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: Photography & Images

Taking & making images.

Prusa MK4: Camera Mount Bird’s Nest

Having just set up the camera to watch the Prusa MK4’s platform, this situation caught my eye while sitting in the Comfy Chair at my desk:

Prusa MK4 – Bird Nest – A

~~(The camera in the lower right doesn’t yet record videos, so you must imagine what I saw.)~~ I forgot capturing this screenshot:

Prusa MK4 – Bird Nest – platform camera

The nozzle was busily adding to the tangle, so I shut the printer off and trotted to the Basement Shop™ to find two more parts lying dead on the workbench:

Prusa MK4 – Bird Nest – B

This was entirely my fault, as I’d ignored PrusaSlicer’s warning about inadequate adhesion for the camera mount link standing in the corner:

Prusa MK4 – Camera Mount Links – slicer preview

That’s the PrusaSlicer preview after adding a wider brim and painting more support structures on all three parts. Given larger footprints, the next attempt completed without drama, which is the normal outcome.

Moral of the story: Tall skinny parts need more surface area on the platform than you think, even with excellent adhesion.

2026-05-21
Prusa MK4 Camera Lighting
Although the Raspberry Pi camera has a good view of the Prusa MK4’s extruder, there’s not much light under there:

RPi Camera Mount – image

There’s also not much room for a lighting fixture on the printer where it must mount, so I modified a trio of nominally 12 V / 4 W COB LED panels:

Prusa MK4 – Extruder sidelight – COB LEDs

Their “4 W” rating seems aspirational, at best, as a 12 VDC supply pushes only 75 mA through the panel, so they tick along at 900 mW. If you expect cheap eBay / Amazon components to live up to their specs, dream on.

The modifications:
- Unsolder the pins
- Crunch off the surprisingly precise 27.4 Ω SMD resistor
- Clean up the rubble
- Wire the panels directly in series, ignoring their bridge rectifiers
The 15 LEDs on each panel are arranged in five parallel chains of three LEDs for a total forward drop of 8.3 V, so putting three panels in series works with the MK4’s 24 V power supply.

Stick them onto the MK4 power supply case with foam tape and wire them directly to the 24 V terminals:

Prusa MK4 – Extruder sidelight – installed

There’s very little clearance between the machine frame and the X Axis carriage on the threaded rod. Putting the LEDs in a 3D printed case and routing the wires lower on the column would be nice touches:

Prusa MK4 – Extruder sidelight – front view

The panels start at 30 mA when cold and drop to 25 mA as they warm up in the 63 °F = 17 °C Basement Shop. Each panel dissipates 250 mW: bright enough for the task, dim enough to avoid overpowering the camera’s limited dynamic range, and definitely within whatever power rating they should have.

Looking over the camera’s shoulder in normal shop lighting suggests it’s about right:

Prusa MK4 – Extruder sidelight – camera overview

A staged scene with the shop lights turned off:

Prusa MK4 – Extruder sidelight – low-light view

Call it Good Enough™ for the purpose.
2026-05-20
RPi Camera RTSP Setup
The rpicam.cfg file holding the parameters for the Raspberry Pi watching the Prusa MK 4 printer:
```
bitrate=2000000 
framerate=15
timeout=0 
nopreview= 
codec=libav 
libav-format=mpegts 
width=1280
height=720
rotation=180
roi=0.00,0.00,1.0,1.0
hdr=auto
```
The RPi camera for the wren nest is just taped to the window, but has a configuration providing a bigger picture:
```
bitrate=2000000 
framerate=15
timeout=0 
nopreview= 
codec=libav 
libav-format=mpegts 
width=1920 
height=1080 
roi=0.00,0.00,1.0,1.0
hdr=auto
```
The useful pieces:
- bitrate sets the average data rate, which may be too high for comfort outside your immediate LAN
- framerate need not be as high as you think
- nopreview prevents a preview picture while starting
- width and height do the obvious thing, but don’t try to be too clever
- roi picks the image from a specific part of the camera sensor, so you can adjust the image layout if you have a rigidly fixed camera
- hdr doesn’t do anything for cheap RPi cameras
Putting all the fiddly config in a file reduces the command line invocation to a mere jawbreaker:
```
rpicam-vid --config rpicam.cfg -o - | cvlc stream:///dev/stdin --sout '#rtp{sdp=rtsp://:5886/wrens}' &
```
Although you’d want to set that up to run automagically when the RPi starts up, for now I just fire it off as needed through an SSH session, with the ampersand letting it run after that terminal session closes.

The RTSP port (5886) and stream (wrens) can be anything you like, which comes in handy when squirting streams through port-forwarded firewall pinholes using a router that cannot handle different external and internal port numbers.

Useful background info:
2026-05-18
House Sparrow vs. House Wren vs. Entrance Reducer

A friend gave Mary a small-bird birdhouse, which immediately attracted the attention of a pair of House Wrens:

Bird House entrance reducer – wren exiting

The vertical black bar is a DIY Birdsaver cord.

