Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
About a week after First Light, one of the knockoff Neopixels (not a Genuine Adafruit Product) suffered an intermittent failure: it worked fine after being off for an hour or two, but eventually stalled at a fixed color, with all downstream pixels equally dead. Of course, it was the middle package in the string of three, buried in the hub (this is before the failure):
Hard Drive Mood Light – low angle
Spraying circuit cooler on the package brought it back to life for a few minutes, confirming the diagnosis. Reducing the maximum intensity to PWM 32 reduced the average power dissipation enough to let it run for as long as I was willing to let it, although it might not survive a hot summer day.
Not having glued the spacers onto the hub simplified extracting the strip, although warranty repair is always a nuisance. I daubed red Sharpie on the failing LED to avoid losing track of it, then resoldered the LED and capacitor connections to no avail:
Knockoff Neopixel Failure – overview
There’s nothing obviously wrong inside:
Knockoff Neopixel Failure – detail
The fine details of the WS2812B controller produce a horrible Moiré blur with the camera’s low-res image, but you get the general idea.
Most likely, one of those flying wires isn’t quite bonded, but we’ll never know…
An improved version of the 3D printed plastic bits going into the Hard Drive Platter Mood Light:
Hard Drive Mood Light – improved – solid model – Show view
The central pillar now has cutouts behind the Neopixel strips so you (well, I) can solder directly to the larger half-pads on the back, plus a boss on the top for better wire management:
Hard Drive Mood Light – improved – Pillar – solid model
I’m not entirely satisfied with the little slots for the strip edges; the resolution limits of 3D printing call for larger openings, but there’s not much meat around those pins up the edge.
The base becomes much larger to hold the Arduino Pro Mini and gains an optional slot to let the programming cable reach the outside:
Hard Drive Mood Light – improved – Base – solid model
The cap has a boss matching the one atop the pillar:
Hard Drive Mood Light – improved – Cap – solid model
Both the cap & base have center features recessed by two thread thicknesses to let their rims apply a slight clamping force on the platters.
Our Larval Engineer says it really needs an internal battery with maybe four hours of runtime, a charging base station (ideally with inductive power transfer), buttons (or, better, a tilt switch / accelerometer) for mode selection, and perhaps a microphone to synchronize lighting effects with music. To my horror, her co-op job seems to have exposed her to Marketeers…
We do, however, agree that the Cap would look better in lathe-turned brass with a non-tarnish clearcoat.
The OpenSCAD source code:
// Hard Drive Platter Mood Light
// Ed Nisley KE4ZNU November 2015
Layout = "Spacers"; // Build Show Pixel LEDString Platters Pillar Spacers TopCap Base
CablePort = true;
ShowDisks = 2; // number of disks in Show layout
//- Extrusion parameters must match reality!
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleWindage = 0.2;
Protrusion = 0.1; // make holes end cleanly
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
//----------------------
// Dimensions
ID = 0;
OD = 1;
LENGTH = 2;
Platter = [25.0,95.0,1.27]; // hard drive platters - must match actual thickness!
LEDStringCount = 3; // number of LEDs on each strip
