Linux gamer, retired aviator, profanity enthusiast

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Joined 2 years ago
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Cake day: June 20th, 2023

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  • There’s a LOT of e. coli up your ass.

    Put more delicately, you are a great big multicellular eukaryote, each of your cells has (or had, in the case of red blood cells) an inner chamber called the nucleus, and you’re full of mitochondria and other organelles. Your body is covered and filled with other organisms, many of them simple, tiny little single cell prokaryotes which make a living helping their gigantic, complicated host function. Like all the bacteria in your intestines that help you digest food. Their cells outnumber yours by a wide margin.


  • So, here’s a lesson from the flight physiology chapter of the private pilot syllabus:

    Your vision is a lot worse than you think it is. You probably conceptualize your eye as similar to a digital camera, there’s a lens that focuses light on a sensor made up of an array of light sensitive cells, and that the edge of that array is as densely packed as the center. This is the case for a camera, but not for your eye.

    Each of your eyes has over 30 million photoreceptors called rods and cones.

    Rod cells come in one variety and are only really good for detecting presence or absence of light. They work well, or can work well, in very dim light, and they form the basis of your night vision. This is why in very dim conditions you might experience your vision in black and white.

    Cone cells are less sensitive to light requiring relatively bright light to function, and come in three varieties that respond the strongest to low, middle and high wavelengths of light, what we know as red, green and blue. By comparing the relative intensities of these wavelengths, we can derive color vision. They don’t work well in low light conditions.

    The sensor array in the back of your eye that contains these photosensitive cells, called the retina, is sparsely populated toward the edges and doesn’t have very good resolution. Try reading this sentence looking at it through the corner of your eye. It gets denser and denser, and the ratio of cones to rods increases, until you reach a tiny pit in the very center called the fovea.

    This is difficult to put into words but unless you’ve been blind since birth you’ll understand what I mean: You use your whole retina to “see.” You use your fovea to “look.” The detailed center of your vision, the spot where you are “looking” is drawn from the fovea through the center of the lens out into the world. When you are looking at something, you are pointing your fovea(s) at it.

    There are no rod cells in your fovea, only cones. So you have very high resolution color day vision, but next to no night vision, with your fovea.

    This is why things like dim stars in the night sky can be more easily seen with your peripheral vision than your central vision. Your central vision does not have the cells to see well in the dark. It’s not in the anatomy.

    We teach this to pilots because distant lights the pilot is using to navigate by, avoiding collisions with obstacles or other aircraft, might be dim enough that the night adjusted eye can’t actually see it with the center vision but can with peripheral vision.

    The same chapter teaches about the “hole” through which the optic nerve passes and how that blind spot is capable of hiding something like another airplane from you, which is why you look around and don’t just stare out the windshield. It’s not often a problem because most of the time one eye can see into the other’s blind spot, but it’s useful to know that about your vision.

    Each cell will detect some light, undergo a chemical process that fires an adjacent neuron, and then take a very brief moment to reset to be ready to do it again. Each cell is doing this independently, so your eyes don’t have a “frame rate” the way a camera does, but a flickering light begins to look continuous to humans at a rate of about 18 cycles per second and no flicker can be detected somewhere around 40.

    Your occipital lobe takes in this choppy inconsistent resolution broken up mess of visual information passed to it via your optic nerves, does some RTX DLSS 4k HDR10 shit to it and outputs the continuous and smooth color 3D picture you consciousness experiences as “vision.”

    AND THEN ON TOP OF THAT your brain does optical everything recognition. You can look at millions of different objects - the letters of the alphabet, tools, toys, people, individual people’s faces, leaves, flowers, creatures, stars, planets, moons, your own hands, and recognize what they are with astonishing speed and accuracy.

    It’s what scientists call the hellawhack shiznit that happens inside your brizzle.




  • Some of this I think still goes for hobbyists if they plan to buy the printer as a kit. The first (of like, eight) Prusas I built I had a hell of a time assembling the extruder mech because it’s not designed to be easy or sane to assemble, I still pinched wires, not bad enough to break anything but still. And I had built several 3D printers and a couple laser engravers prior to this.

    And that PINDA probe mount is still hilariously delicate.

    As a hobbyist machine that will spend most of its time powered off, they’re fine. For their gantry mechanism and the 8-bit control board, they’re surprisingly high quality if slightly slow printers.

    Oh there’s another thing: The Prusa community is in the bad habit of sharing G-Code rather than STLs, because everyone everywhere has the same printer, right?

    My personal printer is still my first manually leveled Folger 2020 i3 with some customization of mine, and I don’t need another.


  • 1840s, actually. The patent was granted to a Scottish man named Alexander Bain.

    First thing’s first, the telegraph. An electric circuit which can be energized or not energized at the push of a button called a telegraph key. At the other end is a solenoid which is spring loaded up, and an electromagnet on the circuit pulls down when the line is energized. Originally this was supposed to cut into paper tape to “print” the morse code message, but telegraphers quickly learned how to hear the letters in the clicks, a good telegrapher just…hears words. So they did away with the tape.

