I'm a technical kinda guy, doing technical kinda stuff.

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  • 26 Comments
Joined 9 months ago
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Cake day: September 27th, 2023

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  • Dave.@aussie.zonetohistoryCounter "Sit In" Protestor in 1960
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    edit-2
    6 months ago

    It's black and white because a lot of the photography around the civil rights movement was for newspapers.

    So, there are three chief advantages of black and white film:

    Firstly, newsprint means colour is superfluous because newsprint is black and white with a halftone process to get shades of grey.

    Secondly, black and white film was (and still is) a lot more sensitive and forgiving of lighting conditions than colour film, especially colour film in the '60s. That's pretty important when you're in a crowd trying to get a photo of something in a hurry. It means you can use a smaller aperture which gives you a greater depth of field, which makes for nice snaps to capture a whole scene. You can also up the shutter speed to give crisp photos with no motion blur.

    Finally, black and white film has a quick and easy development process. So you can get your prints in and out of the newspaper darkroom pronto, and you can manually pump the lighting and contrast during the development process to make a mediocre photo good enough for the evening paper.




  • I remember helping a teacher at school who had installed a CopyIIPc card on one of our computers. They used it to make everyday copies of the master disks of the copy protected educational software we used in our room full of Sperry IBM compatible PCs.

    The card went in between the floppy controller and the drive and could do a pretty good job at duplicating all the physical copy protection tricks of the time.

    They copied a lot of stuff, not for pirating reasons but simply because they were literally 5 1/4" floppy disks back then and school kids were not kind to them. Either it was simply jamming them into the drives, or touching the exposed disc surface, or chucking them around the room, those disks didn't last long.




  • Dave.@aussie.zonetoScience Memes@mander.xyzbro pls
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    8 months ago

    But look how fast we can make those little fuckers go!

    It's just like slot car racing, round and round, but.... you know.... faster. And yeah, it's more expensive than a regular slot car track, I guess. But still, those particles will beat any slot car you care to pick! So there's that. Welllll not those fancy slot cars with them high performance motors, I mean, that's a completely different ballgame there, we can't compete with that.

    But still, those particles whizzing around, it's gonna be pretty cool. I reckon we should do it.

    So anyway, thank you for reading my financial proposal for the SuperLHC.




  • The issue is when dynamic range exceeds the buffer you have in your viewing environment.

    So you can easily mix a movie with 45dB dynamic range, and you have been able to distribute that to the masses for 30+ years. And so you can also accurately and easily portray a stage whisper at 50dB and then have an action sequence peaking at a modest 95dB in a relatively soundproofed cinema with 30 speakers and a couple of thousand watts behind it.

    But for me to hear that movie on my TV in my 65dB environment means the next action sequence is now 110dB, well past the capability of my TV speakers to accurately reproduce, and also well past the level where I would consider it to be fucking loud.

    If you're mixing audio for a home release you need to compress your dynamic range to 30dB or so to suit. The number of viewers that have a sound system and a viewing environment that can comfortably allow 45dB of range is very, very, small, and if those people want to complain about the lack of dynamic range, they can get themselves an expander and go nuts.




  • Eh? You've got your thoughts backwards on the pins.

    The inside of a USB C socket is simply a central tang. The inside of a USB C plug has the flex pins that grip said tang and provide the electrical connection. The USB plug, on the cable, is designed to wear out before the socket and it's easily replaced.

    The issue however is that some manufacturers skimp on the mechanical mounting of the socket on their device and flexing of the connector + socket damages its connection to the board.

    Funnily enough, lightning connectors are designed the other way around with the components that wear out inside the expensive device. How strange.....But that's coming from a company that doesn't even want to make a robust covering for the wires in their cables.


  • It's generic foam pipe insulation, approximately 3/4" thick.Originally there was also a 3-4 meter section of pipework from the collector output to inside the roof that was completely uninsulated, I've gotten that sorted.

    I bought the place a couple of years ago and after replacing the seized circulating pump early last year I was pretty disappointed with the system's performance.

    At that point I put onewire sensors on the tank and lines on the ground level and measured it for a few months and didn't see much heating at all from the collector.

