Improvements – Page 155 – The Smell of Molten Projects in the Morning

Command-Line CD Ripping, Redux

A slight improvement to my two-step manual CD ripping process, with the intent of avoiding any thoughts about abcde:

cdparanoia -B -v ; eject cdrom

Ejecting the CD after cdparanoid finishes with it provides a visual cue for the next step.

Set up the disk number and maximum number of tracks, then unleash lame:

d=1
tm=19
for t in $(seq -w 1 $tm) ; do lame --preset tape --tt "D${d}:T${t}" --ta "Michael Lewis" --tl "The Big Short" --tn "${t}/${tm}" --tg "Audio Book" --add-id3v2 track${t}.cdda.wav D${d}-${t}.mp3 ; done
rm track*

The $(seq -w 1 $tm) expansion generates a list of zero-filled numbers for the tracks.

There’s surely a one-liner to extract $tm, the maximum track number, from the track* files, but I’ll leave that for later.

You can increment the disk number with let "d++" if the ripping goes smoothly. If not, that’s fraught with peril, because you (well, I) will do it once too often.

Iterate for each CD in the set, washing & primping as needed for good results.

And that’s that, at least for a while…

2016-03-05

Streaming Player: Wireless Keypad

Moving the streaming media player control panel across the Sewing Room for E-Z access:

Wireless Keypad - colored labels — Wireless Keypad – colored labels

Stipulated: garish labels that don’t fit the keys well at all.

I need more than one stream for testing; the only one that matters is Classical.

The keypad uses the same 2.4 GHz ISM band as the Raspberry Pi’s Wifi radio, which means holding a key down (which should never happen) puts a dent in mplayer’s cache fill level. Even absent that interference, the WiFi link seems more than a little iffy, probably because it’s at the far end of the house and upstairs from the router.

Other WiFi devices report that 2.4 GHz RF has trouble punching through the intervening fifty feet of hardwood floor (on the diagonal, the joists amount to a lot of wood) and multiple sets of doubled wallboard sheets; the RPi probably needs a better radio with an actual antenna. I did move the WiFi control channel away from the default used by the (relatively distant) neighbors, which seemed to improve its disposition.

2016-03-04

Makerspace Starter Kit Available

For a variety of reasons that aren’t relevant here, I must dramatically reduce the amount of stuff in the Basement Laboratory / Machine Shop / Warehouse.

If you (or someone you know) has / is starting / will start a makerspace or similar organization, here’s an opportunity to go from zero to hero with a huge infusion of tools / instruments / make-froms / raw material / gadgets / surplus gear.

Think of it as a Makerspace Starter Kit: everything you need in one acquisition.

You’ve seen much of the stuff in these blog posts during the past five years, although I tightly crop the photos for reasons that should be obvious when you consider the backgrounds.

A few glimpses, carefully chosen to make the situation look much tidier than it really is:

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I’m not a hoarder, but I can look right over the fence into that territory…

I want to donate the whole collection to an organization that can figure out how to value it and let me write it off. Failing that, I’m willing to sell the whole collection to someone who will move it out and enjoy it / put it to good use / part it out / hoard it.

We can quibble over the value, which surely lies between scrap metal and filet mignon.

As nearly as I can estimate from our last two moves, I have 6±2 short tons of stuff:

Metal shop: old South Bend lathe / vertical mill-drill / bandsaw / hand tools / arbor press
Cabinets / shelves loaded with cutters / tools / micrometers / calipers / whatever
Gas & electric welding equipment, gas foundry furnace
Walls / bins / drawers of fasteners / wire nuts / plumbing fittings / pipe clamps / you-name-its
Bookshelves of references / magazines / databooks; I’ll keep at most one set of the magazines with my columns
Ham radio equipment / antennas / cables
Radial saw, blades, clamps, tooling, and a lumber / plywood stockpile
Labeled boxes of make-froms on steel shelving; you get the shelves, the boxes, and their contents.
Solvents, chemicals, metals, minerals, elements, etc.
Electronic / optical / mechanical surplus & doodads
Stockpiles of metal rods / pipes / beams / flanges / sheets / scrap parts
Tools & toys & treasures beyond your wildest imagination

When we left Raleigh, the moving company estimator observed “This will be like moving a Home Depot!”