    Morse code telegraphs require a single circuit to transmit an on/off keying message, the following aparatus uses five:

    If I understand this right, the message would be written on non-conductive paper with conductive ink, and then wound around a cylinder that featured a whole bunch of insulated conductive pins, each kind of forming a “pixel.” A mechanical probe would check each one of those pins in turn, each pin in a row, and then shifting to the next row at the end. if it was conductive it meant there was ink there so click. So it would perform a raster scan. At the other end was paper that was coated with an electrosensitive material that would darken with the application of current, so at each pixel if the conductive ink on the original completed a circuit, current would be applied at that pixel on the copy, producing a low quality probably unusable copy. It was difficult to get them truly in sync plus it would have been hilariously low resolution. But it did somewhat function.


  • I had a side gig as the printer mechanic for a small company that 3D printed bracketry for their product. They used both genuine and “knockoff” (open source ftw) Prusa Mk3s. I’d kinda like to staple Josef Prusa’s foreskin to the ceiling. I think it would make him have better ideas than the extruder-and-hot-end-assembly that those machines currently have. Deal breaking issues I’ve had with them in service:

    • Nothing is connectorized at the business end. If you need to replace either of the two fans, the extruder motor, the PINDA probe, the temperature sensor, the heater cartridge, you have to partially disassemble the extruder mechanism and unwrap the wiring harness. The filament runout sensor is connectorized at the tiny little board, but…

    • The wiring harness passes through a hole in the back of the carriage plate and most of the wires have to fit into one of two little slots as the extruder mechanism is attached to the carriage. It’s really easy to pinch or sever wires like this, and it means you can’t replace a broken fan or something without partial disassembly.

    • The PINDA probe mount is about 3 planck lengths thick. It’s subject to some load from the thickness of the PINDA probe’s cable, it’s rather near the hot end and the heat plate, so I’ve seen them warp or break under continuous use. And it’s built into a foundational part of the mechanism so it’s not a quick swap, it’s a 100% teardown and rebuild from scratch.

    • The whole thing is a demented sandwich with like 25 printed plastic parts. It’s a convoluted thing to work on, even if it’s not printed in gloss black so you can make out the shape of everything. But they print it in gloss black.

    • It’s not designed to be built up as an assembly that can be easily and quickly attached and detached from the printer. In service, this makes it impossible to have a spare extruder assembly built up so when you get “Number 3 needs a new nozzle” you can swap in the spare assembly, return the machine to service, and then work on the part at your leisure. No, the production manager is breathing down your neck with a machine in many pieces. Hand me my stapler, I just want to talk to him.

    • Those goddamn pressed in square nuts. If you want to re-use the hardware because one of the many plastic pieces partially broke in a way that means you HAVE to replace it, re-using the hardware is just one more jumper cable to the cornea.

    It’s not specific to the Extruder mechanism, but because nothing is connectorized at the business end, you end up having to open the main board’s enclosure and dealing with shit in there, and there isn’t room. It’s turned the wrong way; the connectors and shit should be on the OUTSIDE of the printer so you could get to them easier and most of the cover should hinge or bolt off.

    For an 8-bit AVR-based Mendel pattern machine they work surprisingly well when they’re in good shape but they are a PAIN IN THE TAINT to keep running in a production environment. I have the skills to do better than this but I’m not doing it for free.







  • Captain Aggravated@sh.itjust.worksto196@lemmy.blahaj.zoneCartridge rule
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    2 days ago

    You oculdn’t play original Black & White games on GBA though, could you? Even though the GBA slot was designed to take original games?

    They’ve done a lot of that kind of thing; the original GameBoy cartridges had chamfered edges and a corner notched, GBC games (the clear cart “GBC-Only” ones, not the Black “GB games that will have color if you run them on a GBC” games) lacked those chamfers so they wouldn’t even begin to slide in, plus the “Gameboy Color” logo area was convex instead of concave, and the power switch notch wasn’t there.

    Gameboy Advance cartridges had a similar cross-section to GBC games but were shorter and had a flare at the top so you couldn’t insert one into a Gameboy Color. I don’t think a GBA could play original GB games even though they would physically attach. The GBA could play GBC games, they would stand a bit more than an inch proud of the cartridge slot if you did though.

    There was a GBA Mini, which I think dropped compatibility with GBC games? And I don’t know about the clamshell Advance, the Advance SP was it called?

    DS games were a very different shape, they were closer to SD cards. Early models of the DS had GBA cartridge ports and would accept GBA games only, not even Color ones. That port was also used for some peripherals for DS games. It was deprecated in later models, and then they added the tab on the side at some point so that newer DS games couldn’t fit in older DSes…I’m the only human outside of Sentinel Island to not own a Nintendo DS (even Jesus had one) so I have only a vague idea of what a DSi was compared to a 3DS.