LEDStripCount = 4; // number of strips (verify locating pin holes & suchlike)
WireSpace = 1.0; // allowance for wiring along strip ends
Pixel = [13.0, 1000 / 144, 0.6]; // smallest indivisible unit of LED strip
PixelMargin = [1.0, 1.0, 2.0]; // LED and circuitry atop the strip
BeamAngle = 120; // LED viewing angle
BeamShape = [
[0,0],
[Platter[OD]*cos(BeamAngle/2),-Platter[OD]*sin(BeamAngle/2)],
[Platter[OD]*cos(BeamAngle/2), Platter[OD]*sin(BeamAngle/2)]
];
PillarSides = 12*4;
PillarCore = Platter[ID] - 2*(Pixel[2] + PixelMargin[2] + 2.0); // LED channel distance across pillar centerline
PillarLength = LEDStringCount*Pixel[1] + Platter[LENGTH];
echo(str("Pillar core size: ",PillarCore));
echo(str(" ... length:"),PillarLength);
PCB = [34.5,17.5,1.6]; // Arduino Pro Mini (or whatever) PCB size
PCBClearTop = 5.0;
PCBClearBot = 5.0;
PCBHeight = PCB[2] + PCBClearBot + PCBClearTop;
PCBRadius = sqrt(pow(Platter[ID]/2 + PCB[1],2) + pow(PCB[0]/2,2));
echo(str("PCB Corner radius: ",PCBRadius));
CoaxConn = [7.8,11.2,5.0]; // power connector
Cap = [Platter[ID] + 4.0,Platter[ID] + 4.0 + 10*2*ThreadWidth,2*WireSpace + 6*ThreadThick]; // cap over top of pillar
CapSides = 8*4;
BaseClearHeight = max(PCBHeight,CoaxConn[OD]);
Base = [2.0 + 2*PCBRadius,2.0 + 2*PCBRadius + CoaxConn[LENGTH],BaseClearHeight + 6*ThreadThick];
BaseSides = 8*4;
Screw = [1.5,2.0,20.0]; // screws used to secure cap & pillar
Spacer = [Platter[ID],(Platter[ID] + 2*8),(Pixel[1] - Platter[LENGTH])];
echo(str("Spacer OD: ",Spacer[OD]));
echo(str(" ... thick:",Spacer[LENGTH]));
LEDStripProfile = [
[0,0],
[Pixel[0]/2,0],
[Pixel[0]/2,Pixel[2]],
[(Pixel[0]/2 - PixelMargin[0]),Pixel[2]],
[(Pixel[0]/2 - PixelMargin[0]),(Pixel[2] + PixelMargin[2])],
[-(Pixel[0]/2 - PixelMargin[0]),(Pixel[2] + PixelMargin[2])],
[-(Pixel[0]/2 - PixelMargin[0]),Pixel[2]],
[-Pixel[0]/2,Pixel[2]],
[-Pixel[0]/2,0]
];
//----------------------
// 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,
$fn=Sides);
}
//- Locating pin hole with glue recess
// Default length is two pin diameters on each side of the split
PinOD = 1.70;
module LocatingPin(Dia=PinOD,Len=0.0) {
PinLen = (Len != 0.0) ? Len : (4*Dia);
translate([0,0,-ThreadThick])
PolyCyl((Dia + 2*ThreadWidth),2*ThreadThick,4);
translate([0,0,-2*ThreadThick])
PolyCyl((Dia + 1*ThreadWidth),4*ThreadThick,4);
translate([0,0,-(PinLen/2 + ThreadThick)])
PolyCyl(Dia,(PinLen + 2*ThreadThick),4);
}
//----------------------
// Pieces
//-- LED strips
module OnePixel() {
render()
rotate([-90,0,0]) rotate(180) // align result the way you'd expect from the dimensions
difference() {
linear_extrude(height=Pixel[1],convexity=3)
polygon(points=LEDStripProfile);
translate([-Pixel[0]/2,Pixel[2],-PixelMargin[0]])
cube([Pixel[0],2*PixelMargin[2],2*PixelMargin[0]]);
translate([-Pixel[0]/2,Pixel[2],Pixel[1]-PixelMargin[0]])
cube([Pixel[0],2*PixelMargin[2],2*PixelMargin[0]]);
}
}
module LEDString(n = LEDStringCount) {
for (i=[0:n-1])
translate([0,i*Pixel[1]])
// resize([0,Pixel[1] + 2*Protrusion,0])
OnePixel();
}
//-- Stack of hard drive platters
module Platters(n = LEDStringCount + 1) {
color("gold",0.4)
for (i=[0:n-1]) {
translate([0,0,i*Pixel[1]])
difference() {
cylinder(d=Platter[OD],h=Platter[LENGTH],center=false,$fn=PillarSides);
cylinder(d=Platter[ID],h=3*Platter[LENGTH],center=true,$fn=PillarSides);
}
}
}
//-- Pillar holding the LED strips
module Pillar() {
difflen = PillarLength + 2*Protrusion;
// render(convexity=5)
difference() {
linear_extrude(height=PillarLength,convexity=4)
difference() {
rotate(180/(12*4))
