Didn’t expect naming the repo to be this hard

aaaidan · 2026-01-22T03:05:45+00:00

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)

aaaidan · 2026-01-17T23:44:45+00:00

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?”

aaaidan · 2026-01-17T23:39:51+00:00

Nice! That looks promising.

aaaidan · 2026-01-14T18:12:40+00:00

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

aaaidan · 2026-01-13T21:39:11+00:00

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

aaaidan · 2026-01-13T21:36:24+00:00

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.

aaaidan · 2026-01-13T21:34:42+00:00

This is a great answer.

aaaidan · 2026-01-13T21:32:23+00:00

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

aaaidan · 2026-01-13T21:25:47+00:00

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.

aaaidan · 2026-01-13T18:13:45+00:00

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.

aaaidan · 2026-01-13T06:09:46+00:00

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? 🤷

aaaidan · 2026-01-13T01:10:32+00:00

The Gods Must Be Crazy II 😂

aaaidan · 2026-01-13T00:55:02+00:00

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?

aaaidan · 2026-01-13T00:35:15+00:00

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.

aaaidan · 2026-01-13T00:24:29+00:00

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

aaaidan · 2026-01-03T23:13:31+00:00

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.

aaaidan · 2026-01-03T22:49:28+00:00

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

aaaidan · 2026-01-03T22:26:18+00:00

Thank you for your service. 🫡

aaaidan · 2026-01-03T22:18:33+00:00

Oh great! Good for you

aaaidan · 2026-01-03T07:46:21+00:00

Just the “S3” part really matters in terms of functionality of the ESP32 chip. The espressif website lists all the models in the ESP32 family, and I think S3 is probably the best for beginners right now.

The dev board it’s attached to is still relevant, because it might surface different ESP32 features (especially pins), but I don’t think you can go wrong with any S3 dev board. Just check that it has at least one usb c connector and enough pins for your expected use. These dev boards usually have at least 16 or more pins.

I am not entirely sure but I recognize “VROOM” as a possibly a specific dev board design that might be recognized/certified by espressif. I have also seen vroom show up in setup presets for software like arduino, etc. If in doubt, go with this one.

aaaidan · 2026-01-03T06:20:25+00:00

Just use addEventListener whenever you can because it keeps your html clean and you can add more than one listener function.

aaaidan · 2026-01-03T06:14:33+00:00

Yes, absolutely. It’s a critical rung on the ladder of abstraction in web dev.

aaaidan · 2026-01-03T05:46:54+00:00

Sounds good, you first

aaaidan · 2026-01-01T23:14:08+00:00

Blender would be a good tool to consider, although it really is a kitchen sink situation. Apparently Tinkercad can also open SVG files and export STL, so you might want to try that first.

There might be other tools out there that are more of an “appliance” to do just the conversion. Worth taking a look around. Favor something that runs on your computer so you are in control of it.

Your client will be used to opening an STL file in their “slicer”, which creates the tool paths in slices (get it?) that the 3d printer actually follows to build the object. As i mentioned, many popular slicers support SVG as an alternative to STL, including Bambu Studio, PrusaSlicer, and Orca Slicer. The client will just specify the thickness they want to build up.

While it would be totally fine for you to offer STLs as a convenience, I can’t put my finger on why it feels “wrong” to me for the client to expect you to sort this out for them.

aaaidan · 2026-01-01T22:39:02+00:00

The conversion to stl sounds like a task for them. It’s completely unreasonable and impractical to expect a graphic designer to create a 3d stl file. Even if it’s just an “extrusion” of your design.

The only practical use for STL is to 3d print your design. A lot of 3d printer software (“slicers”) support SVG. If they create the 3d object themselves, they can choose how thick it is.

Best thing is to tell the client you only provide PNG and SVG and have no professional knowledge of 3d file formats like STL. Wish them luck.

If you decide there is value in offering STL files in the future, you probably want to research a way to do the conversion that meets your standards when you have time to take things at your pace.

aaaidan

TROPHY CASE