    I couldn't get to the collectors for a long time, not having a three storey ladder, but I got suspicious after sunny + windy days resulted in very little heating. Finally got up there about three months ago to discover that bare section of pipe and insulated that.

    Collector temperature I haven't measured using the original analog sensor yet, I just let the original controller do its thing to get a baseline. But currently in a "warm" Australian spring the maximum outlet temperature at ground level is a brief peak of about 65 degrees C at around 1pm. Going off the circulation rate of the pump it's probably 40 litres of water at that temp before it starts dropping back down in the afternoon.

    Insulating that bare section of pipe improved performance but it's still not fantastic, so now it's time to drive the pump with my own algorithm and see if I can improve things.


  • At my latitude, never below 8 or 9 degrees C in winter. Maximum temperature is about 35 or 36 degrees C in summer.

    Older systems here were simple thermosyphon designs on the roof with the holding tank closely coupled directly above the collectors and they were quite effective.

    My system has a 330 litre mains pressure hot water tank, with the usual cold and hot fittings bottom and top. There is a third inlet about 1/3rd of the way up the tank, and a little bit above that is a heater element and a controlling thermostat. The lower third of the tank is circulated out via the cold inlet and up through the collector by the pump, which can do about 300 litres an hour. Hot water returns from the collector at the 1/3rd location, and rises to the top of the tank via stratification. The copper pipes to and from the collectors are 1/2" and are insulated, but their surface area to volume ratio is quite large and heat is easily lost over the 15 or so metres of pipework.

    On sunny days I can see the inlet temperature at the bottom of the tank slowly rise from approx 20-25 degrees C to 30-35 degrees C as the bottom third circulates, the hotter water rises to the top to give the small temperature rise I can see at the top of the tank and the warm water layer slowly lowers towards the bottom of the tank.

    Essentially I want a higher temperature returned to the tank, which I suspect can rather paradoxically be done by increasing the circulation rate when running the pump, peaking the collector temperature higher with the pump off then dumping that back to the tank rapidly, rather than the current controllers method of pulsing the pump and slowly circulating it to maintain a moderate collector temperature and losing the heat in the lines.

    I have the service manual for the controller and it mentions frost protection, where it will circulate warmer water back to the collectors in low temperatures, but this would be insufficient for your colder climate.

    At some stage I would also like to control the heater element, it runs on an off peak circuit which is switched by the electricity company when it suits them, so it is cheaper to run. It also means that it regularly "tops up" the top 2/3rds of the tank temperature, which negates the solar contribution a fair bit. I would like to be able to disable that top up if the system can sense adequate heating from the collectors, but that requires switching control to a 3kW element, and something I will leave alone for now.


  • Cars can slow down much, much faster than they can speed up. Look at any 0-60 and 60-0 times in car reviews.

    If there is any situation when you can see a potential accident and speeding up "saves you", then you also have sufficient time to slow down and let the other vehicle pass in front of you.

    If you are that close that rapidly slowing down doesn't help, your reaction time plus the relatively slow rate of acceleration means that speeding up won't help either.

    (Disclaimer: this doesn't work with trains.)



  • I tried a few food delivery mobs a couple of times, they were consistently shit at actually doing the thing they say they do, and they were expensive.

    So now if I want delivery, I find a local food joint that delivers the food themselves. If the place I want doesn't deliver , I get off my fat arse and get it myself. I find that also helps me decide if I really want it or not.


  • Dave.@aussie.zonetoBrisbane@aussie.zoneFellow pathway users.
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    8 months ago

    If you find something particularly bad, use the Snap-Send-Solve app to take a photo and push it off to council.

    They have a regular program where they go around and grind down lifted edges due to tree roots, etc, but they don't have eyes everywhere. If you point it out they'll put it on the list and it usually gets resolved in a few weeks.

    The app works for nearly all public facilities, eg I use a park where an entire string of pathway lights were out for ages. I took a photo with the app and sent it to off to Energex with a pole number and four or five days later it was sorted. Don't know if it was actually because of my action but I'll believe it haha.

    https://www.snapsendsolve.com/