circle(d=Platter[ID] - 1*ThreadWidth,$fn=PillarSides);
for (i=[0:LEDStripCount-1]) // clearance for LED beamwidth, may not actually cut surface
rotate(i*360/LEDStripCount)
translate([PillarCore/2,0,0])
polygon(points=BeamShape);
for (i=[0:LEDStripCount-1]) // LED front clearance
rotate(i*360/LEDStripCount)
translate([(PillarCore/2 + Pixel[2]),(Pixel[0] - 2*PixelMargin[0])/2])
rotate(-90)
square([Pixel[0] - 2*PixelMargin[0],Platter[ID]]);
}
for (i=[0:LEDStripCount-1]) // LED strip slots
rotate(i*360/LEDStripCount)
translate([PillarCore/2,0,-Protrusion])
linear_extrude(height=difflen,convexity=2)
rotate(-90)
polygon(points=LEDStripProfile);
difference() { // wiring recess on top surface, minus boss
for (i=[0,90])
rotate(i)
translate([0,0,(PillarLength - (WireSpace/2 - Protrusion))])
cube([(PillarCore + 2*Protrusion),Pixel[0] - 2*PixelMargin[0],WireSpace],center=true);
cylinder(d=3*Screw[OD],h=PillarLength + Protrusion,$fn=CapSides);
}
for (i=[0:LEDStripCount-1]) // wiring recess on bottom surface
rotate(i*90)
translate([PillarCore/2 - (WireSpace - Protrusion)/2,0,WireSpace/2 - Protrusion])
cube([WireSpace + Protrusion,Pixel[0] - 2*PixelMargin[0],WireSpace],center=true);
for (j=[0:LEDStringCount-1]) // platter spacer alignment pins
for (i=[0:LEDStripCount-1])
rotate(i*360/LEDStripCount + 180/LEDStripCount)
translate([(Platter[ID] - 1*ThreadWidth)/2,0,(j*Pixel[1] + Pixel[1]/2 + Platter[LENGTH]/2)])
rotate([0,90,0])
rotate(45)
LocatingPin();
translate([0,0,-Protrusion]) // central screw hole
rotate(180/4)
PolyCyl(Screw[ID],difflen,4);
if (false)
for (i=[-1,1]) // vertical wire channels
rotate(i*360/LEDStripCount + 180/LEDStripCount)
translate([PillarCore/2 - 2.0,0,-Protrusion])
PolyCyl(2.0,difflen,4);
for (i=[-1,1]) // locating pins
rotate(i*360/LEDStripCount - 180/LEDStripCount)
translate([PillarCore/2 - 2.0,0,0])
LocatingPin();
}
}
//-- Spacers to separate platters
module Spacers() {
difference() {
linear_extrude(height=Spacer[LENGTH],convexity=4)
difference() {
rotate(180/PillarSides)
circle(d=Spacer[OD],$fn=PillarSides);
for (i=[0:LEDStripCount-1]) // clearance for LED beamwidth, may not actually cut surface
rotate(i*360/LEDStripCount)
translate([PillarCore/2,0,0])
polygon(points=BeamShape);
for (i=[0:LEDStripCount-1]) // LED front clearance
rotate(i*360/LEDStripCount)
translate([(PillarCore/2 + Pixel[2]),(Pixel[0] - 2*PixelMargin[0])/2])
rotate(-90)
square([Pixel[0] - 2*PixelMargin[0],Platter[ID]]);
rotate(180/PillarSides)
circle(d=Spacer[ID],$fn=PillarSides); // central pillar fits in the hole
}
for (i=[0:LEDStripCount-1])
rotate(i*360/LEDStripCount + 180/LEDStripCount)
translate([Platter[ID]/2,0,(Pixel[1] - Platter[LENGTH])/2])
rotate([0,90,0])
rotate(45)
LocatingPin();
}
}
//-- Cap over top of pillar
module TopCap() {
difference() {
cylinder(d1=(Cap[OD] + Cap[ID])/2,d2=Cap[OD],h=Cap[LENGTH],$fn=CapSides); // outer lid
translate([0,0,-Protrusion])
PolyCyl(Screw[ID],Cap[LENGTH] + WireSpace + Protrusion,4); // screw hole
translate([0,0,Cap[LENGTH] - 2*WireSpace])
difference() {
cylinder(d=Cap[ID],h=2*Cap[LENGTH],$fn=CapSides); // cutout
cylinder(d=3*Screw[OD],h=Cap[LENGTH],$fn=CapSides); // boss
}
translate([0,0,Cap[LENGTH] - 2*ThreadThick])
cylinder(d=Cap[ID]/2,h=2*ThreadThick + Protrusion,$fn=CapSides); // recess boss
}
}
//-- Base below pillar
module Base() {
SideWidth = 0.5*Base[OD]*sin(180/BaseSides); // close enough
difference() {
union() {
difference() {
cylinder(d=Base[OD],h=Base[LENGTH],$fn=BaseSides); // outer base
translate([0,0,6*ThreadThick]) // main cutout
