Thanks for explaining. Yeah, I’m sure it’s pretty much alright with your circuit breaker. I suppose your main concern for having the fuses is so that those relais can’t start a fire once the current is between 10A and 16A for too long. I was just thinking about failure modes. And having something fail, the fuse blow and then half the board still has 230V feels a bit strange. But I guess it’s alright. I’m not an expert anyways.

I saw those PCB mounted 5V power supplies coming up in ESP32-projects before. I always thought they were some cheap chinese stuff and you shouldn’t trust them. But if they have a proper fuse inside and do proper 5V… Maybe I need to change my mind and start digging deeper.

Idk about mixing 10A relais and 5A traces and connectors. Everytime I buy some shelly stuff, I just have a look at the print on the relais before I wire something up. That’d be wrong in case someone had made the traces smaller. But I guess you can just write 5A MAX on the pcb and everyone can see that, even if one day somebody else does some maintenance. In this case you obviously need a 5A fuse.

I’d agree with the tip of that ground plane is close to the high voltage part. And there’s still space left on the right.

The ULN2003A claims to have the flyback diodes and they’re connected. So you don’t need another set.

I’m not an electronic expert myself. But I don’t get why the fuses are the way they are. Most of the times I see boards having one fuse and when it’s blown, the whole board is separated from electricity. You’re kind of splitting it up 3 ways.

And the 5A of the fuses doesn’t match with the 10A rating of the relais or the 400W you wrote for the connectors. But I get that you have maybe 6 motors moving simultaneously.

(And why do you have the N trace to the connectors split in the middle and a whole other trace going all the way around? Is that to balance things when there’s much current going over that single trace? Or to match the 2 fuse design?)

I don’t know. You’re connecting the two batteries. The one that has more voltage will charge the battery with less voltage. And because it’s just a strip of copper between the two, without significant resistance, it’ll happen fast. The thing limiting current flow is probably the internal resistance of the battery itself. And for example alkaline batteries, you’re not supposed to charge them.

I haven’t tried what exactly happens. AA batteries aren’t as powerful as for example Li-Ion batteries. So you’ll probably be alright. Maybe in the worst case one battery gets hot and smells funny. But I don’t think this will cause a proper fire. If it’s only a bit, it’ll get a bit warm and you waste some energy, that’s probably it.

If you connect one in reverse I’m not so sure anymore. I once had a rechargeable battery that was connected in reverse get really really hot and bulge. Once you do things like this with Li-Ion rechargeable batteries, I think you’re in the realm of starting a fire.

I hope you know the consequences of having batteries in parallel? I mean, if they have different voltages you’ll get some current going between the batteries until they equalize. And the consequence of having one in reverse is probably also much worse than having them in series.

Well, there’s also turtles to program in Python (i think) and there is Scratch.

I guess there’s a real risk (…like 100%) that I overestimate the motivation students have

Definitely sounds like it. But a motivated teacher is a very good thing. Maybe you’re able to get that spark across to some of the students.

API-like to abstract away the low-level components

You can always have some extra assignments ready, just in case someone is curious and wants to do/know more. A room full of studens will have a mixed amount of knowledge, abilities and motivation anyways.

I’m most interested in resource-constrained embedded systems. I like the attiny10 a lot.

I also ate a few books and datasheets on the Atmel chips in my lifetime. Their design is well-thought-out and probably an excellent subject to learn the concepts about microcontrollers.

As of now I like the ESP32. It is ridiculously overpowered if you’re used to something like the ATtinies or old ATmegas. With (at least) 520kB of RAM, two cores that work at 240MHz (depending on variant) and very nice peripherals. Also WiFi connectivity is really useful. But it definitely adds to the fun if you programmed the more constrained (previous generation of) microcontrollers and know how spoiled you are and can feel like a supervillain wasting hundreds of kilobytes of memory deliberately. Or (ab)use some of the peripherals for things that wouldn’t be possible with the few timers available on the Atmel chips. Or do trigonometry at crazy frequencies for your robots, because you can handle 32bit floating point numbers. But I’d agree, that doesn’t teach you the same things if you can do floating point arithmetics for cheap and don’t know if calculating a square root is an easy or difficult thing to do. The STM chips also have nice peripherals. But I haven’t really fiddled around with those.

Definitely hope you’ll have fun being involved in that STEM program.

