The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Electronics Workbench

Electrical & Electronic gadgets

CNC 3018-Pro: CAMTool Modification for MBI-style Home Switches

The Protonteer board I used on the MPCNC required a few additional pins for power to Makerbot-style home switches, so it’s no surprise the CAMTool V3.3 board on the CNC 3018-Pro gantry mill requires a similar hack:

3018 CNC CAMTool – Endstop power mod

The white jumper plugs into the single +5 V pin in the row and is soldered to a straight wire running along the entire row of header pins. I pushed the black plastic strip to the bottom, soldered the wire along the pins atop it, then clipped off the pins so they’re about the right height when flush against the PCB.

Use a two-row socket to hold the new row in alignment with the existing header:

3018 CNC CAMTool – Endstop power mod – alignment

Slobber on some epoxy and let it cure:

3018 CNC CAMTool – Endstop power mod – epoxy curing

And then It Just Works™:

3018 CNC CAMTool – Endstop power mod – installed

Well, after you install the switches and tell GRBL to use them …

Reminder: If you intend to put limit switches on both ends of the axis travel, you must clip the NC lead from both MBI switches. One switch per axis will work the way you expect and that’s how I’m using them here.

2019-08-13
Logitech “Quickcam for Notebooks Deluxe” USB Camera Disassembly
My collection of old USB cameras emitted a Logitech Quickcam for Notebooks Deluxe, with a tag giving a cryptic M/N of V-UGB35. Given Logitech’s penchant for overlapping names, its USB identifiers may be more useful for positive ID:
```
ID 046d:08d8 Logitech, Inc. QuickCam for Notebook Deluxe
```
It works fine as a simple V4L camera and its 640×480 optical resolution may suffice for simple purposes, even if it’s not up to contemporary community standards.

The key disassembly step turned out to be simply pulling the pivoting base off, then recovering an errant spring clip from the Laboratory Floor:

Logitech V-UGB35 USB Camera – mount removed

The clips have a beveled side and fit into their recesses in only one orientation; there’s no need for brute force.

Removing the two obvious case screws reveals the innards:

Logitech V-UGB35 USB Camera – PCB rear

Three more screws secure the PCB:

Logitech V-UGB35 USB Camera – PCB front

The ribbed focus knob around the lens makes it more useful than a nominally fixed-focus camera.

Reassembly is in reverse order.

I miss having obvious case screws …
2019-08-07
Warm-White LED Strip: FAIL

The roll of warm-white LEDs I used for the first sewing machine lights has evidently aged out:

Failed warm-white LED strip

They’ve been wrapped on their original roll, tucked in an antistatic bag, for the last five years, so it’s not as if they’ve been constantly abused.

All the cool-white LEDs on an adjacent roll in the same bag still work perfectly, so you’re looking at inherent vice.

I harvested the three longest functional sections and dumped the remainder in the electronics recycling box.

COB LEDs provide much more light, if only because they run at higher power densities, and seem to be much better cost-performers:

Juki TL-2010Q COB LED – installed – rear view

Admittedly, I haven’t looked at the RGB LED strips in a while, either.

2019-08-05
Baofeng UV-5R Squelch Settings

The Baofeng UV-5R radios on our bikes seem absurdly sensitive to intermodulation interference, particularly on rides across the Walkway Over the Hudson, which has a glorious view of the repeaters and paging transmitters atop Illinois Mountain:

Walkway Over The Hudson – Illinois Mountain Antennas

A better view of the assortment on the right:

Illinois Mountain – North Antennas

And on the left:

Illinois Mountain – South Antennas

Not shown: the Sheriff’s Office transmitter behind us on the left and the Vassar Brothers Hospital / MidHudson pagers on either side at eye level. There’s plenty of RFI boresighted on the Walkway.

Anyhow, none of the Baofeng squelch settings had any effect, which turned out to be a known problem. The default range VHF covered a whopping 6 dB and the UHF wasn’t much better at 18 dB, both at very low RF power levels.

