electronics

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asbestos, in Bought my first "bench" power supply 😁
@asbestos@lemmy.world avatar

Thank you so much for this post! I’ve been wanting a bench supply for years but never liked the fact they’re huge so I stuck with the same method as you.
Please give an update after a while, I’m really interested hows it goes!

Eufalconimorph,

The small supplies are nice for size, but tend to have more noise than the big linear supplies. If you’re working with low-precision DC circuits, or even stuff up to audio frequencies (basically still DC) it’s not likely to be an issue. If you’re working with RF circuits it’s more likely to be an issue, though of course if they’re not too close to the switching frequency it’s easy enough to filter the output.

asbestos,
@asbestos@lemmy.world avatar

Thanks for the info! Do you have any suggestions for low-noise supply that isn’t huge and doesn’t break the bank?

Eufalconimorph,

The “isn’t huge” is the issue. Linear supplies need a rather big transformer to work with 60Hz mains instead of chopping it up at 20kHz or more like switchers do. I’ve got a Siglent SPD 3033X-E (decent, reasonably cheap) and a BK Precision 9201 (better, more expensive).

Tolookah, in Buying replacement Type C connectors

All the dimensions matter, if you don’t get the posts right, it won’t hold to the board well and you’ll be back here, possibly with worse problems.

If the pins aren’t right, you just won’t have anything. See if you can find a part number or manufacturer marking anywhere on the connector, as it would narrow your search down plenty.

jaspersgroove, (edited ) in Buying replacement Type C connectors

This is the biggest flaw with usb c, though I seem to get downvoted and ridiculed whenever I point it out. The retaining pins are part of the port itself, not the cable plug as is the case with micro usb and lightning cables. So when the retaining system breaks, you can’t just go buy a new cable, you have to replace the port.

The pinouts are standardized so you should just be able to count the number of solder joints and find a connector that mounts to the pcb the same way as the one you’re replacing. Just eyeballing it I found one that looks pretty closed linked below, but I would advise you to do some more research on your own and not just take my word for it.

www.digikey.com/en/products/detail/
/13913753

Looks like this is a fairly common issue for your device, unfortunately. reddit.com/
/xppen_deco_pro_small_ccable_port/?rd


TrickDacy,
@TrickDacy@lemmy.world avatar

though I seem to get downvoted and ridiculed whenever I point it out

Apparently not. I love how when people say this they usually have more upvotes than downvotes

jaspersgroove,

There’s a first time for everything. Maybe it’s because my previous conversations on this topic happened on Reddit and anyone that doesn’t join the USB C circlejerk there is immediately treated like a moron.

TrickDacy,
@TrickDacy@lemmy.world avatar

I’m guessing it sounded like you were shilling for apple.

I will say that the “circlejerk” circlejerk is tired.

Standards are good. Proprietary apple garbage is not

jaspersgroove, (edited )

Could be, guess it’s my fault for thinking that a charging system should first and foremost be a robust connector and cable system capable of charging a phone, not a fragile “do it all” cable. The biggest drawback with any “do it all” system is that the “all” that is done is inevitably done poorly. You want to defend a connector system that requires going to a repair shop and waiting for hours or days instead of a 10 minute trip to the nearest gas station or convenience store to remedy, be my guest.

TrickDacy,
@TrickDacy@lemmy.world avatar

Haven’t had to have a repair shop deal with any of the 30+ usb-c devices I’ve had.

The funny thing here is you’re trying to say that lightning cables are just meant for charging and they weren’t. They were meant to make money by creating a proprietary licensable technology that mimics usb-c in almost every way

jaspersgroove,

We are literally having this discussion in a post where the usb c port is broken so your choice of sharing your anecdotal experience is deliciously ironic.

I don’t care what it was designed to do, I care about what it does. And what it does is hold up better than usb c, not require a trip to a repair shop if the connection fails, and do a perfectly good job of charging a phone or any other device that it supplies sufficient current to charge.

glibg10b,

I know this is just an anecdote, but I’d like to add that this is the second time this has happened to me with this model of device, and both times were after minimal usage

TrickDacy,
@TrickDacy@lemmy.world avatar

TIL if you post a picture of your anecdote, it becomes universally objective truth. If you describe it in a comment, it’s useless and “delicious irony”

Apple is trash, shill all you want.

southsamurai,
@southsamurai@sh.itjust.works avatar

I’m not disagreeing with you, I’m looking for better understanding of your opinion.

My understanding of the retention being part of the port is to make it less likely for the port to be damaged by use, requiring more difficult replacements compared to the added stress from on cable retention on older formats.

So far, that’s matched my personal experience, where my usb-c devices’ ports hold up better than my micro usb ports. The handful of micro usb devices I have left all have loose ports currently, and did after as little as a year of use. None of my usb-c do, with of of those approaching three years of use (iirc, might be a little less).

