Serious question from a beginner in electronics. For reasons I do not fully understand, I have become fixated on the idea of collecting small amounts of electricity from “interesting” sources. I don’t mean “free energy”, instead, I mean things like extracting a few mV from being so close to a AM radio tower using two...
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.
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.
It seems like there’s been a lot more websites that have been deploying anti-adware blocker software in the past few weeks. One that stands out in particular is called Admiral (see websites like GameRant for an example)....
I wanted to try a japanese dish called tamago kake gohan, it’s basically raw eggs mixed with rice. The problem is that I’m scared to get salmonella from it. Do you guys think it’s safe to eat them? I’m currently living in Brazil. Also, I saw this article telling that the brand I buy my eggs from is exporting to Japan,...
well, i was taught the salmonella is on the shell (mainly). so this would be no good advice. i don’t know anything about pasteurized eggs, though. nor north or south american eggs.
I have contributed to a ton of (free) information that was helpful and didn’t have the heart to delete all my posts that I spent days/months doing. Is there an easy way to bring all those over here?
Most of us in Lemmy know the importance of privacy and owning your devices in a big tech owned world (me included) but for once I thought to make the opposite question and ask if there are products by them that you actually use and enjoy them....
I was having a friendly discussion with someone this morning about PC and Laptops for work/education stuff, he suggested that I could use a chromebook for all this stuff and this would be a good idea and make things easier. I strongly disagreed with this, mainly because I hate laptops, the keyboard and touchpad make me angry and...
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.
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.
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.
First off: This post is about a tiny Leatherman multitool. Not a gun, not a sword, not something that can actually hurt someone. Just a small, harmless tool that is unfairly banned from planes because of onerous TSA regs. No one is going to do 9/11 with tiny pliers and a fingernail-sized screwdriver....
I don’t think you’re getting downvoted because of this. You’re not sharing a tip, but asking for advice.
I don’t have any real advice. I forgot my swiss army knife in my backpack a few times. Seems to be completely random if it gets detected. Maybe if the operator of that machine is paying attention. But these x-ray machines and metal detectors seem to work.
Edit: Sorry. Didn’t see this post was already kind of old.
Yeah. I’m mistaken. Sometimes I read things too fast. Thx. And good luck with your multitool. I feel you. I don’t leave the house without my trusty swiss knife, a spoon, some duct tape and cable ties. And I use these regularly in everyday life and even more so while travelling. I can eat yoghurt everywhere, MacGyver me out of situations and fix somone’s broken-down trolley at the airport with the cable-ties. With those things you’re not only prepared for every situation, but you occasionally make someone’s day.
Hi, this post is structured similarly to r/PrintedCircuitBoard 's review request format. Since we don’t have any PCB communities over here yet, I thought that this might fit in here and can maybe spark some friendly discussion....
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?)
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.
Maybe advertise your idea to the right people… But you’re right. Starting a new communitiy takes some effort and more than one person to get things rolling.
This makes no sense to me. There’s people in the comments literally telling me to go kill myself and that’s fine but, me politely disagreeing is worthy of a 30 day ban.
Judging by the comments here, I’d say it isn’t working. (That doesn’t mean it’s necessarily your fault at this point.)
All I want to say is: You and the people outright attacking you here are setting the tone of the conversation. I don’t feel entitled to lecture anyone on how to spend their time on the internet. For me, this thread is too toxic and not my vision of what Lemmy should be like.
Unfortunately, the really toxic people have arrived here, targeting you and spreading hate. I don’t think this going to become a productive conversation after that. And I really don’t have good advice here. I’m going to flag the comments that are hatred and then I’m out. I’m going to focus on some more productive things somewhere else. I wish you the best. Hope Lemmy strives to become a space for diverse opinions, constructive debate and not hatred and small-mindedness.
I see more and more toxic behaviour here. I get that this war/conflict gets to us. And everyone has strong opinions and the debate is emotional. But it reminds me more of the toxic atmosphere that used to be part of Twitter.
I suppose the mods of political communities are having a bad day since the conflict escalated. And they are part of the debate, sometimes maybe making their decisions emotional, instead of neutral and based on reason alone. I -personally- think a 30-day is a lot, even if it is spreading misinformation. But I didn’t have a look at the facts here.
