Posts Tagged Improvements
CNC 3018-Pro: Probe Camera Case for Anonymous USB Camera
Posted by Ed in Electronics Workbench, Machine Shop, Photography & Images on 2019-09-03
The anonymous USB camera I used with the stereo zoom microscope not only works with VLC, but also with bCNC, and it has a round PCB with ears:
Which suggested putting it in a ball mount for E-Z aiming:
Black filament snippets serve as alignment pins to hold the ball halves together while they’re getting clamped. They’re epoxied into the upper half of the ball, because who knows when I’ll need to harvest the camera.
The clamp mount descends from the Tour Easy Daytime Running Lights, with more screws and less fancy shaping:
The clamp pieces fit around the ball with four M3 screws providing the clamping force:
The whole affair sticks onto the Z axis carrier with double-sided foam tape:
It barely clears the strut on the -X side of the carriage, although it does stick out over the edge of the chassis.
After the fact, I tucked a closed-cell foam ring between the lens threads and the ball housing to stabilize the lens; the original camera glued the thing in place, but some fiddly alignment & focusing lies ahead:
It’s worth noting that the optical axis of these cheap cameras rarely coincides with the physical central axis of the lens. This one requires a jaunty tilt, although it’s not noticeable in any of the pictures I tried to take.
All in all, this one works just like the probe camera on the MPCNC.
The OpenSCAD source code as a GitHub Gist:
CNC 3018-Pro: Probe Camera Case for Logitch QuickCam Pro 5000
Posted by Ed in Electronics Workbench, Machine Shop, Photography & Images, Software on 2019-09-02
The ball-shaped Logitch QuickCam Pro 5000 has a rectangular PCB, so conjuring a case wasn’t too challenging:
That’s more-or-less matte black duct tape to cut down reflections.
The top side has a cover made from scuffed acrylic scrap:
The corners are slightly rounded to fit under the screw heads holding it in place.
The solid model shows off the internal ledge positioning the PCB so the camera lens housing rests on the floor:
The notch lets the cable out, while keeping it in one place and providing some strain relief.
I though if a camera was recognized by V4L2 and worked with VLC, it was good to go:
Regrettably, it turns out the camera has a pixel format incompatible with the Python opencv interface used by bCNC. This may have something to do with running the code on a Raspberry Pi, rather than an x86 box.
The camera will surely come in handy for something else, especially with such a cute case.
The OpenSCAD source code as a GitHub Gist:
Monthly Science: Weight
Another two months of dots for the record:
The eyeballometric slope continues at 1 lb/month.
I started low-key upper-body strength training in June with encouraging results: my biceps no longer require exotic instrumentation for detection and my abs may soon transition from “throw pillow” to “two-pack”.
This is, however, the season of bounteous garden harvests, including delicious corn-on-the-cob and summer squash …
Rt 376: Clearcut From Red Oaks Mill to Maloney Rd
Posted by Ed in Oddities, Recumbent Bicycling on 2019-08-31
NYS DOT Region 8 Dutchess South recently did enough over-the-rail clearcutting to make Rt 376 bicycle-able from Red Oaks Mill to Maloney Rd!
To the best of our memories and judging from the tree stumps along the rail, it’s been a decade since DOT last clearcut that section; the Japanese Knotweed has definitely taken over since then.
Here’s what the Knotweed looked like in June, just north of Maloney Rd, after a trimming in May:
Now, it’s not nearly so snug out there:
Here’s a slide show starting with Dutchess North’s routine grass mowing in Red Oaks Mill and ending with Dutchess South’s clearcut just north of Maloney Rd:
The Wappinger Creek bridge seems to be a no man’s land between the two Residencies, but we can generally take the lane:
We hope Dutchess South’s over-the-rail maintenance will become an annual event and prevent the brush from taking over again.
CNC 3018-Pro: Platter Fixtures
Posted by Ed in Machine Shop, Software on 2019-08-30
Up to this point, the Sherline has been drilling 3.5 inch hard drive platters to serve as as reflecting bases for the vacuum tubes:
The CNC 3018-Pro has a work envelope large enough for CD / DVD platters, so I mashed the Sherline fixture with dimensions from the vacuum tube code, added the 3018’s T-slot spacing, and conjured a pair of fixtures for a pair of machines.