Isn’t that a good thing for long term device life?

jaspersgroove,

It all depends on the user and the use case, really. My usb port on my Nintendo switch failed within 2 years and I had to get it replaced, but I have other devices where the usb c seems to work fine. I think the one on the switch broke because I tended to rest it on my stomach while I was playing undocked. On the other hand I have an iPhone 11 that I still charge using the lightning cable that came with my iPhone 6, cuz it just sits there on my bedside table and never really sees any mechanical stress.

USB C is great don’t get me wrong, but to me creating a situation where it is harder for the end user to deal with a failure does not seem like a good thing. Not everyone has the training or the tools to disassemble complex electronics and perform delicate soldering jobs, to say nothing of the e additional time required to make that kind of repair compared to just running to the nearest convenience store and grabbing a new cable or, more likely, just grabbing another one of the 6 you already have in your junk drawer.

southsamurai,
@southsamurai@sh.itjust.works avatar

Fair enough! Thanks for the time :)

I can see that being an issue for sure, what with repairability already being such a dismal thing in electronics. I kinda forget that not everyone is comfortable with opening things up as well. Just that barrier to entry is enough for plenty of people to just buy the next thing instead of repairing.

dgriffith,

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.

nilloc,

People keep mentioning that lightings sockets are built to wear out, but I have iPhone 5S and 5C (the really old color) phones that are still working perfectly. Cleaning lint out occasionally is the only irritant I’ve had with these connectors.

I know it’s anecdotal, but between my family and our years of devices, and that my MacBook Pro with USB-C charging is the most finicky of all my devices, I’m a disappointed by the switch from Lightning connectors. Time will tell though I suppose.

JustEnoughDucks, in My customisable solar hot water system controller (project in progress)
@JustEnoughDucks@feddit.nl avatar

Just as a PCB designer, make sure that you spec out the 240V voltage neutral and live copper trace width to the current going through them. For example, at 10 amps, those traces look much too small. Is it going to be in a high humidity environment? The spacing between traces also should be bigger for creepage/clearance reasons.

Cool project though!

dgriffith,

Yes the traces are pretty light for those kinds of currents, and I did have some concerns on the track spacing around the SCR and the screw terminals. The fatter tracks use a spacing for 240v that I looked up online.

Humidity here isn’t “tropical” as such, the board will probably get a coat of lacquer anyway.

The circulating pump is rated at 240v/20 watts (so not much current when it’s running steady state), and the SCR I’m using is good for a few amps of continuous current draw with a fairly high surge current. The SCR has minimal heatsinking so it will go first in extended high current situations, there’s going to be a panel mount fuse before all of this that I’ll probably set to 2 amps or so.

The zero-crossing SCR controller I’m using “should” prevent switching on the pump at the peaks of the mains cycle so max current should just be the initial stall current from the motor before it gets up to speed.

The pump is an induction motor so the only concern I’ve got is false triggering of the SCR and being unable to turn the pump off once triggered. I used an example snubber circuit from the data sheet of the zero crossing controller and of course they said “your milage may vary”.

roterabe, in My customisable solar hot water system controller (project in progress)

OK this is interesting, but also differs. If I have read correctly, you’re circulating the water in the system as a whole.

I’m also using a solar setup, but I’m using a serpentine coil running a separate coolant liquid. The coolant is used since winter goes from -10 to minimim -20 degrees celsius.

What are your coldest months like?

dgriffith, (edited )

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.

roterabe,

Hmm, the heater element being controller disregarding your will is a bit of a bummer.

Thanks for clarifying, so you are indeed circulating the water itself, it’s not a separate line used as a heater. In this case you really are at the mercy of either your pump, pipe length, ambient temperature, insulation and/or sun intensity.

Have you monitored the temperature at the panel on the roof itself? Also, what type of insulation are you running on those pipes?

dgriffith,

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.

roterabe,

Yeah, that seems like a good way to go. 65 degrees at ground level is what I’d also expect. My assumption up top would be close to 90/95 degrees. Driving the pump more often would be interesting.

linker3000, in Community seems dead. Can we mirror reddit posts here?

Interesting comments all round. Let’s run with the discussion for a week to allow infrequent visitors a chance to comment and then see if there’s a strong trend towards a specific opinion.

Eufalconimorph, in Community seems dead. Can we mirror reddit posts here?

If there’s more activity on Reddit then here, then Reddit repost bots make it feel like all the community action is happening on Reddit. They push people back to Reddit because that’s where all the new posts are coming from, so why engage here if the active discussion is already in progress over there?

jonno,

Communities with >50% repost content are unsubscribed by me. If I have communities spamming my timeline with reposts, I just block em. Having to open at least two link and read the content on both sites just to get the info and understand the discussion/context is generally a huge waste of my time.

rglullis,
@rglullis@communick.news avatar

I am giving you real data: the communities where the mirrors are active end up with more organic activity than those without.

Eufalconimorph,

Interesting. I’ve mostly seen communities overwhelmed with bot posts and 0 replies, but I haven’t taken any statistics.

DogMuffins,

Bit they’re giving you real data.

Eufalconimorph,

No, they made an assertion, without statistics or raw data to back it up. How many replies do cross-posts get, compared to regular posts? What’s the mean? What’s the median? Does the distribution look Gaussian, and if so what’s the standard deviation.