Judging by your comments in general, you seem quite an argumentative person. I usually don’t like people focusing on negativity and (for example) debunking a single argument out of a post and then concluding they’re right and someone else is entirely wrong. It leads to us having unproductive and stressful conversations, once we manoeuvre ourselves to opposing sides that lose the ability to communicate productively and grasp the bigger picture and the context that things are set in.
So. Please whoever is in the right or wrong, make Lemmy a nice place and not a clone of the toxicity and argumentativeness on Twitter. And don’t yell at people too much.
OP, please be aware you’re often a very argumentative person and a big part of your way of talking to people is opposing them.
Disclaimer: this is not specifically for a commercial product, but various things I design sometimes get commercialized. I mention this so that you may decide whether you want to weigh in. If it’s commercialized, I will probably make very little money but a bunch of university students may get a neat STEM program in the...
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.
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.
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.
Blocking posts?
Is there a way to block posts from specific lemmy communities? I want to browse “All” without having to worry about porn showing up
Is “harvesting” small amounts of electricity a fools errand?
Serious question from a beginner in electronics. For reasons I do not fully understand, I have become fixated on the idea of collecting small amounts of electricity from “interesting” sources. I don’t mean “free energy”, instead, I mean things like extracting a few mV from being so close to a AM radio tower using two...
How Do You Combat Anti-Adware Blockers on Android?
It seems like there’s been a lot more websites that have been deploying anti-adware blocker software in the past few weeks. One that stands out in particular is called Admiral (see websites like GameRant for an example)....
How safe is it to eat raw eggs?
I wanted to try a japanese dish called tamago kake gohan, it’s basically raw eggs mixed with rice. The problem is that I’m scared to get salmonella from it. Do you guys think it’s safe to eat them? I’m currently living in Brazil. Also, I saw this article telling that the brand I buy my eggs from is exporting to Japan,...
deleted_by_author
Is there an easy way to bring all my old technical posts from Reddit to Lemmy?
I have contributed to a ton of (free) information that was helpful and didn’t have the heart to delete all my posts that I spent days/months doing. Is there an easy way to bring all those over here?
Why hasn’t r/circlejerk made there presence known on lemmy?
I liked going to there sub once in a while. Can someone with a Reddit account message the mods and see if they can get some content over here?
What movie did you rewatch most often?
For me, it’s either the Matrix or Pulp Fiction. I have seen both a lot of times but certainly not more often than say a dozen times.
What's a big tech product that you actually find useful?
Most of us in Lemmy know the importance of privacy and owning your devices in a big tech owned world (me included) but for once I thought to make the opposite question and ask if there are products by them that you actually use and enjoy them....
Do you prefer PC or laptop? (freeonlinesurveys.com)
I was having a friendly discussion with someone this morning about PC and Laptops for work/education stuff, he suggested that I could use a chromebook for all this stuff and this would be a good idea and make things easier. I strongly disagreed with this, mainly because I hate laptops, the keyboard and touchpad make me angry and...
Do AA Battery Holders - Connected in Parallel so still 1.5V - Exist?
Hello,...
[Request] How to get a tiny multitool past airport security?
First off: This post is about a tiny Leatherman multitool. Not a gun, not a sword, not something that can actually hurt someone. Just a small, harmless tool that is unfairly banned from planes because of onerous TSA regs. No one is going to do 9/11 with tiny pliers and a fingernail-sized screwdriver....
PCB Design Review Request: ESP32 Smart Relay Board
Hi, this post is structured similarly to r/PrintedCircuitBoard 's review request format. Since we don’t have any PCB communities over here yet, I thought that this might fit in here and can maybe spark some friendly discussion....
Is there an instance to request the creation of new instances?
For those of us that don’t want to become admins or mods....
Banned for not breaking the rules, but disagreeing with a mod (i.ibb.co)
This makes no sense to me. There’s people in the comments literally telling me to go kill myself and that’s fine but, me politely disagreeing is worthy of a 30 day ban.
Considering positioning strategies for autonomous mechanum-wheeled robots
Disclaimer: this is not specifically for a commercial product, but various things I design sometimes get commercialized. I mention this so that you may decide whether you want to weigh in. If it’s commercialized, I will probably make very little money but a bunch of university students may get a neat STEM program in the...