle = [0,5,-25]; // camera angle, looking backwards


	/* [Extrusion Parameters] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	ClampScrew = [5.0,10.0,50.0]; // ID=thread OD=washer LENGTH=total
	ClampInsert = [5.0,7.5,10.5]; // brass insert

	MountScrew = [3.0,7.0,23]; // ID=thread OD=washer LENGTH=tune to fit clamp arch
	MountInsert = [3.0,4.95,8.0]; // ID=screw OD, OD=knurl dia

	EmbossDepth = 2*ThreadThick + Protrusion; // recess depth + Protrusion beyond surface

	DebossHeight = EmbossDepth; // text height + Protrusion into part

	Projection = 10; // stick-out to punch through shell sides & suchlike

	SupportColor = "Yellow";
	FadeColor = "Green";
	FadeAlpha = 0.25;

	//—–
	// Useful routines

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	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);
	}

	//—–
	// M20 Camera
	// Looks backwards from seat = usual right-hand coordinates work fine
	// X parallel to bike frame, Y parallel to seat strut, Z true vertical

	M20 = [24.5,40.5,54.0];

	M20tm = 4.0; // chord height at top of case
	M20tr = (pow(M20tm,2) + pow(M20.y,2)/4) / (2*M20tm); // … radius
	echo(str("Top radius: ",M20tr));

	M20TopSides = 334;
	echo(str(" … sides: ",M20TopSides));

	M20fm = 1.0; // chord height at front of case
	M20fr = (pow(M20fm,2) + pow(M20.y,2)/4) / (2*M20fm); // … radius
	echo(str("Front radius: ",M20fr));

	M20FrontSides = ceil(M20fr / M20tr * M20TopSides); // make arc sides match up
	echo(str(" … sides: ",M20FrontSides));

	Lens = [19.0,22.5,5.5]; // ID=optical element, OD=tube
	LensBezel = [23.0,24.5,2.5]; // ID=lens tube, OD=bezel
	LensOffset = [-M20fm,0,41.5]; // bottom of case to lens centerline

	LensCap = [Lens[OD],24.5,4.5]; // silicone lens cap

	Spkr = [0.75,M20.y,14.3]; // speaker recess below LCD

	Switch = [8.0,1.0,38.0]; // selection switches
	SwitchOffset = [9.0,0,0]; // from rear to center of switches

	Jack = [10.0,0.1,36.0]; // jack and MicroSD card access, slightly enlarged
	JackOffset = [10.0,0,30.0]; // rear, bottom to center of jack block

	USB = [JackOffset.x – Jack.x/2,20.0,10.0]; // strut under USB plug
	USBOffset = [0,0,33.5]; // bottom to center of jack

	SDCard = [2.0,0.1,12.0]; // SD Card slot
	SDOffset = [9.0,0,20.0]; // bottom, rear to center of slot

	Button = [8.5,10.5,M20tm]; // ID = button, OD = bezel
	ButtonOC = 18.0; // on-center Y separation, assume X centered

	Screen = [0.1,31,24]; // LCD on rear face
	ScreenOffset = [0,0,33];

	BarLEDs = [0.1 + M20fm,12.0,5.0]; // Bar LEDs on front face
	BarLEDsOffset = [-M20fm,0,12.5];

	PwrLED = [3.5,3.5,0.1 + M20tm]; // power LED on top
	PwrLEDOffset = [2.5,0,0];

	RearLEDs = [1.0,2.0,0.1]; // charge and power LED openings above LCD
	RearLEDsOffset = [0,13.0/2,M20tm + 3.0]; // .. from top center of case

	module Buttons(KO) {
	for (j = [-1,1])
	translate([0,j*ButtonOC/2,0]) {
	cylinder(d=Button[OD],h=Button[LENGTH],$fn=12);
	if (KO)
	translate([0,0,M20tm])
	cylinder(d1=Button[OD],d2=1.5*Button[OD],h=Button.z,$fn=12);
	}
	}

