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.

Category: Recumbent Bicycling

Cruisin’ the streets

Sting-Kill: Everyday Carry Tube

One of Mary’s gardening cronies suggested Sting-Kill might reduce her dramatic swelling [^1] after a bee / wasp / insect sting. Because it must be applied immediately after the sting, the swab must be on hand in the garden or on a bike ride, but the glass vial inside seem entirely too fragile to survive amid the usual clutter of a purse / pocketbook / belt pack / bike pack.

Well, I can fix that:

Pill tube – PETG default

It’s a KeyChain Pill Tube from Printables, enlarged 20% in the XY plane to fit the Sting-Kill swab, with the white applicator end fitting neatly into the domed screw-on lid for a bit of cushioning.

The solid model looks about like you’d expect:

Pill Tube – slicer preview

Despite that preview, I printed it with a brim. PETG sticks tenaciously to the Textured PEI steel sheet and a brim wasn’t really needed; just pop the parts off the platform when cool.

Somewhat to my astonishment, the threads screwed together easily, smoothed out after a few on-and-off cycles, and it’s ready for a moment we both hope will never occur.

[^1] Mary did tote an EpiPen back in the day, but a few near misses indicated she’s no longer quite as sensitized. She does swell up something powerful and we’re hoping immediately applying a Sting-Kill will help knock it down.

2024-09-02
Anker A1215 PowerCore 13000 Power Banks: Five Years

After five years of powering the action cameras on our Tour Easy recumbents, the pair of Anker A1215 PowerCore 13000 USB power banks have about 8 A·hr of capacity with a 2 A load after a full charge:

Anker PowerCore 13000 – 20204-07-26

It seems I did not test them on arrival, so I have no idea what their original capacity might have been, but I’m certain it wasn’t the 13 A·hr implied by their name.

The sawtooth voltage output looks like the internal controller picks a constant boost (or buck) ratio based on the battery voltage, then adjusts it when the output voltage falls below the lower limit. You can imagine it desperately boosting the ratio as the battery voltage falls off a cliff near the end of the curve.

I have no idea why the two packs behave so differently, although the voltages are certainly within ordinary USB limits.

They’ll continue powering the camera on my bike for a while, after which I’m sure they’ll come in handy for something …

2024-08-06

Tour Easy: Anker 20K V2 USB Power Bank

After five years, it’s time to replace the Anker 13000 mA·hr USB power banks / chargers I used with the M20 cameras and then the C100 cameras:

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

The Anker 325 20K V2 power bank is considerably chunkier, as befits its 20,000 mA·hr cell capacity (although the fine print says 12,500 mA·hr output):

Anker 20K V2 Power Bank - installed — Anker 20K V2 Power Bank – installed

The white tape stripe on the top marks the USB port on the end to reduce the fumbling involved in an out-of-sight socket. There’s also a USB-C port on that end for both charging the pack and powering other devices.

The new mounting cradle descends directly from the 13000 cradle:

Anker 325 20KV2 Power Bank - slicer preview — Anker 325 20KV2 Power Bank – slicer preview

The model includes a projection of the battery on the XY plane for export to an SVG file suitable for laser-cutting an EVA foam pad to cushion the bumps.

The OpenSCAD source code as a GitHub Gist:

	// Anker PowerCore 325 20K V2 Power Bank
	// Ed Nisley – KE4ZNU
	// 2024-07

	/* [Layout Options] */

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

	Part = "Cradle"; // [Cradle,Battery,Pad]


	/* [Extrusion Parameters] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions

	/* [Hidden] */

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

	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

	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);
	}


	//—–
	// Battery
	// Based on Anker PowerCore 325, simplified shapes
	// Includes port punchouts

	Battery = [162.0+0.5,81.5+0.5,24.0]; // X=length, Y=max, Z=max

	module BatteryShape(Jacks = true) {

	USB = [[Projection,20,12],[Projection,18,10]]; // clearance around USB output jacks
	USBOffset = [[0,20.0,0],[0,62.5,0]]; // from -Y edge to center of jack, Z centered

	BatteryRad = 7.0; // corner rounding radius
	BatterySides = 234;

	hull()
	for (i=[-1,1], j=[-1,1])
	translate([i*(Battery.x/2 – BatteryRad),
	j*(Battery.y/2 – BatteryRad),
	0])
	cylinder(r=BatteryRad,h=Battery.z,$fn=BatterySides,center=true);
	if (Jacks)
	for (i=[0,len(USB)-1])
	translate([(Battery.x + USB[i].x)/2 – Protrusion,-Battery.y/2 + USBOffset[i].y,0])
	cube(USB[i],center=true);
	}

	//—–
	// Battery cradle

	RackWidth = 90.0; // flat width between rack rails

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

	CradlePad = 1.0; // cushion on battery bottom
	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/2];
	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);
	}

