Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
As part of spiffing my video presence for SquidWrench Zoom meetings, I put a knockoff RPi V1 camera into an Az-El mount, stuck it to a Raspberry Pi, installed the latest OS Formerly Known as Raspbian, did a little setup, and perched it on the I-beam over the workbench:
Raspberry Pi – workbench camera setup
The toothbrush head has a convenient pair of neodymium magnets affixing the RPi’s power cable to the beam, thereby preventing the whole lashup from falling off. The Pi, being an old Model B V 1.1, lacks onboard WiFi and requires a USB WiFi dongle. The white button at the lower right of the heatsink properly shuts the OS down and starts it up again.
Zoom can show video only from video devices / cameras attached to the laptop, so the trick is to make video from the RPi look like it’s coming from a local laptop device.
Start by exporting video from the Raspberry Pi:
raspivid --nopreview -t 0 -rot 180 -awb sun --sharpness -50 --flicker 60hz -w 1920 -h 1080 -ae 48 -a 1032 -a 'RPi Cam1 %Y-%m-%d %X' -b 1000000 -l -o tcp://0.0.0.0:5000
The -rot 180 -awb sun --sharpness -50 --flicker 60hz parameters make the picture look better. The bottom of the video image There is no way to predict which side of the video will be on the same side as the cable, if that’s any help figuring out which end is up, and the 6500 K LED tubes apparently fill the shop with “sun”.
The -l parameter causes raspivid to wait until it gets an incoming tcp connection on port 5000 from any other IP address, whereupon it begins capturing video and sending it out.
That’s the edge of the workbench over there on the left, looking distinctly like a cliff.
The RPi will happily stream video all day long to ffmpeg while you start / stop the display program pulling the bits from the video device. However, killing ffmpeg also kills raspivid, requiring a manual restart of both programs. This isn’t a dealbreaker for my simple needs, but it makes unattended streaming from, say, a yard camera somewhat tricky.
There appear to be an infinite number of variations on this theme, not all of which work, and some of which rest upon an unsteady ziggurat of sketchy / unmaintained software.
Addendum: If you have a couple of RPi cameras, it’s handy to run the matching ssh and ffmpeg sessions in screen / tmux / whatever terminal multiplexer you prefer. I find it easier to flip through those sessions with Ctrl-A N, rather than manage half a dozen tabs in a single terminal window. Your mileage may differ.
The general idea is to hold the wave washer (it’s mashed under the flat washer, honest) above those bumps on the plate holding the mirror and stalk balls. It’s a few millimeters from the end of a ¼ inch brass rod, drilled for the M3 screw, and reduced to 4.5 mm with a parting tool to clear the bumps.
While I was at it, I made two spare mirrors, just to have ’em around:
I should replace the steel clamp plates with a stainless-steel doodad of some sort to eliminate the unsightly rust, but that’s definitely in the nature of fine tuning.
Applesauce is completely optional. Should you prefer a softer & sweeter loaf, give it a try.
Conversely, reduce the sugar by about half if you’ve accustomed yourself to a keto-oid diet; the raisins carry enough sweetness for us. You can use brown sugar if you like.
Long ago and far away, I moved the keyboards off our desk surfaces to a more convenient location on a tray under the middle drawer. Mary’s desk recently gained a somewhat thinner keyboard with a thumbwheel volume control, so she wanted the tray moved up:
Keyboard Tray Relocation – in place
The supports on either side started out as 2×4 lumber with a slot cut (using the radial arm saw I no longer have) for the aluminum sheet:
Keyboard Tray Relocation – support view
For the record, a pair of screws hold each support to the drawer:
Keyboard Tray Relocation – support screw
Not elegant. Works fine. Good enough!
Tiny Bandsaw™ wasn’t designed for ripsawing lumber, but the same Proxxon 10/14 TPI blade I use for aluminum worked better than I expected to lop a 1-¼ inch strip from the wood slats:
Keyboard Tray Relocation – bandsaw fixture
That’s a reenactment based on a true story. The wood scraps clamped on the bandsaw table leave enough clearance for the 2×4 slide to freely, yet not enough for the blade to wander off track.
You can tell how long ago I built the original trays: nary a trace of 3D printing!
Well, it’s really zucchini bread season, with grated nutmeg among the spices (*):
Zucchini bread – minus QC sample
Having recently bought a very sharp grater, I hauled out a small vise to save my fingertips:
Nutmeg grating – mini-vise
The dark lunette comes from a previous clamping attempt; it takes a while to find the most secure pin arrangement.
Grate a flat:
Nutmeg grating – first flat
I’ve always enjoyed the surprisingly intricate patterns inside what looks like a bland nut.