	module M20Shape(Knockout = false) {

	difference() {
	intersection() {
	translate([0,0,M20.z/2 – M20tr]) // top curve
	rotate([0,90,0]) rotate(180/M20TopSides)
	cylinder(r=M20tr,h=2*(M20.x + Protrusion),$fn=M20TopSides,center=true);
	translate([M20.x/2 – M20fr,0,0])
	rotate(180/M20FrontSides)
	cylinder(r=M20fr,h=2*M20.z,$fn=M20FrontSides,center=true);
	cube(M20,center=true);
	}
	translate([Spkr.x/2 – M20.x/2 – Protrusion,0,Spkr.z/2 – Protrusion/2 – M20.z/2])
	cube(Spkr + [Protrusion,2*Protrusion,Protrusion],center=true);
	}

	translate([M20.x/2,0,-M20.z/2] + LensOffset)
	rotate([0,90,0])
	cylinder(d=Lens[OD] + HoleWindage,h=(Knockout ? Projection : Lens[LENGTH]),$fn=443,center=false);

	translate([M20.x/2 + M20fm/2,0,-M20.z/2] + LensOffset) // lens bezel
	rotate([0,90,0])
	cylinder(d1=LensBezel[OD],d2=Lens[OD],h=LensBezel[LENGTH],$fn=443,center=false);

	translate([-M20.x/2 + SwitchOffset.x, // side switches
	-(Switch.y + M20.y – Protrusion)/2,
	0])
	cube(Switch + [0,Protrusion,0] + (Knockout ? [0,Projection,0] : [0,0,0]),center=true);

	if (Knockout)
	translate([(M20.x/2 – M20fm)/2,-M20.y/2,0]) // side switch slide-in clearance
	cube([M20.x/2 – M20fm,2*Switch.y,Switch.z],center=true);

	translate([-M20.x/2 + JackOffset.x,
	(Jack.y + M20.y – Protrusion)/2,
	JackOffset.z – M20.z/2])
	cube(Jack + [0,Protrusion,0] + (Knockout ? [0,Projection,0] : [0,0,0]),center=true);

	translate([0,0,M20.z/2 – M20tm]) // top control buttons
	Buttons(Knockout);

	if (Knockout)
	translate([(M20.x – M20fm)/4,0,M20.z/2 – M20tm + Button[LENGTH]/2]) // slide-in button clearance
	cube([(M20.x – M20fm)/2,ButtonOC + Button[OD],Button[LENGTH]],center=true);

	translate([-(M20.x + Screen.x – Protrusion)/2,0,-M20.z/2] + ScreenOffset)
	cube(Screen + [Protrusion,0,0] + (Knockout ? [Projection,0,0] : [0,0,0]),center=true);

	for (j = [-1,1])
	translate([-M20.x/2 + Protrusion,j*RearLEDsOffset.y,M20.z/2 – RearLEDsOffset.z])
	rotate([0,-90,0]) rotate(180/6)
	PolyCyl(RearLEDs[OD],Knockout ? Projection : RearLEDs[LENGTH],6);

	translate([M20.x/2 + BarLEDs.x/2,0,-M20.z/2] + BarLEDsOffset)
	cube(BarLEDs + (Knockout ? [Projection,0,0] : [0,0,0]),center=true);

	translate([0,0,M20.z/2 – M20tm] + PwrLEDOffset)
	rotate(180/8)
	PolyCyl(PwrLED[OD],(Knockout ? Projection : PwrLED[LENGTH]),8);

	if (Knockout) {
	translate([0,0,-M20.z/2])
	rotate([180,0,0]) { // mounting screw
	PolyCyl(MountScrew[ID],MountScrew[LENGTH],6);
	translate([0,0,MountScrew[LENGTH] – Protrusion])
	PolyCyl(MountScrew[OD],MountScrew[ID] + 4*ThreadThick,6); // SHCS head is about 1 ID long
	}

	translate([0,0,-(M20.z/2 + MountInsert[LENGTH] + 4*ThreadWidth – Protrusion)])
	PolyCyl(MountInsert[OD],MountInsert[LENGTH] + 4*ThreadWidth,6); // insert inside Interposer
	}