	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="20K V2",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 == "Cradle") {
	Cradle();
	translate([0,0,Battery.z/2 + CradleWall.z])
	color(FadeColor,FadeAlpha)
	BatteryShape();
	}

	else if (Part == "Pad")
	linear_extrude(height=CradlePad)
	projection(cut=true)
	BatteryShape(Jacks = false);



	// Build layouts for top-level parts

	if (Layout == "Build") {

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

	if (Part == "Pad")
	projection(cut=true)
	BatteryShape(Jacks = false);

	}

view raw Anker 325 20KV2 Power Bank.scad hosted with ❤ by GitHub

2024-08-05

Tour Easy: PTT Button Replacement

After five years and one cleaning, the PTT button on Mary’s Tour Easy became increasingly intermittent, both failing to activate solidly and sticking closed (there being nothing quite like a hot mic during a good hill climb), so it’s time for an autopsy:

Failed PTT Switch – as extracted

The snap dome is much more scarred at the central contact:

Failed PTT Switch – snap plate

That might be a gold flash coating, but it’s pretty well worn away where it hits the central contact:

Failed PTT Switch – center contact

Those scratches surely happened during the previous cleaning pass, as I don’t see any way for the dome to create them.

The corner contact also shows some scuffs, along with a scar where the dome corner pivots:

Failed PTT Switch – edge contact

All in all, though, it worked quite well.

The replacement switch, also intended for indoor use on a keypad or some such device, pivots around the front edge and may be easier for her fingertip to activate:

New PTT Switch – installed

Hot melt glue seems vastly underrated for how wonderful a structural material it is.

If this one lasts five years, I’ll be perfectly happy.

2024-07-31
Rail Trail Brush Clearing

Having an aversion to getting slapped in the face by Blackthorn branches overhanging the Dutchess Rail Trail, I generally give up waiting for anybody else to do the job:

Brush clearing B – 2024-07-14

They’re not all Blackthorn (Prunus spinosa), but Ailanthus altissima grows like a weed around here and requires heavy cutback:

Brush clearing C – 2024-07-14

It’s not just small branches:

Brush clearing A – 2024-07-14

Apparently, there was no law against that …

Brush clearing E – 2024-07-14

A recent storm dropped many trees across the trail and the maintenance folks deploy bigger saws than I can carry:

Brush clearing D – 2024-07-14

Three months after we were told they had ordered replacement tiles, I’m beginning to think I must buy some on Amazon and do this job myself, too:

Overocker ADA – continued disintegration – 2024-07-21

Maybe it’ll get done when the weather cools …

2024-07-30
Tour Easy Running Lights: Updated Lights
With the new battery mount & buck converter box installed on Mary’s bike, I updated the running light circuitry to match the ones on my bike. The original wiring just supplied 6.3 V from the headlight circuit, but now the four wire ribbon cable from the electronics box carries 6.3 VDC from the buck converter and a 6 VDC signal going high when the DPC-18 display’s “headlight” output goes active. The latter goes into an optoisolator pulling down Pin 2, telling the running light to stay on continuously.

The optoisolator sits next to the Arduino Nano’s Reset button:

Tour Easy Running Light – unified light top

The black wire barely visible below the optoisolator jumpers Pin 3 to ground, telling the firmware that this is the front running light.

The black & white wires from the top of the optoisolator connect directly to the ribbon cable entering on the other side:

Tour Easy Running Light – unified light bottom

The gray wrap of clear silicone tape mummifies the wire-to-wire soldered connectors.

The firmware now pays attention to the jumper input, so I need only one source file for both front and rear lights:
```
    if (digitalRead(PIN_POSITION) == HIGH) {
        Blinks = String("i e  ");             // rear = occulting
        Polarity = true;
    }
    else {
        Blinks = String("n e  ");             // front = blinking
        Polarity = false;
    }
```
It just doesn’t get much easier than that!

The Arduino source code as a GitHub Gist:
2024-07-05
M5 Tee Nut: Test To Destruction

The mounting block under the electronics box for the new UPP battery has a recess for an M5 tee nut:

UPP Battery Mount – Block 5 Show View

As with the Terry frame mounts, I glued the modified tee nut in place with JB Plastic Bonder urethane adhesive, did a test fit on the bike, discovered the whole affair had to sit about 10 mm forward, put the new frame measurement into the OpenSCAD code, and ran off a new block.

Which gave me the opportunity to perch the old block atop the bench vise with the tee nut aimed downward between the open jaws, run an M5 bolt into the nut, and give it a good thwack with a hammer:

UPP Battery Mount – M5 insert adhesive test

Although the urethane adhesive didn’t bond uniformly across the tee nut, it had enough grip to tear the PETG layers apart and pull chunks out of the block.

As with the tee nuts on the Terry bike, this one will be loaded to pull into the block, so it will never endure any force tending to pull things apart, but it’s nice to know how well JB Plastic Bonder works.

I chiseled the PETG and adhesive debris off the tee nut, cleaned it up, slathered more Bonder on the new block, and squished the nut in place. After I get the electronics box sorted out, the whole affair will never come apart again!

2024-06-20