Month: September 2021

Bondhus Wrench Replacement

The Bondhus Lifetime Guarantee works, as a replacement wrench just arrived:

Bondhus hex wrenches – 7-64 ball end – replacement

A close look at the aligned tips suggests the defective wrench blank was mis-chucked in the machine cutting the ball end:

Bondhus hex wrenches – 7-64 ball end – replacement – detail

All’s well that ends well: thank you, Bondhus!

2021-09-30
Micro-Mark Bandsaw: Acetal Upper Blade Guide

There being nothing like a good new problem to take one’s mind off all one’s old problems:

Micro-Mark Bandsaw – acetal upper blade guide installed

It’s basically the same as the lower blade guide, except coming from a stick of 5/8 inch acetal. A scant 6 mm stem goes into the vertical square rod, with a flat matching the setscrew coming up from the bottom to hold it in proper alignment.

I came within a heartbeat of cutting the slot parallel to the flat.

It worked OK while cutting a chunk of stout aluminum tube: so far, so good!

The impressive chunk of hardware is the OEM blade guide, with the brass tube for coolant flow all over the bearings. It’s mostly intended for use with the diamond blade, so I’ll swap it back in when I finally get around to cutting some slate for base plates.

2021-09-29
Tour Easy Rear Running Light: Current Waveforms

There’s just enough slack in the LED wiring to clip a Tek current probe in there:

Tour Easy Rear Running Light – regulator wiring

Which reveals the LED current waveform:

Red LED – LED current – 100 mA-div

The LED is on continuously, except for the two 75 ms Morse code dits in the upper trace.

The lower trace shows the current ramping up at the end of the first dit, from zero to 400 mA in 1.5 ms.

Clamping the probe around the 6.3 V power supply lead:

Red LED – power supply – 100 mA-div

The supply current includes maybe 20 mA for the Arduino running the Morse code program and the current ramps up from there to about 250 mA when the LED is on.

The LED drops 2.6 V at 400 mA, so it dissipates a smidge over 1 W. The 2.0 Ω current sense resistor (3.3 Ω in parallel with 5.1 Ω) dissipates 800 mV × 400 mA = 320 mW.

The dissipation from the Bafang headlight output, including the Arduino, is 1.6 W.

The running light ticks along at the hot side of comfortably warm on the Electronics Workbench and runs barely warm in free air out on the bike, so I’ll define it to be Good Enough™.

2021-09-28
Tour Easy Rear Running Light: First Light!
The rear running light definitely has an industrial look:

Tour Easy Rear Running Light – installed

The front of the light has plenty of clearance from the seat mesh:

Tour Easy Rear Running Light – installed side view

Out on the road, the 1 W LED appears about as bright as automotive running lights:

Tour Easy Rear Running Light – tunnel

The blink pattern makes it perfectly visible in sunlight, although I’d prefer somewhat larger optics:

Tour Easy Rear Running Light – sunlight

In shaded conditions, it’s downright conspicuous:

Tour Easy Rear Running Light – shade

At any reasonable distance, the 10° beam covers much of the road behind the bike:

Tour Easy Rear Running Light – distant

You may not know what the occulting red light represents, but something ahead is worthy of your attention.

The Arduino source code producing the two dits:
```
// Tour Easy Running Light
// Ed Nisley - KE4ZNU
// September 2021

#include <morse.h>

#define PIN_OUTPUT  13

// second param: true = active low output
LEDMorseSender Morser(PIN_OUTPUT,true,(float)10.0);

void setup()
{
    Morser.setup();

    Morser.setMessage(String("qst de ke4znu "));
    Morser.sendBlocking();

//    Morser.setWPM((float)3.0);
    Morser.setSpeed(75);
    Morser.setMessage(String("i   "));
}

void loop()
{
    if (!Morser.continueSending())
        Morser.startSending();

}
```
Looks good to me, anyhow.
2021-09-27
Beaver Lodge II

The beaver family living in their pond along the Dutchess Rail Trail near Titusville Rd is doing so well they’ve erected a second lodge:

Second Beaver Lodge – near Titusville Rd – 2021-09-23

It’s 500 feet (-ish) upstream from the first lodge and seems somewhat smaller, so perhaps it’s for the kids.