	}

	//—–
	// Shell
	// Wraps around camera

	NomWall = 3.0;

	ShellWall = [IntegerMultiple(NomWall,ThreadThick),
	IntegerMultiple(NomWall,ThreadWidth),
	IntegerMultiple(NomWall,ThreadWidth)];
	ShellRadius = ShellWall.x;
	ShellSides = 8;

	ShellOA = M20 + 2*ShellWall;
	echo(str("Shell OA: ",ShellOA));

	Interposer = [M20.x – M20fm,M20.x – M20fm,10.0]; // if you can't be smart, be square

	module Shell() {

	Screw = [3.0,6.75,30]; // ID=thread OD=washer LENGTH
	ScrewClear = 1.0; // additional washer clearance
	ScrewSides = 8;

	ScrewOC = M20 + [0,Screw[ID]/cos(180/ScrewSides),Screw[ID]/cos(180/ScrewSides)]; // use PolyCyl hole dia, ignore .x value

	difference() {
	union() {
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i(ShellOA.x – 2ShellRadius)/2,
	j(ShellOA.y – 2ShellRadius)/2,
	k(ShellOA.z – 2ShellRadius)/2])
	sphere(r=ShellRadius/cos(180/ShellSides),$fn=ShellSides); // fix low-poly approx radius

	for (j=[-1,1], k=[-1,1]) // screw bosses, full length
	translate([0,jScrewOC.y/2,kScrewOC.z/2])
	rotate([0,90,0]) rotate(180/ScrewSides)
	cylinder(d=Screw[OD] + ScrewClear,h=ShellOA.x,center=true,$fn=ScrewSides);

	translate([-(ShellOA.x – USB.x – ShellWall.x)/2, // USB plug support strut
	(M20.y + USB.y)/2 – ShellRadius,
	-M20.z/2] + USBOffset)
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i(USB.x + ShellWall.x – 2ShellRadius)/2,
	j(USB.y – 2ShellRadius)/2,
	k(USB.z – 2ShellRadius)/2])
	rotate(0*180/ShellSides) rotate([90,0,90])
	sphere(r=ShellRadius/cos(180/ShellSides),$fn=ShellSides);

	translate([-M20fm/2,0,-ShellOA.z/2 – Interposer.z + Protrusion/2])
	InterposerShape(Embiggen = false);
	}

	render(convexity=4) // remove camera shape from interior
	M20Shape(Knockout = true);

	for (j=[-1,1], k=[-1,1]) // screw bores
	translate([-ShellOA.x,jScrewOC.y/2,kScrewOC.z/2])
	rotate([0,90,0]) rotate(180/ScrewSides)
	PolyCyl(Screw[ID],2*ShellOA.x,ScrewSides);

	translate([ShellOA.x/2 – ThreadThick + Protrusion/2,0,-5]) // recess for legend
	cube([EmbossDepth,ShellOA.y – 12,7],center=true);

	translate([0,(M20.y + 1.5*SDCard.z)/2 + ThreadWidth,-M20.z/2 + SDOffset.z])
	resize([M20.x,0,0])
	sphere(d=1.5*SDCard.z,$fn=24);

	}

	translate([ShellOA.x/2 – DebossHeight,0,-5])
	rotate([90,0,90])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text="KE4ZNU",size=5,spacing=1.20,font="Arial:style:Bold",halign="center",valign="center");


	// Totally ad-hoc support structures

	if (false)
	color(SupportColor) {
	for (j=[-1,1], k=[0,1])
	translate([-ShellOA.x/2 + Screw[LENGTH],jShellOA.y/2,kShellOA.z])
	rotate([0,90,0])
	SupportScrew(Dia=Screw[OD] + ScrewClear,Length=ShellOA.x – Screw[LENGTH],Num=ScrewSides);
	}
	}

