Category: Recumbent Bicycling

Cruisin’ the streets

Machine Shop, Recumbent Bicycling, Software

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 = 2*3*4;
//----------------------
// 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
Machine Shop, Recumbent Bicycling

Tour Easy Rear Running Light: LED Lens Assembly

Having discovered the need for careful alignment of the LED PCB with the lens, I paid more attention to detail this time around.

The LEDs arrive soldered to PCBs atop aluminum star heat spreaders, but the one I picked out of the bag looked slightly misaligned. Unsoldering it showed a smear of solder paste had melted across the central pad:

1 W LED PCB - errant solder
1 W LED PCB – errant solder

The LED has a die contact slug on the bottom which, I suppose, could be directly soldered to the spreader. For my simple needs, removing the errant solder, plunking the LED atop a layer of heatsink compound, and resoldering the leads should suffice:

1 W LED PCB - wire layout
1 W LED PCB – wire layout

The LED holder has a pair of slots aligning it with the LED leads on the PCB. The base of the holder sits flush against the PCB, so the wires must attach directly to the LED pads.

I ran the wires for the amber light through holes close to the pads:

1 W LED Running Light - heatsink fit
1 W LED Running Light – heatsink fit

Which required chewing two passages in the base of the holder:

1 W LED Running Light - wiring
1 W LED Running Light – wiring

It turns out the 5° and 10° lenses are strongly conical and leave plenty of room around the LED to run a wire around the inside of the holder, so I drilled a pair of holes to put both wires on the same side of the circuit plate:

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

The holder required minor surgery to let the wire double back on itself over the LED pad:

1 W LED Holder - wire passage
1 W LED Holder – wire passage

The wires thread through two holes drilled in the plastic holder:

Tour Easy Rear Running Light - clamped LED assembly
Tour Easy Rear Running Light – clamped LED assembly

More urethane adhesive glues the PCB to the LED holder, with the clamp applying pressure to the lens to ensure the lens seats properly around the LED. It turned out that worked well and the light has a nicely rounded beam.

With the optics bonded together, metal-filled JB Weld epoxy attaches the heat spreader to the heatsink with good thermal conductivity:

Tour Easy Rear Running Light - clamped LED heatsink
Tour Easy Rear Running Light – clamped LED heatsink

The LED holder is a slide fit in the heatsink, so the clamps can keep the PCB flat on the bottom of the recess while the epoxy gets a good grip on all parts.

Now it’s just a matter of wiring everything up!

Machine Shop, Recumbent Bicycling

Tour Easy Rear Running Light: LED Heatsink

Because the rear running light will have a higher duty cycle than the front light, I made the (admittedly too small) heatsink slightly longer, with a deeper recess to protect the lens from cargo on the rear rack:

Tour Easy Rear Running Light - boring LED recess
Tour Easy Rear Running Light – boring LED recess

Boring that nice flat bottom is tedious; I must lay in a stock of aluminum tubing to simplify the process.

Drilling the holes went smoothly:

Tour Easy Rear Running Light - drilling LED heatsink
Tour Easy Rear Running Light – drilling LED heatsink

Those two holes fit a pair of pins aligning the circuit plate, with a screw and brass insert holding it to the heatsink. Scuffing a strip across the aluminum might give the urethane adhesive (you can see uncured globs on the pins) a better grip:

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

The screw / insert /pins are glued into the plate to permanently bond it to the heatsink. The screw occupies only half of the insert, with the longer screw from the end cap pulling the whole affair together.

The two holes on the left pass both LED leads to one side of the circuit plate, where they connect to the current regulator and its sense resistor.

Home Ec, Machine Shop, Recumbent Bicycling

Rear Running Light: Too-aggressive Turning

The same lathe fixture and double-sided duct tape trick I used for the amber running light’s end cap should have worked for this one, but only after I re-learned the lesson about taking sissy cuts:

Tour Easy Rear Running Light - end cap fixture - swirled adhesive
Tour Easy Rear Running Light – end cap fixture – swirled adhesive

Yet another snippet of tape and sissy cuts produced a better result:

Tour Easy Rear Running Light - end cap
Tour Easy Rear Running Light – end cap

Protip: when you affix an aluminum disk bandsawed from a scrap of nonstick griddle to a lathe fixture, the adhesive will grip the disk in only one orientation.