cylinder(d=Base[ID],h=Base[LENGTH],$fn=BaseSides);
rotate(180/BaseSides)
translate([0,0,Base[LENGTH] - BaseClearHeight/2]) // power connector hole
rotate([90,0,0]) rotate(180/8)
PolyCyl(CoaxConn[ID],Base[OD],8);
}
translate([0,0,Base[LENGTH]/2]) // recess pillar support below rim
cube([PillarCore,PillarCore,Base[LENGTH] - 2*ThreadThick],center=true);
}
for (i=[0:LEDStripCount-1]) // wiring recesses
rotate(i*90)
translate([PillarCore/2 - (WireSpace - Protrusion)/2,0,Base[LENGTH] - 4*WireSpace/2])
cube([WireSpace + Protrusion,PillarCore - 4*WireSpace,4*WireSpace],center=true);
translate([0,0,-Protrusion])
PolyCyl(Screw[ID],2*Base[LENGTH],4); // screw hole
translate([0,0,-Protrusion]) // screw head recess
rotate(180/8)
PolyCyl(8.5,Base[LENGTH] - 3.0 + Protrusion,8);
for (i=[-1,1]) // locating pins
rotate(i*360/LEDStripCount - 180/LEDStripCount)
translate([PillarCore/2 - 2.0,0,Base[LENGTH] - ThreadThick])
LocatingPin();
if (CablePort)
translate([0,Platter[ID]/2 + PCB[1],Base[LENGTH] - 3.0 + Protrusion])
rotate(-90)
cube([PCB[1],Base[OD],3.0]);
}
}
//----------------------
// Build it
if (Layout == "Pixel")
OnePixel();
if (Layout == "LEDString")
LEDString(LEDStringCount);
if (Layout == "Platters")
Platters(LEDStringCount + 1);
if (Layout == "Pillar")
Pillar(LEDStringCount);
if (Layout == "TopCap")
TopCap();
if (Layout == "Base")
Base();
if (Layout == "Spacers")
Spacers();
if (Layout == "Show") {
Pillar();
for (i=[0:LEDStripCount-1]) // LED strips
rotate(i*360/LEDStripCount)
translate([PillarCore/2,0,Platter[LENGTH]/2])
rotate([90,0,90])
color("lightblue") LEDString();
if (true)
for (j=[0:max(1,ShowDisks - 2)]) // spacers
translate([0,0,(j*Pixel[1] + Platter[LENGTH])])
color("cyan") Spacers();
for (j=[0:max(2,ShowDisks - 2)]) // spacer alignment pins
for (i=[0:LEDStripCount-1])
rotate(i*360/LEDStripCount + 180/LEDStripCount)
translate([(Platter[ID] - 1*ThreadWidth)/2,0,(j*Pixel[1] + Pixel[1]/2 + Platter[LENGTH]/2)])
rotate([0,90,0])
rotate(45)
color("Yellow",0.25) LocatingPin(Len=4);
translate([0,0,PillarLength + 3*Cap[LENGTH]])
rotate([180,0,0])
TopCap();
translate([0,0,-2*Base[LENGTH]])
Base();
if (ShowDisks > 0)
Platters(ShowDisks);
}
// Ad-hoc build layout
if (Layout == "Build") {
if (true)
Pillar();
if (true)
translate([0,(Platter[ID] + Cap[OD])/2,0])
TopCap();
if (true)
translate([0,-(Platter[ID] + Base[OD])/2,0])
Base();
Ybase = Spacer[OD] * (LEDStringCount%2 ? (LEDStringCount - 1) : (LEDStringCount - 2)) / 4;
if (true)
for (i=[0:LEDStringCount]) // build one extra set of spacers!
translate([(i%2 ? 1 : -1)*(Spacer[OD] + Base[OD])/2, // alternate X sides to shrink Y space
(i%2 ? i-1 : i)*Spacer[OD]/2 - Ybase, // same Y for even-odd pairs in X
0])
Spacers();
}
APRS tracks for my rides around Poughkeepsie in early November 2015:
APRS Coverage – Highland to Hopewell – 2015-11
Turning on the topo data and squinting at the Red Oaks Mill area:
APRS Coverage – Red Oaks Mill area topo – 2015-11
The topography isn’t in my favor, with two ridgelines between Red Oaks Mill and the two APRS nodes near Poughkeepsie. APRS coverage southwest of Red Oaks Mill along the Mighty Wappingers Creek (basically, Vassar Road) ranges from spotty to nonexistent, because that route has even worse topography.
Seems to me an APRSiGate in Red Oaks Mill, running Xastir (perhaps headless) on an RPi, conjured from my heap (perhaps with a shiny new TNC-Pi atop the RPi, rather than an ancient Kantronics KPC-9612), and using a vertical VHF antenna in the attic (because lightning), might improve the situation.
