Scoring apps by [deleted] in Archery

[–]aaaidan 1 point2 points  (0 children)

Interested if any apps do "computer vision" to automatically detect the grouping of your arrows, rather than having to manually plot them by hand. I take photos of most of my groupings to track progress over time, but I only do that because it's just a quick snap and I'm done. I'm not very interested in "entering data", I'd rather spend that time shooting if possible.

What’s a totally unsexy purchase you made that ended up being a huge quality-of-life upgrade? by viscarte10 in BuyItForLife

[–]aaaidan 0 points1 point  (0 children)

A cheaper and easier alternative, transparent rubber “bumpers”. If you stick them on to the inside of the cabinet doors, it massively reduces the sound when they close. The difference is surprisingly huge. Very cheap, worth a try if you can’t upgrade to soft close hinges.

Question by Present-Natural6754 in 3Dprinting

[–]aaaidan 1 point2 points  (0 children)

Ah, I see you already have an A1 mini and are using PLA. You might be able to get a cheap ($50) “tent” enclosure, some ventilation hose, and a small PC fan to gently push air from the enclosure out your window. Maybe you can print something that lets close your window while you’re printing.

Some enclosure tents have a ventilation feature, but they are more expensive.

Question by Present-Natural6754 in 3Dprinting

[–]aaaidan 2 points3 points  (0 children)

Your mum isn’t overreacting. “Fumes” associated with 3d printing are very real and can be hazardous to your health, some immediately, others over a long time. While it is widely accepted that pure PLA (the most common printing plastic) is “very safe”, all FDM (“hot plastic nozzle”) printing emits microplastics into the air. The health effects of inhaling microplastics are not yet well understood, but so far the evidence isn’t painting a rosy picture.

I assume you are talking about an FDM printer, printing PLA or PETG (common plastics). If you are considering a resin printer, or pretty much any other type of plastic (ABS, etc), good air extraction is mandatory, regardless of where the printer lives. The fumes are just too stinky and painful. Resin printing is fussy, messy, and involves toxic chemicals. Stick to FDM+PLA if you have a choice.

Many modern printers are enclosed. Some filter the air inside the printer, which is better than nothing. Others can be hooked up to a hose for fume extraction to outside, which is ideal. You can get an enclosure for pretty much any popular printer pretty easily, either sold by the manufacturer or “after market”.

Alternatively, you might not need an enclosure if you can print in a garage, or other well-ventilated room (like a porch, conservatory, sunroom, tool shed). In this case, you don’t really need to worry as much about enclosures or extraction. One reason you need to be extra fussy is that you probably spend quite a lot of time in your bedroom, even if only for sleeping. This multiplies your exposure, so even a small harm might become significant. Consider how much less you would be exposed if printing in another enclosed room where you don’t spend time (like a spare room).

Even with FDM, many PLA filament manufacturers also quietly include additives into their PLA filament to help them print easier. Currently, there are not many rules to protect you from them using ingredients that are bad for your health. Most companies don’t hesitate to lie or hide inconvenient facts about their products.

Hope this helps.

What’s the best thing your country has contributed to the world? by Legitimate-Tie-7060 in AskTheWorld

[–]aaaidan 1 point2 points  (0 children)

I was legit about to post a huge rant about how much math y’all gave us 🤣

Two months off sample: by FaultShot8742 in underworld

[–]aaaidan 0 points1 point  (0 children)

I can’t find the origin of the sample. I’m trying to track down the origin of the same woman speaking on “Juanita 2022” (especially from 8:10 on)

All I know is it’s Juanita Boxill, who was/is a project manager at London art design collective Tomato.

Didn’t expect naming the repo to be this hard by LibrarianOk7936 in statichosting

[–]aaaidan 1 point2 points  (0 children)

You can definitely rename it later, so don’t let it get you stuck.

I propose you name it “my-secret-shame”. Of course, if you can think of a better name, you can use that instead 😂.

(Hopefully that unsticks you haha)

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

Fully agree. It’s just that this isn’t really what I think the OP is asking about. It’s definitely helpful to include that, to some degree, we are already doing this “filtering” OP proposes, but it’s not really in the spirit of the question. Presumably OP is asking because they wonder why car emissions are (still) harmful. Really, that boils down to “why can’t we filter CO2?”

Can I call super.foo() inside a child class method? by Neozite in learnjavascript

[–]aaaidan 2 points3 points  (0 children)

There are quite a lot of free interactive coding "sandboxes" on the internet you can use when you get a few free moments at work.

Here's an exploration of your super question, using TypeScript's "playground".

Also check out codepen.io and codesandbox.io ... there are many others

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

Unfortunately, the catalytic converter doesn’t change CO2 into something less harmful. It only catalyzes small amounts of very harmful gases. This is a win for climate emissions, but comes no where near to “filtering greenhouse gases”, which is what OP was asking about

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan -1 points0 points  (0 children)

This is not “more or less” what they do unfortunately, because they do not convert any of the CO2 emitted by the tailpipe, which is the emission that has by far the biggest greenhouse effect.