2021-09-26
Why LED Lamps Fail

Spotted over a fast food emporium’s parking lot:

Disemboweled parking lot light

It’s hard to be sure, but I think there’s a paper wasp nest around the bundle of wires just above the transformer / ballast / whatever. Perhaps the repair tech departed with the job unfinished?

As with traffic signals, flashlights, and automotive lighting, the LEDs surely work long after the driver circuitry has given up.

2021-09-25

Tour Easy Rear Running Light: Circuit Support Plate

Building the circuit support plate for the amber front running light was entirely too fiddly:

1 W LED Running Light - baseplate dry assembly — 1 W LED Running Light – baseplate dry assembly

This was definitely easier:

Running Light Circuit Plate - solid model — Running Light Circuit Plate – solid model

Two pins fit in the small holes to align it with the LED heatsink, with an M3 stud and brass insert holding it in place:

Tour Easy Rear Running Light - circuit plate attachment — Tour Easy Rear Running Light – circuit plate attachment

The rectangular hole around the insert let me glop urethane adhesive over it to lock it into the plate, with more goop on the screw and pins to unify heatsink and plate.

The LED wires now emerge from the heatsink on the same side of the plate, simplifying the connections to the MP1584 regulator and current-sense resistor:

Tour Easy Rear Running Light - regulator wiring — Tour Easy Rear Running Light – regulator wiring

The paralleled 5.1 Ω and 3.3 Ω resistors form a 2.0 Ω resistor setting the LED current to 400 mA = 1 W at 2.6 V forward drop. They’re 1 W resistors dissipating a total of 320 mW and get barely warm.

The resistors and wires are stuck in place with clear adhesive, so things shouldn’t rattle around too much.

The OpenSCAD source code as a GitHub Gist:

	// Circuit plate for Tour Easy running lights
	// Ed Nisley – KE4ZNU – 2021-09

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

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

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

	inch = 25.4;

	//———————-
	// Dimensions
	// Light case along X axis

	LightID = 23.0;

	WallThick = 2.0;

	Screw = [3.0,6.8,4.0]; // M3 OD=washer, length=nut + washers
	Insert = [3.0,4.2,8.0]; // splined brass insert, minus splines

	InsertOffset = 10.0; // insert from heatsink end

	PinOD = 1.6; // alignment pins
	PinOC = 14.0;
	PinDepth = 5.0;

	Plate = [50.0,LightID,Insert[OD] + 4*ThreadThick]; // overall plate size

	WirePort = [10.0,3.0,2*Plate.z];

	NumSides = 234;

	//———————-
	// Useful routines

	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);
	}

	// Circuit plate

	module Plate() {

	difference() {
	intersection() {
	cube(Plate,center=true);
	rotate([0,90,0])
	cylinder(d=LightID,h=2*Plate.x,$fn=NumSides,center=true);
	}

	rotate([0,90,0]) rotate(180/6)
	translate([0,0,-Plate.x])
	PolyCyl(Screw[ID],2*Plate.x,6);

	rotate([0,90,0]) rotate(180/6)
	translate([0,0,-Plate.x/2 – Protrusion])
	PolyCyl(Insert[OD],Insert[LENGTH] + InsertOffset + Protrusion,6);

	translate([-Plate.x/2 + InsertOffset + Insert[LENGTH]/2,0,Plate.z/2])
	cube([Insert[LENGTH],Insert[OD],Plate.z],center=true);

	for (j=[-1,1])
	translate([-Plate.x/2,j*PinOC/2,0])
	rotate([0,90,0]) rotate(180/6)
	translate([0,0,-PinDepth])
	PolyCyl(PinOD,2*PinDepth,6);

	for (j=[-1,1])
	translate([0,j*(Plate.y/2 – WirePort.y/2),0])
	cube(WirePort,center=true);


	}

	}

	//- Build it

	Plate();

view raw Running Light Circuit Plate.scad hosted with ❤ by GitHub

2021-09-24

Month: September 2021

Bondhus Wrench Replacement

Micro-Mark Bandsaw: Acetal Upper Blade Guide

Tour Easy Rear Running Light: Current Waveforms

Tour Easy Rear Running Light: First Light!

Beaver Lodge II

Why LED Lamps Fail

Tour Easy Rear Running Light: Circuit Support Plate