You must take everything, which means you must have the ability & equipment to handle 6±2 tons of stuff in relatively small, rather heavy, not easily stackable lumps. You’ll need 1000+ square feet of space with at least a seven-foot ceiling on your end to unload the truck(s) and create a solid block of stuff with skinny aisles between the shelves. This is not a quick afternoon trip for you, your BFF, a pickup truck, and a storage unit.

I plan to keep the Sherline, the M2 3D printer, various small tools, some hardware / parts / stock, most of the electronic instruments (antique-ish, at best) and components, plus odds and ends. I’ll extract or clearly mark those items, leaving your team to move everything else without (too many) on-the-fly decisions.

I can provide photos and descriptions, but, realistically, you should evaluate the situation in person.

Although we’re not planning to move in the near future, if you’re thinking of moving into the Mid Hudson Valley and always wanted a house with a ready-to-run Basement Shop, we can probably work something out. Note: all of the online real estate descriptions, including Zillow, seem confused, as the two houses on our two-acre property contain the total square footage / rooms / baths / whatever. Contact us for the Ground Truth after you’ve contemplated the satellite view.

As the saying goes, “Serious inquiries only.”

2016-03-01

Adaptek AVA-2902E/I SCSI Card: Low Profile Bracket Hack

I picked up an Adaptek AVA-2902 SCSI card from eBay to use with an ancient Epson Perfection 636 SCSI scanner from the heap, but it came with a high-profile bracket wrapped around its DB-25 connector:

SCSI card bracket fix - before — SCSI card bracket fix – before

The old-school serial port card sitting atop it (from one of the off-lease Optiplexes in the stable) has a low-profile bracket that seemed promising, so I swapped the brackets.

Alas, the SCSI card positioned the DB-25 just a smidge higher than the serial card, putting the right-angle top of the bracket about 2 mm above the ledge, where it prevented the locking cover from engaging. I filed the bracket’s DB-25 mounting holes into ovals, using up all the slop around the connector shell, to no avail.

So I snipped off most of the bracket’s top, grabbed it in the bench vise, smashed the corner with a drift punch, and bashed the whole affair 2 mm lower. It fit reasonably well, although there’s an air gap near the bottom of the bracket where it tapers down to the guide slot. The SCSI connector barely fit, with some persuasion, under the locking cover:

SCSI card bracket fix - installed — SCSI card bracket fix – installed

Close enough for me; the scanner (looming over the SCSI connector) works fine and delivers much better image quality / color balance than the crappy HP 7400C with an auto-feeder that I’d been using.

SCSI cables look like gas pipes in this day & age of tiny USB cables and teensy HDMI connectors…

2016-02-29

LED Shoplight Conversion: Fluorescent Fixture Teardown

The weakest fluorescent shop light fixtures always fail during cold weather (apart from the usual early tube failures) and this winter’s cold spells triggered the usual carnage, so I picked up half a dozen (cheap) 22 W LED T8 tubes and set about rewiring three defunct (cheap) fluorescent fixtures from the recycle heap. The new LED tubes run directly from the AC line; you must remove the fluorescent fixture’s ballasts / capacitors / starters and rewire the “tombstone” lampholders accordingly.

The first challenge, as always, involved taking the fixtures apart. Turns out prying the endcap away from the fixture enough to clear the pair of bumps punched into the metal does the trick:

Fluorescent Shoplights - endcap latches — Fluorescent Shoplights – endcap latches

Each endcap contains the ballast inductor / choke and power-factor correction capacitor for one tube. The inductors from one shoplight had a fancy plastic tab that might have held the capacitor in place, but that’s about the only difference:

Fluorescent Shoplights - ballasts — Fluorescent Shoplights – ballasts

The 150 kΩ resistor has its leads twisted around the capacitor leads without benefit of that fancy solder stuff one might think necessary for a good connection.

The capacitor contacts use the minimum possible amount of material:

Fluorescent Shoplights - capacitor termination — Fluorescent Shoplights – capacitor termination

I think the caps use metallized Mylar film, but who knows?

The inductors measure 280 mH and the caps a whopping 5 µF. I might trust the inductors in a low-voltage circuit, but the caps have no redeeming features and went directly to the trash.