	// Generate support structure for screw boss

	module SupportScrew(Dia,Length,Num = 6) {
	for (a=[0 : 360/Num : 360/2])
	rotate(a)
	translate([0,0,(Length + ThreadThick)/2])
	cube([Dia – 2ThreadWidth,2ThreadWidth,Length – ThreadThick],center=true);
	}

	// Generate interposer block
	// Origin at center bottom surface for E-Z rotation

	module InterposerShape(Embiggen = false) {

	translate([0,0,Interposer.z/2])
	if (Embiggen) {
	minkowski() {
	cube(Interposer,center=true);
	cube(HoleWindage,center=true);
	}
	}
	else
	cube(Interposer + [-Protrusion,0,Protrusion],center=true); // avoid slivers, merge with shell
	}

	// Cut shell sections for printing
	// "Front" = lens end, toward +X direction
	// origin centered on M20.xyz and ShellOA.xyz

	module ShellSection(Section="Front") {

	if (Section == "Front") // include front curve
	intersection() {
	Shell();
	translate([ShellOA.x – (M20fm + ShellWall.x),0,0])
	cube([ShellOA.x,2ShellOA.y,2ShellOA.z],center=true);
	}
	else if (Section == "Center") // exclude front curve for E-Z printing
	intersection() {
	Shell();
	translate([-M20fm/2,0,0])
	cube([M20.x – M20fm,2ShellOA.y,2ShellOA.z],center=true);
	}
	else if (Section == "Back") // flush with LCD on rear face
	intersection() {
	Shell();
	translate([-ShellOA.x + (ShellWall.x),0,0])
	cube([ShellOA.x,2ShellOA.y,2ShellOA.z],center=true);
	}

	}

	//—–
	// Clamp
	// Grips seat frame rail
	// Uses shell rounding values for tidiness
	// Adjust MountScrew[LENGTH] to put head more-or-less flush with clamp arch

	RailOD = 20.0; // slightly elliptical in bent section
	RailSides = 234;

	ClampOA = [60.0,40.0,ClampScrew[LENGTH]]; // set clamp size to avoid weird screw spacing
	echo(str("Clamp OA: ",ClampOA));

	ClampOffset = 0.0; // raise clamp to allow more room for mount

	ClampTop = ClampOA.z/2 + ClampOffset;
	InsertCap = 6*ThreadThick; // fill layers atop inserts

	Kerf = 2.0;

	module Clamp(Support = false) {

	RibThick = 2*ThreadWidth;
	NumRibs = IntegerMultiple(ceil(ClampOA.y / 4.0),2); // space ribs roughly 4 mm apart
	RibSpace = ClampOA.y / NumRibs;
	echo(str("Ribs: ",NumRibs," spaced: ",RibSpace));

	ClampScrewOC = IntegerMultiple(ClampOA.x – ClampScrew[OD] – 10*ThreadWidth,1.0);
	echo(str("ClampScrew OC: ",ClampScrewOC));

	difference() {
	hull()
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i(ClampOA.x – 2ShellRadius)/2,
	j(ClampOA.y – 2ShellRadius)/2,
	k(ClampOA.z – 2ShellRadius)/2 + ClampOffset])
	sphere(r=ShellRadius/cos(180/ShellSides),$fn=ShellSides);

	cube([2ClampOA.x,2ClampOA.y,Kerf],center=true); // split across middle

	rotate([90,0,0]) // seat rail
	cylinder(d=RailOD,h=2*ClampOA.y,$fn=RailSides,center=true);

	for (i=[-1,1]) // clamp inserts
	translate([i*ClampScrewOC/2,0,0])
	rotate(180/6)
	PolyCyl(ClampInsert[OD],ClampTop – InsertCap,6);

	for (i=[-1,1]) // clamp screw clearance
	translate([i*ClampScrewOC/2,0,-(ClampOA.z/2 – ClampOffset) – InsertCap])
	rotate(180/6)
	PolyCyl(ClampScrew[ID],ClampOA.z,6);

