Archive for category Photography & Images

Photo Lamp Mount: Moah Plastic!

One of the cold shoe mounts I made for the photo lamps cracked:

Photo Lamp Mount - fractured
Photo Lamp Mount – fractured

It’s done in PETG with my more-or-less standard two perimeter threads and 15% 3D honeycomb infill, which is Good Enough™ for most of my parts. In this case, there’s obviously not nearly enough plastic in there!

Redoing it with three perimeters and 50% infill should improve the situation, even though it looks identical on the outside:

Photo Lamp Mount - reinstalled
Photo Lamp Mount – reinstalled

I didn’t replace the other mount. If it breaks, it’ll get the same 50% infill as this one. If this one breaks, I’ll try 75%.

An easy fix!

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Monthly Image: Digital Machinist 14.4 Cover

I ain’t getting richer, but I did get mah pitcher onna cover of th’ Digital Machinist:

Digital Machinist Cover DM14.4 - Winter 2019
Digital Machinist Cover DM14.4 – Winter 2019

I just caught George Bulliss in a weak moment. [grin]

It’s the diamond drag holder on the CNC 3018-Pro, before the XL axis extension hackage., with the probe camera stuck to the left side.

You can say you knew me before …




A quartet of defunct 64 KB EEPROMs (*) emerged from a box of microscope doodads, so I stuck ’em under the stereo zoom scope for final pictures.

The oldest one, an MCM68764, came from Motorola with a 8313 date code. The next three, all TMS2764JL-25, came from TI with date codes in 84 and 85, so they have slightly different layouts.


This one is rotated 90° counterclockwise:


The hideous compression artifacts come from the original Pixel 3a images, because they’re (digitally) zoomed in all the way, plus bonus optical distortion from the quartz windows. The chips definitely look better in person, although the (optical) magnification isn’t nearly enough to show the tiniest details.

(*) Uh, they’re just EPROMs. It’s been so long since I’ve typed it that the extra “E” just stuttered right out. That’s my story and I’m sticking with it … at least I got the image names right!


Homage Tektronix Circuit Computer: Paper Matters

To judge from the dislodged pigment grains, the original Tektronix Circuit Computer probably used then-new laser printing on good-quality paper, laminated between plastic sheets:

Tek CC - OEM
Tek CC – OEM

A Pilot Precise V5RT cartridge on plain paper (20 lb 98 white), also laminated, looks pretty good:

Tek CC - V5RT green - 20 lb plain paper
Tek CC – V5RT green – 20 lb plain paper

But a black V5RT pen on HP Glossy Presentation Paper (44 lb, 160 g/m²), also laminated, is spectacular:

Tek CC - V5RT black - glossy presentation paper
Tek CC – V5RT black – glossy presentation paper

The glossy Presentation paper is hard enough to keep the pen ball from sinking in, producing much finer lines. In round numbers:

  • 0.2 mm – Tek laser-printed (?) original
  • 0.3 mm – green V5RT on plain paper
  • 0.2 mm – black V5RT on glossy Presentation paper

The CNC 3018XL plotted / drew everything at 2400 mm/min = 40 mm/s, with minimal wobbulation in the lines and none worth mentioning in the characters.

The pen ball sometimes pulls a dot of ink off the glossy paper as it rises at the end of a stroke; perhaps matte paper would produce more traction on the ink.

You can see small blobs at the end of some strokes, but the fancy paper prevents most of the bleeding visible in the previous tests. Pilot V5 pens definitely dislike card stock.

The results looks great in person without magnification, so maybe none of that matters.

The pix come from the Pixel 3a camera in its microscope adapter.

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1 Comment

Merry Christmas

Moonrise, as seen through the pines in our yard:

Pixel 3a Night Vision - moonrise
Pixel 3a Night Vision – moonrise

The Pixel 3a produces exceedingly useful low-light images, mostly by having Google’s software compensate for its tiny lens and minimal light-capture area, with the downside of turning a peaceful night scene into harsh daylight.

Take the rest of the day off, OK?