That whole project continues to slip into the future, but at least I have more motivation and linkies…
So Time Warner updated the infrastructure upstream of Mary’s folks and installed a new cable modem / router, which killed my remote access using ssh (with RSA keys, passphrases, nonstandard ports, fixed internal IP addresses, port forwarding, port triggers, and all the Right Stuff). I just spent a harried pair of days trying and failing to figure out how to make this work again.
My laptop can ssh into my file server from our house network, both wired and wireless. Ditto when it’s on the Squidwrench Operating Table. Ditto from the low-quality Hampton Inn WiFi near her folks. Plunked on their desk and jacked into their router, however, that outbound ssh times out somewhere between their bits and my basement.
I dinked with the TW Surfboard modem / router, added the appropriate port forwarding & triggers, dialed back the firewall intensity, and ssh flat out doesn’t work in either direction from any PC (all running various Linus flavors). No diagnostics, no logs, nothing that I could find.
From the outside (our house or the Hampton), there’s no response from the PCs inside (on their desk). I’m not trying a loopback from inside to inside, which I know doesn’t work with consumer-grade routers. I’d planned to ssh from there to my basement file server, then ssh back to verify that the connections worked, but the outbound connection doesn’t work.
Probably unrelated, but equally frustrating: trying to configure Thunderbird’s outbound SMTP with their email server flat-out doesn’t work. Either the username / password isn’t valid (it is), various combination of ports / security / encryption (including the ones in the TW FAQs) don’t survive the configuration test, or a seemingly valid configuration doesn’t actually transmit email. Incoming email works only in IMAP mode, not POP3.
I finally set up outbound TW email to bankshot through his Gmail account, which will probably have unforeseen side effects.
The usual Google searches were unavailing, other than several notes suggesting that if you have any other choice of ISP or email provider than TW, do that. But it’s not like they have any choice; Verizon provides 1 Mb/s (!) DSL in that area and satellite Internet isn’t going to happen in an apartment.
Obviously, I’m doing several things wrong, but I have no idea what else to try. I’ve set up email and remote access often enough to get a whole bunch of things right, but that sure didn’t help with TW.
Perhaps this is not nearly as motivational as it’s supposed to be:
Win 10 Upgrade Popup
A friend sent that along after reading my efforts to squelch the Windows 10 nagware on an off-lease Dell Optiplex that will never, ever be updated.
She just turned off automatic updates, which means she must examine all the updates and manually install ones that don’t download Win 10 (which she doesn’t want), forevermore. Unfortunately, that means she won’t automatically get all the security updates that help make current versions of Windows much less hazardous then in The Bad Old Days.
Talk about a Hobson’s Choice: in practical terms, you must decide between automatic updates or not getting regular updates. OK, that’s actually a false dilemma, but you get the idea.
Burnett at Rt 55 2015-11-08 – Yellow 5 s after green
Apparently, NYSDOT’s bicycle safety criteria allow greenlighting opposing vehicles onto bicyclists in the middle of intersections, so there’s no particular urgency to fix this non-problem.
They’ve been “studying” that situation, without contacting me for any further information, since July, so you can decide how much they’ve accomplished thus far. I know NYSDOT employees get offended when you call them liars to their face, but they have never, ever produced any evidence showing that I’m wrong.
Just to show why powering Neopixels directly from an Arduino is a Bad Idea, I wired up an Adafruit Jewel thusly (and, BTW, exactly like their lead illustration shows):
Makes your skin crawl just to look at it, right?
With all seven Neopixels set to a gray PWM (64,64,64), the average current should be around 90 mA: 21 * 18 mA * 64/255, with another 6% knocked off because the WS2812B controller imposes that much mandatory dark time at PWM 255.
Eyeballometrically, this looks pretty close at 100 mA/div:
Neopixel current 100 mA – 64-64-64 0-7 200 mA peak
But those seven asynchronous PWM oscillators guarantee this will happen every now & again:
Neopixel current 100 mA – 64-64-64 0-7 400 mA peak
The 400 mA peaks happen when all seven Neopixels turn on at once. The broad flat floor means they’re off most of the time and the power supply sees a hefty 400 Hz pulsating load.
The bottom trace shows the effect of those peaks in the top trace (at 200 mA/div) on the Arduino’s VCC pin:
Neopixel current 200 mA – 64-64-64 0-7 400 mA pk w VCC
That’s at 200 mV/div and AC coupled to remove the 5 VDC supply. Because the board runs from USB power, the on-board regulator doesn’t contribute to the problem, but there’s plenty of problem to go around.
Always use an external power supply and a 5 VDC regulator with Neopixels!
The Smell of Molten Projects in the Morning 