We use the radios in simplex mode, generally within line of sight, so I changed the Service Settings to get really aggressive squelch:

Baofeng UV-5R – Improved Squelch Settings

I have no way to calibrate the new signal levels, but I’d previously cranked the squelch up to 9 (it doesn’t go any higher) and, left unchanged, the new level makes all the previous interference Go Away™. Another ride over the Walkway with the squelch set to 4 also passed in blissful silence.

If the BF-F9 levels mean anything on a UV-5R, that’s about -100 dBm, 20 dB over the previous -120 dBm at squelch = 9.

The new squelch levels may be too tight for any other use, which doesn’t matter for these radios. As of now, our rides are quiet.

[Update: Setting the squelch to 5 may be necessary for the Walkway, as we both heard a few squawks and bleeps while riding eastbound on a Monday afternoon. ]

2019-08-04
Vacuum Tube LEDs: Failed Tape, Failed USB Cable

While packing the vacuum tube LEDs for the HV Open Mad Science Fair, I noticed the knockoff Arduino Nano inside one had come unstuck from the base. It seems the double-stick foam tape I’d used had lost its sticky:

Vacuum Tube LEDs – unstuck foam tape

Replacing it with my now-standard black 3M outdoor rated tape ought to solve the problem forever more.

For whatever it’s worth, the SK6812 RGBW LEDs have had exactly zero failures in the last two years or so; I finally turned off the test fixture.

Before reassembling the light, I plugged the USB cable into the bench supply and watched the Nano reset erratically. Careful poking showed the USB cable was intermittent, so I carved it up:

Failed USB cable – autopsy

As far as I can tell, the black wire (supply common) was cut mostly all the way through, with just a few strands remaining, before I peeled the insulation back.

A closer look at the solder joints doesn’t inspire much confidence in their QC:

Failed USB cable – solder joints

If those pads tarnished along with their solder blobs, the overmolded plastic isn’t the right stuff for the job. If they started life like that … ick.

I must up my cable spend, although I have no confidence doing so will improve the quality.

2019-08-02
Exhibit Hand-Out Cards: QR Version
I’ve finally had it beaten into my head: any public exhibition requires paper handouts, if only for younger folks who are too shy to ask questions. Paper may seem obsolete, but it serves as a physical reminder long after the sensory overload of a busy event fades away.

Hence, I made up cards describing my exhibits at the HV Open Mad Science Fair, each sporting a QR code aimed at far more background information than anybody should care about:

Mad Science Fair – handout cards

The QR codes come from one-liners:
```
qrencode https://softsolder.com/?s=dso150 -s 5 -d 300 -o dso150.png
```
So, go ahead, shoot ’em with your phone:
Blog search QR code: astable
Blog search QR code: bowl-of-fire
Blog search QR code: dso150
Blog search QR code: halogen
Blog search QR code: hp7475a
Blog search QR code: tubes
Memo to Self: put the cards in the Big Box o’ Stuff the night before.
2019-07-30
Astable Multivibrator Blinkies: Radome Attachment

Ping-Pong ball radomes tend to fall off their perches at the slightest touch:

RGB LED – radome test

Because I planned to take my collection along to HV Open’s Mad Science Fair, I finally used a Round Tuit for some adhesive action.

The general plan was to punch a ring from double-sided tape, thusly:

Astable – Radome adhesive – poor surface

The OD required touching up the edge of a brass tube punch I’d made a while ago:

Astable – Radome adhesive – punch sharpening

It worked exactly as expected:

Astable – Radome adhesive – punching

Unfortunately, the 3D printed spider’s “spherical” socket has such a rough surface that the adhesive had too few contact points to hold the ball in place.

My fallback has become 3M outdoor-rated double-stick foam tape, so:

Astable – Radome adhesive – 3M foam tape

This leaves a small black ring visible between ball and socket. Recessing the foam tape by half its thickness should improve its ahem optics, although it’s probably not worth the effort with black PETG.

2019-07-29