Google Pixel 3a Microscope Adapter

Hand-holding my Google Pixel 3a phone over the microscope eyepiece worked well enough to justify building Yet Another Camera Adapter:

Pixel 3a Microscope Adapter - in action
Pixel 3a Microscope Adapter – in action

The solid model looks about like you’d expect:

Google Pixel 3a Zoom Microscope Mount - solid model - top
Google Pixel 3a Zoom Microscope Mount – solid model – top

The “camera” actually has the outside dimensions of a Spigen case, rather than the bare phone, because dropping a bare phone is never a good idea.

The base plate pretty much fills the M2’s platform:

Pixel 3a Microscope Adapter - M2 platform
Pixel 3a Microscope Adapter – M2 platform

I originally arranged the four corners around the plate to print everything in one go, but an estimated six hours of print time suggested doing the corners separately would maximize local happiness. Which it did, whew, even if the plate ran for a bit over 4-1/2 hours.

The snout is a loose fit around the 5× widefield microscope eyepiece, with the difference made up in a wrap of black tape; it’s much easier to adjust the fit upward than to bore out the snout. An overwrap of tape secures the snout to the eyepiece, which I’ve dedicated to the cause; the scope normally rocks 10× widefield glass.

The tapered hole exposes the phone’s fingerprint reader to simplify unlocking, should it shut down while I’m fiddling with something else.

The microscope doesn’t fully illuminate the camera’s entrance pupil at minimum zoom, with 4.5× filling the screen and (mostly) eliminating the vignette. The corner blocks have oversize holes to allow aligning the camera lens axis over the microscope optical axis. The solid model incorporates Lessons Learned from the version you see here, because you (well, I) can’t measure the camera axis with respect to the outside dimensions accurately enough:

Pixel 3a Microscope Adapter - installed - front
Pixel 3a Microscope Adapter – installed – front

Although it’s less unsteady than it looks, microscopy requires a gentle touch at the best of times. The adapter doesn’t add much wobble to the outcome:

Pixel 3a Microscope Adapter - installed - side
Pixel 3a Microscope Adapter – installed – side

The field is about 14×19 mm with the camera at 4.5× and the microscope at minimum zoom:

Pixel 3a Microscope Adapter - test image - min mag
Pixel 3a Microscope Adapter – test image – min mag

You can see a little darkening on the upper and lower right corners, so the phone’s still minutely leftward.

The field is about 1.5×2 mm at full throttle:

Pixel 3a Microscope Adapter - test image - max mag
Pixel 3a Microscope Adapter – test image – max mag

Color balance with the cold white LED ring isn’t the best, but it’s survivable. Mad props to OpenCamera for exposing All. The. Controls. you might possibly need.

The OpenSCAD source code as a GitHub Gist:

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Homage Tektronix Circuit Computer: Ball-point Pens vs. Paper

Extra Fine Pilot V5 pens have a 0.5 mm ball, in contrast to the 1.0 mm ball in the cheap pens I’ve been using, so they should produce much finer lines.

Which turns out to be the case:

Tek Circuit Computer - pen and paper comparison
Tek Circuit Computer – pen and paper comparison

That’s a stack of three “Homage” Tek CC bottom decks under a Genuine Tektronix Circuit Computer.

The black scale at the top of the picture (and the bottom of the stack) came from a 1 mm cheap pen in the collet holder, the two green scales come from a 0.5 mm Pilot V5RT cartridge in its new holder, and the Original is (most likely) laser-printed back when that was a New Thing.

As always, paper makes a big difference in the results. The brownish paper is 110 pound card stock with a relatively coarse surface finish. The white paper is ordinary 22 pound general-purpose laser / inkjet printer paper.

The 1.0 mm pen (top) doesn’t much care what it’s writing on, producing results on the low side of OK: some light sections, no blobs. Perfectly serviceable, but not pretty.

1.0 mm ball pen
1.0 mm ball pen

The Pilot V5RT really likes better paper, as it bleeds out on the card stock whenever the CNC 3018XL so much as pauses at the end of a stroke. Using white paper slows, but doesn’t completely stop, the bleeding, making the blobs survivable.

0.5 mm ball Pilot V5RT pen
0.5 mm ball Pilot V5RT pen

I’ve been using card stock to get stiffer, more durable, and more easily manipulated decks, but the improved line quality on the white paper says I should laminate the decks in plastic, just like the original Tektronix design.

No surprise there!

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