Flip it over, flatten the other side, and grab it in an even smaller vise:
Nutmeg grating – flat clamping
In truth, that vise is intended for small cylinders, not flattened nuts, but I figured it’d suffice for light-duty use. Grate parallel to the vise screw, reclamp as needed, and it worked out reasonably well.
Eventually, you have a pile of powder and one cubic nutmeg:
Nutmeg grating – results
I’m sure there’s a way to grate the remaining cube, but I’m unwilling to shred my fingertips.
Tip the powder into a small jar and repeat as needed. Each nutmeg produces about 5 grams and I did three of the things this time.
Yummy!
(*) We omit the cloves and knock the sugar down by half. Your tastes will surely differ.
However, it’s worth noting my original, butt-ugly Az-El mounts lasted for all of those nine years, admittedly with adjustments along the way, which is far more than the commercial mountsmaking me unhappy enough to scratch my itch.
Scaling it down for a 10 mm polypropylene ball around the base of the 30 mm inspection mirror’s shaft simplified everything:
Helmet Mirror Ball Mount – drilled ball test
I’m reasonably sure I couldn’t have bought 100 polypro balls for eight bucks a decade ago, but we’ll never know. Drilling the hole was a complete botch job, about which more later. The shaft came from a spare mirror mount I made up a while ago; a new shaft appears below.
The solid model, like Gaul, is in three parts divided:
Helmet Mirror Ball Mount – Slic3r
The helmet plate (on the right) has a slight indent more-or-less matching the helmet curvature and gets a layer of good double-stick foam tape. The clamp base (on the left) has a pair of brass inserts epoxied into matching recesses below the M3 clearance holes:
Helmet Mirror Ball Mount – inserts
A layer of epoxy then sticks the helmet plate in place, with the inserts providing positive alignment:
Helmet Mirror Ball Mount – plates
The clamp screws pull the inserts against the plastic in the clamp base, so they can’t pull out or through, and the plates give the epoxy enough bonding surface that (I’m pretty sure) they won’t ever come apart.
I turned down a 2 mm brass insert to fit inside the butt end of the mirror shaft and topped it off with a random screw harvested from a dead hard drive:
Helmet Mirror Ball Mount – assembled – rear view
At the start, it wasn’t obvious the shaft would stay stuck in the ball, so I figured making it impossible to pull out would eliminate the need to find it by the side of the road. As things turned out, the clamp exerts enough force to ensure the shaft ain’t goin’ nowhere, so I’ll plug future shafts with epoxy.
The front side of the clamp looks downright sleek:
Helmet Mirror Ball Mount – assembled – front view
Well, how about “chunky”?
The weird gray-black highlights are optical effects from clear / natural PETG, rather than embedded grunge; it looks better in person. I should have used retina-burn orange or stylin’ black.
This mount is much smaller than the old one and should, in the event of a crash, not cause much injury. Based on how the running light clamp fractures, I expect the clamp will simply tear out of the base on impact. In the last decade, neither of us has crashed, so I don’t know what the old mount would do.
The clamp is 7 mm thick (front-to-back), set by the M3 washer diameter, with 1.5 mm of ball sticking out on each side. The model has a kerf one thread high (0.25 mm) between the pieces to add clamping force and, with the screws tightened down, moving the ball requires a disturbingly large effort. I added a touch of rosin and that ball straight-up won’t move, which probably means the shaft will bend upon droppage; I have several spare mirrors in stock.
On the other paw, the ball turns smoothly in the clamp and it’s easy to position the shaft as needed: much better than the old Az-El mount!
The inspection mirror hangs from a double ball joint which arrives with a crappy screw + nut. I epoxied the old mirror mount nut in place, but this time around I drilled the plates for a 3 mm stainless SHCS, used a wave washer for a bit of flexible force, and topped it off with a nyloc nut:
Helmet Mirror Ball Mount – mirror joint
I’m unhappy with how it looks and don’t like how the washer hangs in free space between those bumps, so I may eventually turn little brass fittings to even things out. It’s either that or more epoxy.
So far, though, it’s working pretty well and both units meet customer requirements.
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With a pair of fresh AA alkaline cells producing 3.1 V (not the NiMH Duracells you see in the picture), the blue LED blinks brightly.
The 610 mV peak voltage across R1 shows the LED starts at 25.4 mA:
LM3909 blue – 3.1 V – R1 24 ohm
The capacitor reaches 1 V, then goes about 150 mV into reverse charge during the flash (note the different horizontal scales):
LM3909 blue – 3.1 V – C1 V
The Darlington version of Q1 seems to do a decent job of keeping the cap out of reverse charge. A Shottky diode would add a few hundred mV, but I doubt there’s anything nasty going on inside the cap as it stands.
The Smell of Molten Projects in the Morning 