Well, kids / young people / students will surprise you anyways. No matter what you planned ahead. I think teaching this way just requires you to stay flexible and try things with the students and see what works. University students will benefit from a little challenge, but it shouldn’t be impossible and get them frustrated. I’ve never taught myself, but I bet it’s difficult to hit that balance.

Programming little robots is awesome, though. I think it’s on a whole other level to see robots move and do tasks, than to look at your screen and program something that changes a few pixels there. My university course was more related to embedded devices and closer to the electronics. It teaches you valuable lessons when forced to interact with some electronics, real-world physics, constrained resources and you need to get your maths right. Usually students are concerned with something like Java, learning object-oriented programming or handling some big frameworks. Or learning maths. And robotics teaches you to really pay attention, combine different skill-sets and do things without an easy route available.

Maybe it’s just me who likes electronics too much. But I’m sure the kind of motivation you get by watching a real robot move and it runs your code, is unique. And kind of universal. You can do this in pre-school or in university to spark their imagination and motivation.

Your task is a bit different. If you’re teaching something like simultaneous localization and mapping and the students also have to deal with all the robotics, sensors and real-word problems, this might be more of an ordeal for them than fun. Even dealing with noisy sensor values is a hassle until you get to grasp the bigger picture.

If you’re giving them access to an API, you can choose and adjust what kind of abstraction you’re providing them. Give them something high-level or have them do more work. You could prepare most of the implementation and adjust the level of detail while teaching. Maybe skip something and give them working code via your API so they can focus on the problem they’re actually supposed to learn. You can also do it the other way round. Let them start with all low level stuff handled for them and learn the big concepts. Then let them dig down and see what your API functions have abstracted away until then. This way around you won’t run out of time.

I’m sure including actual robotics is going to get them more motivated in contrast to running a simulation.

I think mecanum wheels slip quite a bit. So I’m not sure how effective those encoders are. But I’ve only ever tried 3d-printed ones. So I’m not super sure.

You’re sure your STEM students are ready to handle the LiDAR? Manage point clouds, do the arithmetic, path planning etc? We had a practical course with little robots. But they had 3 of those sharp distance sensors at the front and a bumper with a switch. This was enough to teach many concepts and also enough to implement for the students for something that was just a project and not a full time job. But I’m sure that depends on what exactly you want to teach…

And our robots hat the motor drivers (h-bridges) replaceable on socket terminals because every so often someone wasn’t very clever or didn’t listen in the lectures.

Thx. I think it’s a variant of the Kelvin water dropper

(Derek from Veritasium explains it here. At the end he explains how much energy is generated.)

Wow. Thanks for the link. Unfortunately this video isn’t very scientific. You don’t measure electrical energy in millivolts but in Jules (or watt-hours). Or in an experiment like this you would measure electrical charge (Coulomb) generated by a certain amount of water.

And I would expect the charge to come from the clouds or air or something. That would mean the water wheel shouldn’t generate any electricity in his experiment.

Measuring Voltage is kind of wrong. You also get a reading of a few hundred millivolts if you randomly stick your multimeter somewhere. Or take the probes in your hands and squeeze them. That also generates a few hundred millivolts. But it isn’t energy.

I’d love to see his experiments repeated in a bit more scientific way. And someone to figure out how to do that at scale. How to connect a square meter of those electrodes. And how to arrange them.

If you actually build something, make sure to document that in a blog with pictures or video for us. I kind of want to know if it’s really 50W per square meter of free energy in the rain drops.

I have aluminum foil and a spray can at home :-)

https://youtube.com/watch?v=S6oNxckjEiE

Depends on the use case. It is a very good idea to harvest small amounts of energy for example to use it in a calculator or a clock or a remote control or button or light switch. This way you never need to replace batteries or have them leak and destroy the thing.

Apart from that. There aren’t many use cases for those very small amounts of energy. You have to ask yourself what you’re going to use that small amount of energy for. Because batteries and wires are way cheaper. And they store amounts of energy you’d need 20 years of harvesting with equipment that costs a lot more. It just depends on the use case. And for little amounts of energy, the use-cases are severely limited.

You’re allowed to do this as a hobby, however ;-)

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This is a very pessimistic perspective.

Also poverty and hunger are lower than ever before (considering previous eras, and it’s not yet good). More and more people are getting education. Fairness towards women and minorities used to get better.