	translate([0,0,ClampTop + 0.7*Interposer.z]) // mounting bolt hole
	rotate(LookAngle)
	translate([0,0,ShellOA.z/2]) {
	M20Shape(Knockout = true);
	translate([0,0,-ShellOA.z/2 – Interposer.z])
	InterposerShape(Embiggen = true);
	}

	translate([ClampOA.x/2 – (EmbossDepth – Protrusion)/2, // recess for LookAngle.z
	0,
	ClampOA.z/4 + ClampOffset])
	cube([EmbossDepth,17,8],center=true);

	translate([0.3*ClampOA.x, // recess for LookAngle.z
	-(ClampOA.y/2 – (EmbossDepth – Protrusion)/2),
	ClampOA.z/4 + ClampOffset])
	cube([10,EmbossDepth,8],center=true);

	translate([0,0,-ClampOA.z/2 + (EmbossDepth – Protrusion)/2]) // recess bottom legend
	cube([35,10,EmbossDepth],center=true);
	}

	translate([ClampOA.x/2 – DebossHeight,0,ClampOA.z/4 + ClampOffset]) // LookAngle.z legend
	rotate([90,0,90])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text=str(LookAngle.z),size=6,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");

	translate([0.3*ClampOA.x,-ClampOA.y/2 + DebossHeight + Protrusion/2,ClampOA.z/4 + ClampOffset]) // LookAngle.y legend
	rotate([90,0,00])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text=str(LookAngle.y),size=6,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");

	translate([0,0,-ClampOA.z/2])
	linear_extrude(height=DebossHeight,convexity=20)
	mirror([0,1,0])
	text(text="KE4ZNU",size=5,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");


	if (Support) {
	difference() {
	color(SupportColor)
	union() {
	for (j=[-NumRibs/2:NumRibs/2])
	translate([0,j*RibSpace,0])
	rotate([90,0,0])
	cylinder(d=RailOD – 2ThreadThick,h=RibThick,$fn=23*4,center=true);
	cube([RailOD – 4ThreadWidth,NumRibsRibSpace,Kerf + 2*ThreadThick],center=true);
	}
	cube([2ClampOA.x,2ClampOA.y,Kerf],center=true); // split across middle
	}
	}

	}


	//—–
	// Battery
	// Based on Anker PowerCore, simplified shapes
	// Includes port & button punchouts

	Battery = [97.5,80.0,22.5]; // X=length, Y includes rounded edges, Z = Y dia

	module BatteryShape() {

	USB = [Projection,38,10]; // clearance around USB output ports
	USBOffset = [0,25.5,0]; // from -Y edge to center of USB block

	ChargeBtn = [11.0 + 5.0,10,5.0 + 5.0]; // charge level check button, enlarged
	Btnc = ChargeBtn.z; // figure button recess into battery curve
	Btnr = Battery.z/2;
	Btnm = Btnr – sqrt(pow(Btnr,2) – pow(Btnc,2)/4);
	ChargeBtnOffset = [17.0,0,0]; // from +X edge to center, centered on Z

	BatterySides = 234;

	hull()
	for (j=[-1,1])
	translate([0,j*(Battery.y – Battery.z)/2,0])
	rotate([0,90,0])
	cylinder(d=Battery.z,h=Battery.x,$fn=BatterySides,center=true);
	translate([(Battery.x + USB.x)/2 – Protrusion,-Battery.y/2 + USBOffset.y,0])
	cube(USB,center=true);
	translate([Battery.x/2 – ChargeBtnOffset.x,Battery.y/2 + ChargeBtn.y/2 – 2*Btnm,0])
	cube(ChargeBtn,center=true);
	}

	//—–
	// Battery cradle

	RackWidth = 89.0; // flat width between rack rails

	CradleWall = [4.0,4.0,3.0]; // wall thickness
	CradleRadius = 2.0; // corner rounding

	CradlePad = 0.5; // cushion around battery
	BatteryBase = CradleWall.z + CradlePad; // actual bottom surface of battery