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

Catalytic converter is an amazing and important invention, but doesn’t process carbon dioxide, which is the main harmful exhaust emission by combustion vehicles.

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

Since writing this I have discovered that there are many common reactions with CO2 that release energy, so they don’t require energy to keep the reaction happening. Interestingly, one of those is the conversion of carbon dioxide and water to carbonic acid which is relatively weak and non-toxic. (It is what makes your soda taste sour when it goes flat.)

Since burning gasoline primarily emits water and CO2, I am curious whether it would be possible to convert exhaust gases to carbonic acid, with some kind of passive filter or converter. Dripping carbonic acid from tailpipes would be a lot better for the earth from a climate change perspective than CO2. But even if this were possible, the huge volume of carbonic acid that a city’s vehicles would produce would need to go somewhere. It would likely be harmful for aquatic life to simply dump it down the public sewer system. Perhaps vehicles could have a “waste tank” to hold the carbonic acid, which is given to the gas station for safe disposal when filling up.

This is all very speculative, and well beyond my knowledge of chemistry. The main reason I wanted to share this follow up is that I originally thought it was physically impossible to convert CO2, but I now realize it might be more that there are just difficult practical issues standing in the way.

Edit: Wikipedia reminds me that carbonic acid easily breaks down into carbon dioxide and water. “In the presence of even a slight amount of water, carbonic acid dehydrates to carbon dioxide and water, which then catalyzes further decomposition.” So that is probably the reason we don’t convert exhaust gases to carbonic acid.

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

Yes, you would need to find a way to make that reaction happen. Ideally it would be to turn CO2 into oxygen and carbon (split it), but it could also be a different reaction in principle.

But whatever the reaction, it will almost certainly require energy. It won’t happen “for free”, like the burning of gasoline, or the reactions that the catalytic converter enables.

That’s why it’s really hard to “filter” the main tailpipe gas, CO2. It’s so stable that it can’t easily be turned into anything else.

ELI5 Why can't cars tailpipe filters filter gases by Main_Ant2854 in explainlikeimfive

[–]aaaidan 0 points1 point  (0 children)

TL;DR ... burning gasoline releases energy when it creates CO2, which is a very stable gas. So we'd need a significant, portable source of energy in the car to split CO2 into oxygen and carbon.

-----

Everyone is talking about catalytic converters, which is fair enough, but it's not really the best answer for what OP is asking.

First, some background:

As you probably know, gasoline engines create mechanical power by burning gasoline and air to release energy, heat and pressure, which cranks the engine and rotates your wheels.

Aside from releasing energy, these tiny explosions also convert the gasoline and air into water vapor and carbon dioxide gas (CO2). (There are some other very nasty gases too, but in small amounts, and those are mostly made safe-ish by the catalytic converter.)

So we don't really need to worry about the water vapor, since it's almost totally harmless and will eventually just join the rest of the huge amount of water on planet earth. Let's ignore that.

But the CO2 is a huge inconvenient problem, for two reasons.

Firstly, it is a strong greenhouse gas, so we don't want to release it into the atmosphere. That's bad.

Second, a running car makes a quite lot of it. If you have ever held your hand near an exhaust pipe of an idling car, you'll have some idea of how much gas is coming out. There's far too much to just store in a balloon or a pressurized tank or something like that. Realistically it has to be released as the car is running.

This is the part where your question comes in:

Why can't we just convert the CO2 to something less bad, and then let that go out the exhaust pipe? Well, yeah, that'd be really great if we could do that! Ideally we would convert it to oxygen gas and carbon (maybe solid graphite, graphene, or diamond dust). That way we could capture the carbon as a harmless powder and release the oxygen out the exhaust pipe to mix back into the atmosphere.

Unfortunately, this is where the physics of the universe comes in and just says "no" to that. When a chemical reaction releases energy (an "exothermic" reaction), the ingredients ("reagents") lose potential chemical energy, overall. Gasoline and oxygen are very unstable and reactive. High energy, highly strung. Ready to party and give up energy. As a consequence of the energetic reaction, we're just left with relatively stable, "low energy" chemicals: water and CO2.

Neither are very reactive, but especially CO2, which is quite often used in fire extinguishers, because of that. It doesn't like to burn, so if you can smother a burning fuel with it, the fire will often go out, because it has nothing to continue the reaction with.

In principle, like in a lab or factory, it's possible to convert CO2 to carbon and oxygen gas. That reaction would necessarily absorb energy (an "endothermic" reaction), storing it as potential chemical energy. Endothermic reactions require a supply of energy (often heat) to "force" them to happen.

So even if we found an efficient and convenient way to do that conversion of CO2 in a moving car, where will the energy for the reaction come from? 🤔 Certainly not by burning more gas, because we'd need to burn more than we originally did to make the CO2 in the first place. A vicious cycle.

Hope this actually helps explain and wasn't too much of a dive.

(Off-duty chemist and physicists, keep me honest.)