Because I expect to practice on scrap CDs and DVDs for a while:
And a 3.5 inch hard drive platter version:
The holes sit at half the 3018’s T-slot spacing (45 mm / 2), so you can nudge the fixtures to the front or rear, as you prefer.
The alignment dots & slots should help touch off the XY coordinate system on the Sherline, although it can’t reach all of a CD. Using bCNC’s video alignment on the hub hole will be much easier on the 3018.
After fiddling around with the 3018 for a while, however, the CD fixture doesn’t have many advantages over simply taping the disc to a flat platen. Obviously, you’d want a sacrificial layer for drilling, but it’s not clear the OEM motor / ER11 chuck would be up to that task.
The OpenSCAD source code as a GitHub Gist:
CNC 3018-Pro: DRV8825 Hack for 1:8 Microstep Mode
Posted by Ed in Electronics Workbench, Machine Shop on 2019-08-28
The CAMTool V3.3 board on the CNC 3018-Pro hardwires the three DRV8825 stepper driver chips in 1:32 microstep mode by pulling all three Mode pins high. Unlike most CNC boards, it does not include jumpers to let you select different microstep modes; the designers know you want as many microsteps as you can possibly get.
As it turns out, 1:32 microstep mode requires 1600 steps for each millimeter of travel and, because GRBL tops out around 30 k step/s, the maximum speed is about 18.75 mm/s = 1125 mm/min. Which isn’t at bad, but, because I intend to use the thing for engraving, rather than the light-duty machining it’s (allegedly) capable of performing, running at somewhat higher speeds will be desirable.
For sure, a 3018-Pro does not have a physical resolution of 625 nm.
If you’re willing to settle for a mere 400 step/mm = 2.6 µm, then you can just ground the Mode 2 pin to get 1:8 microstep mode:
Rewiring the CAMTool board isn’t feasible, but hacking the DRV8825 carrier PCB doesn’t require much effort.
So, we begin.
Clamp the PCB in a vise, grab the Mode 2 pin with a needle-nose pliers, apply enough heat to melt the solder completely through the board, and yank that pin right out:
I do wonder how the layout folks managed to reverse the “N” for the Enable pin. Perhaps it’s a Cyrillic И in a dead-simple font?
With that done, add a snippet of wire from M2 to the GND pin in the opposite corner to complete the job:
Despite that picture, remember to plug the DRV8825 boards into the CAMTool V3.3 board with the heatsink downward and the twiddlepot on the top, as shown in the little instruction book you got with the hardware:
Recompute the step/mm value in 1:8 microstep mode:
400 step/mm = (200 full step/rev) × (8 microstep/full step) / (4 mm/rev)Then set the corresponding GRBL parameters:
$100=400
$101=400
$102=400The 3018-Pro should work exactly like it did before, maybe a little noisier if your ears are up to the task.
Moah Speed comes later …
CNC 3018-Pro: CAMTool V3.3 USB Power Diode
Posted by Ed in Electronics Workbench, Machine Shop on 2019-08-27
The CAMTool V3.3 board dispenses with fancy USB power switching circuitry:
The NUP2201 is an ESD clamp diode / suppressor IC, which is a nice touch, but FU1, a simple 300 mA polyfuse, is the only thing standing between the USB cable and the on-board +5 V regulator. In real life, it looks like this:
It’s the little black rectangle between the USB jack and the CH340 USB-to-serial chip. The
The far end of the USB cable plugs into a Raspberry Pi, a device known for unseemly fussiness about USB power, so I unsoldered the fuse and installed a diode:
It’s a BAT54 Schottky diode, pointed toward the right to prevent current from the board getting to the Pi. Pin 2 (toward the bottom) isn’t connected to anything inside the package, either, so it’s all good.
I suppose if one were a stickler for detail, one could gimmick the diode in series with the fuse, but I figured that’s a solution for a problem well down on the probability list …
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