	CradleOA = [Battery.x + 2*CradleWall.x,
	min((Battery.y + 2*CradleWall.y),RackWidth),
	BatteryBase + Battery.z/3];
	echo(str("Cradle OA: ",CradleOA));

	module Cradle() {

	difference() {
	hull()
	for (i=[-1,1], j=[-1,1]) { // box with tidy rounded corners
	translate([i*(CradleOA.x/2 – CradleRadius),
	j*(CradleOA.y/2 – CradleRadius),
	1*(CradleOA.z – CradleRadius)])
	sphere(r=CradleRadius,$fn=6);
	translate([i*(CradleOA.x/2 – CradleRadius),
	j*(CradleOA.y/2 – CradleRadius),
	0*(CradleOA.z/2 – CradleRadius)])
	cylinder(r=CradleRadius,h=CradleOA.z/2,$fn=6);
	}

	translate([0,0,Battery.z/2 + BatteryBase]) // minus the battery
	minkowski(convexity=3) { // … slightly embiggened
	BatteryShape();
	cube(2*CradlePad,center=true);
	}

	if (false) // reveal insets for debug
	translate([0,0,-Protrusion])
	cube(CradleOA + [0,0,CradleOA.z],center=false);

	translate([0,0,CradleWall.z – ThreadThick + Protrusion/2]) // recess top legend
	cube([55,20,EmbossDepth],center=true);
	translate([0,0,(EmbossDepth – Protrusion)/2]) // recess bottom legend
	cube([70,15,EmbossDepth],center=true);
	}

	translate([0,4.0,CradleWall.z – DebossHeight – Protrusion])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text="PowerCore",size=6,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");

	translate([0,-4.0,CradleWall.z – DebossHeight – Protrusion])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text="13000",size=6,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");

	linear_extrude(height=DebossHeight,convexity=20)
	mirror([0,1,0])
	text(text="KE4ZNU",size=10,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");


	}


	//—–
	// Build things

	// Layouts for design & tweaking

	if (Layout == "Show")

	if (Part == "Battery")
	BatteryShape();

	else if (Part == "Buttons")
	Buttons();

	else if (Part == "Interposer")
	InterposerShape(Embiggen = false);

	else if (Part == "Shell")
	Shell();

	else if (Part == "M20")
	M20Shape(Knockout = false);

	else if (Part == "ShellSections") {
	translate([ShellOA.x,0,0])
	ShellSection(Section="Front");
	translate([0,0,0])
	ShellSection(Section="Center");
	translate([-ShellOA.x,0,0])
	ShellSection(Section="Back");
	}

	else if (Part == "Clamp") {
	Clamp(Support = false);
	color(FadeColor,FadeAlpha)
	rotate([90,0,0])
	cylinder(d=RailOD,h=2*ClampOA.y,$fn=RailSides,center=true);
	}

	else if (Part == "Cradle") {
	Cradle();
	translate([0,0,Battery.z/2 + CradleWall.z])
	color(FadeColor,FadeAlpha)
	BatteryShape();
	}

	// Build layouts for top-level parts

	if (Layout == "Build")

	if (Part == "Cradle")
	Cradle();

	else if (Part == "Clamp") {
	translate([0,0.7*ClampOA.y,0])
	difference() {
	translate([0,0,-Kerf/2])
	Clamp(Support = true);
	translate([0,0,-ClampOA.z])
	cube(2*ClampOA,center=true);
	}
	translate([0,-0.7*ClampOA.y,-0])
	difference() {
	translate([0,0,-Kerf/2])
	rotate([0,180,0])
	Clamp(Support = true);
	translate([0,0,-ClampOA.z])
	cube(2*ClampOA,center=true);
	}
	}

	else if (Part == "Shell") {
	translate([0,-1.2*ShellOA.y,ShellOA.x/2])
	rotate([0,90,180])
	ShellSection(Section="Front");
	translate([0,0,M20.x/2])
	rotate([0,-90,0])
	ShellSection(Section="Center");
	translate([0,1.4*ShellOA.y,ShellOA.x/2])
	rotate([0,-90,180])
	ShellSection(Section="Back");
	}