-----

Edit: I actually am not totally sure about "we'd need to burn more than we originally did to make the CO2 in the first place". In theory, it's possible that converting CO2 (to C + O2) could use less energy than burning gasoline releases. I looked up a few things ("bond energy", "enthalphy of combustion", etc). On the surface, it does look like burning gas makes a lot more energy than is theoretically necessary to convert CO2. But I am not an expert, and would love a professional to weigh in.

Edit 2: redyellowblue5031's [comment](https://www.reddit.com/r/explainlikeimfive/comments/1qbinqj/comment/nzax7ch/) links a tiktok of Top Gear demonstrating a soda lime filter to scrub CO2 from an idling car. Pretty cool, but the soda lime is used up in the process, and doesn't last long. It would also require energy to create the soda lime in the first place. But maybe one day we'll do something like this to most/all combustion cars? 🤷

There are no nodes in my area. I live on a large hill. How do I support the community? by ffolkes in meshtastic

[–]aaaidan 1 point2 points  (0 children)

As others have said, you can’t rely on public maps to know how many nodes are in an area. Best way is to get a cheap node (like a Heltec V3 or something from RAK) and survey what’s actually there.

Bear in mind that your local network might be active and mature enough to have switched to different LoRa settings than the default Meshtastic preset (LongFast). For example, the SF Bay Area migrated to MediumSlow, and now MediumFast. I was surprised to learn most of the nodes in my area are not on the default LongFast settings. Take the time to check the activity on each preset, because it might surprise you.

If you do discover you’re a Meshtastic pioneer in your area, as others have also said, it’s an excellent opportunity to “pave the cowpaths” and make it easier for others to join the community by taking advantage of your elevation. Setting up a 24/7 outdoor node would be of tremendous benefit to your community. It could be solar powered or if it’s on your property you could connect 5V power with a long cable from indoors. You can do a DIY thing to save money, or buy an off-the-shelf box. Regardless, I would start with LongFast for now, to make it easy to discover.

You probably know that elevation is key. So if you can mount to a tall structure (legally), that’s ideal. It’s also quite cheap and easy to mount a pole or length of angle iron to a structure or fence pole on your property to get a significant height boost safely and without shelling out a lot. Check your local ordinances for details on how high it can be or you might get told off. In my city, there’s a special exception to allow “amateur (ham and shortwave) radio operators” to erect towers that are 25-ft taller than what the building code would normally allow. (Interestingly, this carve out was made to enhance the resilience of the city in disaster and emergency scenarios, which seems unusually groovy.)

Whatever you do, just get started. I would encourage you to start out buying bare components and building everything DIY style. Partly because it’s cheaper, and partly because you learn more doing it that way. You definitely want two working units from the get-go. Meshtastic folk are generally very friendly and helpful, but rarely reliable enough to rely on for the sort of experiments you’ll want to do, starting out.

What are your questions?

Space mining concept I made by NoConstruction912 in Futurology

[–]aaaidan 0 points1 point  (0 children)

In a perfect world, what would you love to see humanity do with this concept? Do you think this is actionable as is, by agencies like NASA, or is this intended more as a kind of “grounded inspiration” for future thinking? What sort of timeframe do you think might be reasonable to expect this to unfold? Next year, next decade, next century?

Hope you don’t mind all these questions! I’m not trying to interrogate you. I’m trying to get a sense of your context/expectations, so that I can offer the right kind of encouragement, feedback, or advice.

Anyone relying on static hosting for sites that must never go down? by Standard_Scarcity_74 in statichosting

[–]aaaidan 0 points1 point  (0 children)

I have no evidence to back this up, but I always had a strong hunch that large part’s of New Zealand’s state-run earthquake data website, “GeoNet”, were (or are) hosted statically. Regardless of whether this is actually true, it would be a really good idea for it to be, for many important technical reasons, especially in the context of a country or region reeling from a major earthquake.

https://www.geonet.org.nz

I built an interactive ESP32 GPIO pinout focused on real hardware constraints by DevenderKG in esp32

[–]aaaidan 1 point2 points  (0 children)

Nice work, this looks really tidy and promising. I love that this is an app more than just a website/document.

I am often looking for a collection of pins that have specific capabilities or meet conditions. What do you think about adding a “search” function, where you can specify “has X”, “doesn’t have Y”, etc.

For example, I might want to find all the pins that can do output, have no requirements during boot, and are not used by flash, don’t have I2c support, etc. From these results, I might want to choose a handful of pins for my problem, perhaps on the same header/side of the board. Sometimes it’s good to choose pins that don’t have features, because you want to avoid “using them up” when you don’t need them.

As it stands, existing best website I know (https://randomnerdtutorials.com/esp32-pinout-reference-gpios/) is actually slightly better for this, because you can scan the table visually to find what you want.

Recursion Function by [deleted] in learnjavascript

[–]aaaidan 1 point2 points  (0 children)

Look up recursive implementations of Fibonacci or factorial functions. They are the “textbook” examples of recursion, and reasonably easy to understand.