The starter PCB lived in the center of the fixture:

Fluorescent Shoplights - starter circuit — Fluorescent Shoplights – starter circuit

I deliberately picked LED tubes with the AC line contact on one end and the neutral contact on the other, so as to not put line and neutral contacts in the same tombstone. After rewiring, the neutral endcap looks like this:

Fluorescent Shoplights - neutral endcap — Fluorescent Shoplights – neutral endcap

The other endcap holds the power cord and has a green earth ground wire snaking out to a little tab passed into a slot punched in the metal case. I replaced the tab with an actual screw / solderless connector / toothed washer, but have no pix to show for it.

The LED tubes run at 6500 K and contrast harshly with the warm-white tubes in the fluorescent shoplights. I went with the highest light output, because even the best (cheap) LED tubes produce barely half the output of the fluorescents: 2000-ish lumens vs 3900-ish.

2016-02-26

Vacuum Tube LEDs: Platter Chassis

Given that Greenlee chassis punches fit the ersatz vacuum tube sockets, this makes a certain perverse sense:

This set of punches is probably worth its weight in, uh, tool steel, because Greenlee got out of the Radio Chassis Punch business quite a while ago:

Greenlee 730 Radio Chassis Punch Assortment

As far as a Greenlee punch is concerned, a hard drive platter looks a lot like thin aluminum sheet:

I lathe-turned that white bushing to align the hard drive platter around the screw inside the punch. The right way to make that bushing in this day & age definitely involves 3D printing, but I was standing next to the lathe and spotted a nylon rod in the remnants bucket underneath.

The inner ring crumples around the bushing inside the die, while the platter outside remains flat & undamaged through the entire experience.

I match-marked the socket & “plate cap lead” holes on the punched platter and introduced it to Mr Drill Press, but the right way to do that for more than one socket / plate involves a Sherline mill fixture and some CNC.

And then It Just Worked:

Vacuum Tube LEDs - IBM 21HB5A drive platter socket — Vacuum Tube LEDs – IBM 21HB5A drive platter socket

That’s obviously a proof of concept; the socket rests on the desk with the rest of the tubes / sockets / Neopixels tailing off to the right. The plate cap lead should pass through a brass tube fitting on the platter, just for pretty.

The 7- and 9-pin sockets have a raised disk that’s slightly smaller than the 25 mm hard drive hole; the easiest fix involves slightly enlarging the disk to match the hole. Although CDs / DVDs have a 15 mm hole and Greenlee punches work surprisingly well on polycarbonate, if I’m going to CNC-drill the screw / wire holes anyway, CNC milling the middle hole should go quickly and eliminate a messy manual process.

Come to think of it, that big tube would look better in the middle of a DVD amid all those nice diffraction patterns from the RGB LEDs in the cap…

2016-02-25

Improved Lip Balm / Lipstick Holder

Mary asked for a less angular version of the Lip Balm Holder, which gave me a chance to practice my list comprehension:

You hand the OpenSCAD program a list of desired tube diameters in the order you want them, the program plunks the first one (ideally, the largest diameter) in the middle, arranges the others around it counterclockwise from left to right, then slips a lilypad under each tube.

As long as you don’t ask for anything egregiously stupid, the results look reasonably good:

Improved Lipstick and Balm Holder - 8 tubes — Improved Lipstick and Balm Holder – 8 tubes

As before, each tube length is 1.5 times its diameter; the lipsticks / balms fit loosely and don’t flop around.

Given the tube diameters and the wall thickness, list comprehensions simplify creating lists of the radii from the center tube to each surrounding tube, the center-to-center distances between each of the outer tubes, and the angles between successive tubes:

// per-tube info, first element forced to 0 to make entries match RawDia vector indexes

Radius = [0, for (i=[1:NumTubes-1]) (TubeRad[0] + TubeRad[i] + Wall)];			// Tube[i] distance to center pointRadius = [0, for (i=[1:NumTubes-1]) (TubeRad[0] + TubeRad[i] + Wall)];			// Tube[i] distance to center point
echo(str("Radius: ",Radius));