	// Ad-hoc arrangement to see how it all goes together

	if (Layout == "Fit") {
	rotate(180) {
	Cradle();
	translate([0,0,Battery.z/2 + CradleWall.z])
	color(FadeColor,FadeAlpha)
	BatteryShape();
	}
	translate([0,-100,0]) {
	Clamp();
	color(FadeColor,FadeAlpha)
	rotate([90,0,0])
	cylinder(d=RailOD,h=2*ClampOA.y,$fn=RailSides,center=true);
	}

	translate([0,-100,(ClampOA.z + ShellOA.z)/2 + Interposer.z])
	translate([0,0,-ShellOA.z/2 + Interposer.z])
	rotate(LookAngle)
	translate([0,0,ShellOA.z/2]) {
	Shell();
	color(FadeColor,FadeAlpha)
	M20Shape(Knockout = false);
	}
	}

view raw SJCAM M20 Mount.scad hosted with ❤ by GitHub

2019-02-20

NP-BX1 Lithium Batteries: DOT-01

A quartet of DOT01 NP-BX1 batteries arrived:

Dot01 NP-BX1 – new 2019-02

The dotted lines show the results from late 2015 for a pair of then-new Wasabi NP-BX1 batteries, so the DOT-01 batteries look about the same. The F battery barely lasted to the halfway point of our most recent bike ride and the G battery now resides in the blinky-and-glowy pile.

I’d be unsurprised to discover all the myraid “different” NP-BX1 batteries all come from the same factory. Unlike the Wasabi batteries, these lack date codes, which seems like an extra-cost option you don’t get on the low end.

2019-02-18
Dutchess Rail Trail: Maloney Rd Drive-In Entrance

Perhaps they should just saw off the bollard in the middle of the entrance and be done with it:

Maloney Trailhead – tire tracks 2018-12-15

Some backstory may be of interest.

2018-12-29
Tour Easy Front Fender: Redux

The front fender on Mary’s bike snapped loose while we were on our way for groceries, but my repair kit ~~now~~ once again includes a few feet of duct tape and we continued the mission:

Tour Easy front fender – duct tape FTW

The final fracture seems to be just the little gray section amid the older fractures, so the Planet Bike clip was hanging on by a thread:

Tour Easy front fender – broken clip

Our bikes being equipped as alike as I can make them, another copy of the bracket I used on my bike sufficed:

Tour Easy front fender – new bracket

Stipulated: duct tape is déclassé, but it works better than anything else I’ve tried.

2018-12-24
Dutchess Rail Trail: Maloney Rd Trailhead Ruts

It seems the DCW&WA SUV makes regular trips through the “No Motor Vehicles” bike access:

Maloney Rd Trailhead – 2018-11-07

If it’s not them, then it’s somebody following their example.

Just because you can do something, doesn’t mean you should … but, of course, the ordinary rules apply only to little people, not public servants.

Someone in the bike advocacy apparat once told me I’m the most cynical, bitter person they’d ever met, at least on the subject of getting along with public servants. As I see it, I came by my attitude honestly.

2018-12-10
Badger Propel Air Fittings: DIY Rubber Washers

Unlike ordinary bike tubes, Michelin ProTek tubes have a square-ish cross section:

Michelin Protek Max Tube – carton

So, having a defunct Michelin ProTek tube in hand, I cut, cleaned, and dissected a few inches, then punched out a set of (flat!) washers for the Badger Propel air fittings:

Badger 260 Propel fitting seals – inner-tube version

As with the cork version, they fit fine:

Badger Propel fitting – DIY rubber seal

The picture is slightly fuzzy, because zooming a Pixel photo doesn’t magically create any new mmmm pixels.

I tested the washer with 45 psi air (the recommended maximum) and it holds the pressure fine. Better than a fouled ProTek valve, anyway.

Flushed with success, I preemptively replaced both OEM cork washers, an action which will surely come back to haunt me.

2018-11-25