The entrance hole was 1-½ inch ⌀, a bit larger than the 1 inch ⌀ preferred by wrens and entirely suitable for the pair of House Sparrrows who also took an interest in the property:

Bird House – sparrow inside

This led to considerable discussion and displays of outright hostility:

Bird House entrance reducer – wren vs sparrow

Sparrows and wrens disagree on nestbuilding materials, with the wrens hauling twigs into the box and sparrows hauling them back out again.

Because wrens have better PR agents than sparrows, I intervened by taking the box apart:

Bird House – nest base sticks

Although I realize that’s a lot of work for a small bird, I dumped the contents off the patio and set about reducing the entrance hole:

Bird House – interior cleared

Because birds aren’t too fussy about looks, I sawed off half an inch of 1 inch (ID) CPVC pipe and glued it in the hole:

Bird House entrance reducer – interior glue

The outside looks marginally better:

Bird House entrance reducer – exterior glue

The sparrows continued to approach the hole at full throttle, deploying landing gear and speed brakes at the last possible moment:

Bird House entrance reducer – sparrow approach

But they no longer fit through the hole and eventually gave up trying. The wrens resumed hauling twigs, although we’re not certain they’ll finish the project, as birds tend to build several partial nests before selecting the final one.

We hope this will end on a happier note than last year’s Wreath Robins.

2026-05-13
Walkway Over the Hudson: Camera LEDs

Under the plausible assumption the security / surveillance cameras along the Walkway Over the Hudson aren’t the cheapest junk available from a randomly named Amazon seller, this came as a surprise during a recent Walkway At Night stroll:

Walkway Over the Hudson – camera LEDs

The IR LEDs emit just enough red light to be dimly visible to the human eye, but appear much brighter to a silicon detector. I think the long gap at the bottom right is a sensor of some sort, so the array of 18 LEDs has two deaders, one near death, and six more fading away.

The necklace lights on the Mid-Hudson Bridge are once again in good repair:

Mid-Hudson Bridge – 2026-04-24

They were showing fixed white light, rather than a moving color display, but it’s still a nice effect.

2026-04-27
Image Trace and Cut

Having admired the paper craft at RavensBlight and with some experience in simple paper cuttery, I had to try my hand at the Ghost Truck. Rather than using an X-Acto knife and straight edge around the perimeter, I set it up for laser cutting.

The instructions & layouts are images in PDF files, so it’s straightforward to import them into LightBurn and trace the outlines:

Ghost Truck – LightBurn vectors

Tracing produces short vectors and irregular curves:

Ghost Truck – LightBurn pre-optimize

The Optimize Shapes tool and a little manual intervention clean things up:

Ghost Truck – LightBurn post-optimize

You must manually add any cuts buried in the pattern, as in the Trailer Wheels parts shown above, so pay attention to the instructions.

Use the Move Laser tool to put the laser head at an obvious point on the layout, then skootch the printed page (in a Letter size fixture) to put that point under the beam. Repeat for another point, iterate until satisfied, then Fire The Laser:

Ghost Truck – cutout overview

Some irregularities peek around the edges:

Ghost Truck – cutout detail

On the whole, it’s much better than I could do with a knife.

Repeat for the other seven pages of parts:

Ghost Truck – Assembly

With some diligence I may have it ready for All Hallows Eve …

2026-04-17
Cheap HD USB Camera: Base Disassembly
A brace of cheap HD USB cameras may improve the scenery around here during video meetings. They were $16, marked down from an absurd $130:

HD USB Camera price history

Some poor schlubs certainly dropped more than twice the price of a Genuine Logitech camera on these critters, but a nearly total lack of demand must have had some effect.

They do take their stylin’ cues from Logitech, although the speckled pattern on a shiny plastic sheet is amusing:

HD USB Camera – styling vs Logitech C920

Unsurprisingly, the lens is fixed / manual focus. What looked like focus rings were in different positions on the two cameras:

HD USB Camera – lens focus notches

It turns out the rings were not glued in place, perhaps because they have absolutely no effect on the camera’s focus. Maybe there’s another camera model where they rotate the lens in a threaded socket, but this ain’t that.

The front panel has three pores:
- A red Power LED is always on when it’s plugged in
- A green On the air LED lights up when the camera is selected; I have no idea what the WiFi-ish glyph is supposed to represent
- The “advanced noise canceling microphone” sits behind a pore offscreen left; the claim seems dubious.
Because these may go into smaller spaces, I dismantled the base to see what was involved. Most of the screws lie underneath thin foam sheets:

HD USB Camera – ball mount interior

The lower plate has a tripod mount and a folding bracket:

HD USB Camera – baseplate interior

The camera body has a ball mount with a few degrees of movment:

HD USB Camera – ball mount detail

Reassembled and stuck inside the laser cabinet with some good double-sided foam tape, it definitely produces a better image than the previous camera:

Platform camera view

Whatever noise cancellation the mic may provide is irrelevant in there: nobody’s listening.
2026-02-17