Machine Shop, Recumbent Bicycling, Software

Rear Running Light: Tour Easy Seat Clamp

With the amber front running light blinking away, it’s time to replace the decade-old Planet Bike Superflash behind the seat:

Superflash on Tour Easy
Superflash on Tour Easy

The new mount descends directly from the clamps holding the fairing strut on the handlebars and various hose clamps:

Rear Running Light Seat Clamp - solid model
Rear Running Light Seat Clamp – solid model

The central block has two quartets of brass inserts epoxied inside:

Rear Running Light Seat Clamp - sectioned - solid model
Rear Running Light Seat Clamp – sectioned – solid model

That means I can install the light, then mount the whole affair on the bike, without holding everything together while fiddling with overly long screws.

A trial fit with the not-yet-cut-to-length 25.3 (-ish) PVC pipe body tube:

Rear Running Light - Tour Easy seat clamp trial fit
Rear Running Light – Tour Easy seat clamp trial fit

The aluminum plates have the standard used-car finish: nice polish over deep scratches.

Although I’ve been thinking of mounting the light below the seat rail, as shown, it can also sit above the rail.

Mary hauls seedlings and suchlike to the garden in a plastic drawer bungied to the rack, with the SuperFlash serving as an anchor point; this light may need fine tuning for that purpose.

The OpenSCAD source code as a GitHub Gist:

// Rear running light clamp for Tour Easy seat strut
// Ed Nisley - KE4ZNU - 2021-09
Layout = "Show"; // [Show,Build,Block]
Section = true;
/* [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, seat strut along Y, Z=0 at strut centerline
LightOD = 25.4 + HoleWindage;
StrutOD = 5/8 * inch + HoleWindage;
PlateThick = 1/16 * inch;
WallThick = 2.0;
Kerf = ThreadThick;
Screw = [3.0,6.8,4.0]; // M3 OD=washer, length=nut + washers
Insert = [3.0,5.4,8.0 + 1.0]; // splined brass insert
RoundRadius = IntegerMultiple(Screw[OD]/2,0.5); // corner rounding
ScrewOC = [IntegerMultiple(StrutOD + 2*WallThick + Screw[ID],1.0),
IntegerMultiple(LightOD + 2*WallThick + Screw[ID],1.0)];
echo(str("Screw OC: ",ScrewOC));
BlockSize = [ScrewOC.x + Insert[OD] + 2*WallThick,
ScrewOC.y + Insert[OD] + 2*WallThick,
LightOD + StrutOD + 3*WallThick];
echo(str("Block: ",BlockSize));
BaseOffset = -(WallThick + LightOD/2); // block bottom to centerline
StrutOffset = LightOD/2 + WallThick + StrutOD/2; // light centerline to strut centerline
echo(str("Strut screw min: ",IntegerMultiple(PlateThick + WallThick + StrutOD/2 + Insert[LENGTH]/2,1.0)));
echo(str("Light screw min: ",IntegerMultiple(PlateThick + WallThick + LightOD/2 + Insert[LENGTH]/2,1.0)));
NumSides = 2*3*4;
//----------------------
// 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,
$fn=Sides);
}
// Block with light along X axis
module Block() {
difference() {
hull()
for (i=[-1,1], j=[-1,1])
translate([i*(BlockSize.x/2 - RoundRadius),j*(BlockSize.y/2 - RoundRadius),BaseOffset])
cylinder(r=RoundRadius,h=BlockSize.z,$fn=NumSides);
for (i=[-1,1], j=[-1,1])
translate([i*ScrewOC.x/2,j*ScrewOC.y/2,BaseOffset - Protrusion])
rotate(180/8)
PolyCyl(Screw[ID],BlockSize.z + 2*Protrusion,8);
for (i=[-1,1], j=[-1,1])
translate([i*ScrewOC.x/2,j*ScrewOC.y/2,0]) {
translate([0,0,-Protrusion])
rotate(180/8)
PolyCyl(Insert[OD],Insert[LENGTH] + 1*Protrusion,8);
translate([0,0,(StrutOffset - Insert[LENGTH] - Kerf/2 + Protrusion)])
rotate(180/8)
PolyCyl(Insert[OD],Insert[LENGTH] + 1*Protrusion,8);
}
translate([-BlockSize.x,0,0])
rotate([0,90,0])
cylinder(d=LightOD,h=2*BlockSize.x,$fn=NumSides);
translate([0,BlockSize.y,StrutOffset])
rotate([90,0,0])
cylinder(d=StrutOD,h=2*BlockSize.y,$fn=NumSides);
translate([0,0,StrutOffset])
cube([2*BlockSize.x,2*BlockSize.y,Kerf],center=true);
cube([2*BlockSize.x,2*BlockSize.y,Kerf],center=true);
}
}
//- Build it
if (Layout == "Block")
if (Section)
difference() {
Block();
rotate(atan(ScrewOC.y/ScrewOC.x))
translate([0,BlockSize.y,0])
cube(2*BlockSize,center=true);
}
else
Block();
if (Layout == "Show") {
Block();
color("Green",0.25)
translate([-BlockSize.x,0,0])
rotate([0,90,0])
cylinder(d=LightOD,h=2*BlockSize.x,$fn=NumSides);
color("Green",0.25)
translate([0,BlockSize.y,StrutOffset])
rotate([90,0,0])
cylinder(d=StrutOD,h=2*BlockSize.y,$fn=NumSides);
}
if (Layout == "Build") {
translate([-1.2*BlockSize.x,0,-BaseOffset])
difference() {
Block();
translate([0,0,BlockSize.z])
cube(2*BlockSize,center=true);
}
translate([1.2*BlockSize.x,0,StrutOD/2 + WallThick])
difference() {
rotate([180,0,0])
translate([0,0,-StrutOffset])
Block();
translate([0,0,BlockSize.z])
cube(2*BlockSize,center=true);
}
translate([0,0,StrutOffset - Kerf/2])
rotate([180,0,0])
intersection() {
Block();
translate([0,0,StrutOffset/2])
cube([2*BlockSize.x,2*BlockSize.y,StrutOffset],center=true);
}
}
view raw Rear Running Light Seat Clamp.scad hosted with ❤ by GitHub
Oddities, Recumbent Bicycling