We’re having scientific advancements every day and can easily communicate with people around the globe, and it’s even cheap and available to many people. Some people think we’ll soon invent general artificial intelligence and maybe robots will do the unattractive labor for us. Some people (i’m not sure if i trust people like Elon Musk(?)) even say science is soon going to solve things like overpopulation and climate change. They want star trek to become true. Also medicine is getting better each day, we can cure more and more things and people need to suffer less and less. Maybe there is a cure for cancer coming up in the next decade.

Is it really on the decline? Are we having less or more wars than we used to have? Can we afford more or less stuff than our parents or grandparents did? I’m not sure… Things are a bit complicated and sometimes something gets worse while other things get better. Sometimes it’s for short or longer periods. I get what you mean and it’s a problem. And too many people around the world are suffering things we could have fixed by now. But this is only half of the story.

No. lemmy.ml used to be the biggest instance with the most communities originating there. (And the instance launched by the developers.) It has been the flagship instance. But it’s a thing of the past. Just have a look at the statistics. For example here or here. The biggest instance currently is lemmy.world with about 5 times the active users. And since the reddit exodus, most of the active communities have been opened on other instances.

I like my thinkpad. the keyboard is okay. i don’t use the touchpad. i can carry it everywhere, take it to the livingroom or kitchen or watch a movie in bed. Downside is: i’d like to have more storage and RAM.

because it takes a 1:1 copy of the picture and stores it

What makes you think that? This is wrong. Sure you can try and train a neuronal network to remember something exactly. But this would waste gigabytes of memory and lots of computing for some photo that you could just store on the smallest thumbdrive as a jpg and clone it with the digital precision, computers are made for. You don’t need a neural net for that. And once you start feeding it the third or fourth photo, the first one will deteriorate and it will become difficult to reproduce each of them exactly. I’m not an expert on machine learning, but i think the fact that floating point arithmetic has a certain, finite precision and we’re talking about statistics and hundreds of thousands to millions of pixels per photo makes it even more difficult to store things exactly.

Actually the way machine learning models work is: It has a look at lots of photos and each time adapts its weights a tiny bit. Nothing gets copied 1:1. A small amount if information is transferred from the item into the weights. And that is the way you want it to work to be useful. It should not memorise each of van gogh’s paintings 1:1 because this wouldn’t allow you to create a new fake van gogh. You want it to understand how van gogh’s style looks. You want it to learn concepts and store more abstract knowledge, that it can then apply to new tasks. I hope i explained this well enough. If machine learning worked the way you described, it would be nothing more than expensive storage. It could reproduce things 1:1 but you obviously can’t tell your thumbdrive or harddisk to create a Mona Lisa in a new, previously unseen way.

Just take for example Stable Diffusion and tell it to recreate the Mona Lisa. Maybe re-genrate a few times. You’ll see it doesn’t have the exact pixel values of the original image and you won’t be able to get a 1:1 copy. If you look at a few outputs, you’ll see it draws it from memory, with some variation. It also reproduces the painting being photographed from slightly different angles and with and without the golden frame around it. Once you tell it to draw it frowning or in anime style, you’ll see that the neural network has learned the names of facial expressions and painting styles, and which one is present in the Mona Lisa. So much that it can even swap them without effort.

And even if neural networks can remember things very precisely… What about people with eidetic memory? What about the painters in the 19th century who painted very photorealistic landscape images or small towns. Do we now say this isn’t original because they portrayed an existing village? No, of course it’s art and we’re happy we get to know exactly how things looked back then.

Pretty much nothing. Why would i use it if there is an alternative?

Isn’t that a bit like someone faking a painting? Let’s say by Monet? This can be everything from 100% alright to illegal.

In addition to that, there’s also a difference between being inspired by, or copying something.

I think all of that is just a variation of an old and well known problem.

Or someone who studies art, has a look at art by other famous painters and then becomes a painter themselves.

Yes. I also think that’s how it is. If you want to generate something meaningful, something that contributes something deep, it is quite a lot of effort. You need to do the prompt engineering, generate a few hundred images. Skim through them and find the most promising ones, then edit them. Maybe combine more than one or put it back into the AI to get the right amount of limbs and fingers. And the lighting, background etc right.

You can just do one-shot, generate anything and upload it to the internet. But it wouldn’t be of the same value. But it works like this for anything. I can take a photo of something. Somebody else can have their photos printed on a magazine or do an exhibition. It’s a difference in skills and effort. Taking artistic photographs probably also takes some time and effort. You can ask the same question with that. Are photographs art? It depends. For other meanings of ‘OC’: Sure. The generated output is unique and you created it.