CtrToCtr = [0, for (i=[1:NumTubes-2]) (TubeRad[i] + TubeRad[i+1] + Wall)];		// Tube[i] distance to Tube[i+1]
echo(str("CtrToCtr: ",CtrToCtr));

Angle = [0, for (i=[1:NumTubes-2]) acos((pow(Radius[i],2) + pow(Radius[i+1],2) - pow(CtrToCtr[i],2)) / (2 * Radius[i] * Radius[i+1]))];
echo(str("Angle: ",Angle));

TotalAngle = sumv(Angle,len(Angle)-1);
echo(str("TotalAngle: ",TotalAngle));

The angles come from the oblique triangle solution when you know all three sides (abc) and want the angle (C) between a and b:

C = arccos( (a² + b² - c²) / (2ab) )

Peering down inside, the Slic3r preview shows the lily pads are the tops of squashed spheres:

Improved Lipstick and Balm Holder - Slic3r preview — Improved Lipstick and Balm Holder – Slic3r preview

The pads are 2.0 times the tube diameter, which seemed most pleasing to the eye. They top out at 2.0 mm thick, which might make the edges too thin for comfort.

Update: Here’s what it looks like with a convex hull wrapped around all the lilypads:

Improved Lipstick and Balm Holder - hulled base — Improved Lipstick and Balm Holder – hulled base

I’m awaiting reports from My Spies concerning the typical diameter(s) of lipstick tubes, then I’ll run off a prototype and see about the lily pad edges.

The OpenSCAD source code as a GitHub gist:

	// Lipstick and Balm Tube Holder
	// Ed Nisley KE4ZNU – February 2016

	//- Extrusion parameters – must match reality!

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

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

	Protrusion = 0.1;

	HoleWindage = 0.2;

	//——
	// Dimensions

	RawDia = [26,21,19,17,19,21]; // actual tube diameters in desired order, center = largest first
	NumTubes = len(RawDia);

	Clearance = 2.0;

	TubeDia = [for (i=[0:NumTubes-1]) (RawDia[i] + Clearance)]; // actual tube diameters
	TubeRad = TubeDia / 2;

	echo(str("NumTubes: ",NumTubes));

	Wall = 2.0;

	BaseThick = 2.0;
	BaseFactor = 2.0;

	NumSides = 8*4;

	// per-tube info, first element forced to 0 to make entries match RawDia vector indexes

	Radius = [0, for (i=[1:NumTubes-1]) (TubeRad[0] + TubeRad[i] + Wall)]; // Tube[i] distance to center point
	echo(str("Radius: ",Radius));

	CtrToCtr = [0, for (i=[1:NumTubes-2]) (TubeRad[i] + TubeRad[i+1] + Wall)]; // Tube[i] distance to Tube[i+1]
	echo(str("CtrToCtr: ",CtrToCtr));

	Angle = [0, for (i=[1:NumTubes-2]) acos((pow(Radius[i],2) + pow(Radius[i+1],2) – pow(CtrToCtr[i],2)) / (2 * Radius[i] * Radius[i+1]))];
	echo(str("Angle: ",Angle));

	TotalAngle = sumv(Angle,len(Angle)-1);
	echo(str("TotalAngle: ",TotalAngle));


	//———————-
	// Useful routines

	// vector sum cribbed from doc

	function sumv(v,i,s=0) = (i==s ? v[i] : v[i] + sumv(v,i-1,s));

	//———————-
	//- Build it

	for (i=[0:NumTubes-1])
	rotate(90 – TotalAngle/2 + sumv(Angle, (i>0) ? (i-1) : 0))
	translate([Radius[i],0,0]) {
	resize([0,0,2*BaseThick]) // bases
	difference() {
	sphere(r=BaseFactor*TubeRad[i],$fn=NumSides);
	translate([0,0,-BaseFactor*TubeDia[i]])
	cube(2BaseFactorTubeDia[i],center=true);
	}
	difference() { // tubes
	cylinder(r=TubeRad[i] + Wall,h=1.5*TubeDia[i] + BaseThick,$fn=NumSides);
	cylinder(d=TubeDia[i],h=1.5*TubeDia[i] + BaseThick + Protrusion,$fn=NumSides);
	}
	}

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2016-02-23