Rail Trail: Fallen Tree Clearing

We rolled up to a pair of walkers who had just watched a long-dead tree fall across the Dutchess Rail Trail ahead of them:

Rail Trail - fallen tree - 2021-09-15
Rail Trail – fallen tree – 2021-09-15

Which is why I now carry a fold-out pruning saw in my tool kit:

Rail Trail - fallen tree - cleared - 2021-09-15
Rail Trail – fallen tree – cleared – 2021-09-15

The mowing crew we encountered half a mile ahead had a chainsaw and cleared the remainder.

Stay alert out there!

Although I don’t have a picture, there was a freshly dead bat lying underneath the main trunk. I think it rode the tree down, only to get slapped hard against the gravel beside the trail. I’m sure bats power up faster than I do, but not quite fast enough.

Electronics Workbench, Recumbent Bicycling, Science

Tenergy 18650 Lithium Cells: Four Years of Running Lights

With the amber daytime running light connected to the Bafang’s headlight output and the Anker flashlight on the other side of the fairing getting fewer power-on hours, it’s a good time to see how those four Tenergy lithium 18650 cells are doing:

Tenergy 18650 Protected - 2021-09-09
Tenergy 18650 Protected – 2021-09-09

The overall capacity is down by 10%, with the voltage depressed by 120 mV over most of the curve.

Although I don’t keep daily records, the back of the envelope reveals 150 to 200 hour-long rides per year during the last four years, so call it 700 charging cycles:

Anker LC40 Flashlight - Anodizing fade
Anker LC40 Flashlight – Anodizing fade

High brightness draws 1.5 A and low is 50% duty cycle, so a typical ride requires 750 mA·h = 2.5 W·h. Each cell lives for three or four rides with the LED set to low brightness and the numbers work out close enough.