DogMuffins,

I was being sarcastic. I always forget the /s.

xoggy, in Community seems dead. Can we mirror reddit posts here?

Rather than mirror reddit posts here, you can set up a dedicated community for that so people that want that kind of thing can get it. No need to kill an existing community further.

rglullis,
@rglullis@communick.news avatar

That’s exactly what I am doing for lots of communities that have no reddit equivalent, and what I did for !main when it was clear that !selfhosted was already somewhat active. Regarding these, go take a look at the usage numbers for both, tell me which is going up and which is going down


breadsmasher, in Community seems dead. Can we mirror reddit posts here?
@breadsmasher@lemmy.world avatar

Mirroring reddit posts is so incredibly annoying

rglullis,
@rglullis@communick.news avatar

The point is not just to mirror posts, it’s also to create a clear migration path for people who are still using reddit because the niche communities have not achieved critical mass here.

Besides, those who are on lemmy.world have nothing to worry about because the LW admins have defederated from alien.top.

DogMuffins,

Cross-post bots are not the way to build a community.

Imagine signing up and finding that all the posts are just cross-posts from reddit with barely any engagement.

One of the main things I despise about this concept is that it provides an implication that lemmy is some kind of budget-reddit. As though, all the good content is on reddit but we’re all camped out here on lemmy.

The way to build a community is to simply post more.

To respond to your other comment here also:

I’m working on two-way communication. Responses to a mirrored comment here will trigger a notification to the original reddit poster and a comment to the reddit thread linking to the lemmy conversation.

Would this even be allowed on reddit? Surely from the perspective of a reddit mod / admin this would just be spam?

the initial posts are enough to foster a discussion between people on Lemmy

That’s not my experience. I’ve only ever seen dozens of cross posts with no comments.

rglullis,
@rglullis@communick.news avatar

Cross-post bots are not the way to build a community.

The community already exists, it’s just that they are located in a place where we don’t want to be. The goal is to get the majority to switch and re-center in a place that is determined by the intolerant minority.

As though, all the good content is on reddit but we’re all camped out here on lemmy.

Which is true, if we are being honest. And if we are being even more honest with ourselves, most of the people that came to Lemmy are going back to Reddit because there is no content for the niche communities here. I mean, look at this community: last post is from 27 days ago. Do you really think that it is doing well by itself?

We had over 100k MAU in July. We are down to 35k and it keeps going down.

Our problem should not be with the people on reddit, but reddit itself. Instead of pretending that we don’t care about the people there, we should try to find ways to bring them here.

Would this even be allowed on reddit? Surely from the perspective of a reddit mod / admin this would just be spam?

The comment would not be coming from a bot account, it would come from the redditor who have used the “Fediverser portal” to connect the accounts (and given permission to send comments) so it would also be “organic”.

DogMuffins,

The community already exists, it’s just that they are located in a place where we don’t want to be.

Both of us are just going to have to acknowledge that our thoughts around online communities are very different.

Back in June I was thinking along the same lines as your good self, as in “what can we do to move /r/whatever to whateverinstance.tld/c/whatever”. I eventually realised that not only is that not possible, it’s antithetical to the idea of online communities.

An online community is not a set of users, it’s a combination of culture and momentum. Sure there might be a few key core personalities that everyone recognises from day to day, but if those users left the community would continue because it has an established culture and momentum - a collective recollection that this is the place to go for a certain flavor of content and engagement with that content.

The thing is, you can’t force it. You can’t create a culture because it’s a combined input from many people. All you can do is create the environment within which the right type of culture will coalesce. You can’t herd the swarm of bees that is /r/electronics to /c/electronics. All you can do is make /c/electronics the most favorable place to build a hive and have confidence that /r/electronics is becoming less favorable over time.

I mean, look at this community: last post is from 27 days ago. Do you really think that it is doing well by itself?

The solution I’m proposing is to post real actual content. Subscribe to some rss feeds, look at old magazines, ponder questions for discussion. Any single post like this has 100 times the value of something re-posted from reddit.

We had over 100k MAU in July. We are down to 35k and it keeps going down.

That’s one metric. It doesn’t feel like content and engagement has really reduced much in the last several months. Honestly I suspect that the orchestrators of the influx of bots in July have realised that other platforms are more fertile for scams and manipulation et cetera.

Besides which, even if valued users are leaving, that’s kind of disappointing but a re-post bot isn’t going to change that. The kinds of community builders you’re looking for are critical thinkers like your good self putting effort into building good communities.

The comment would not be coming from a bot account

Foregive me, I’m not familiar with alien.top - I’ll have to take a look.

Technically, such a bridge is going to be interesting I guess and I have to concede that in some cases it might facilitate discussion.

That said, it’s still based on the (IMO flawed) premise that mirroring content from reddit is the right move. From my impractical purist / idealist perspective. Lemmy should not seek to be new-reddit. Just let lemmy be lemmy - allow it’s culture and communities to emerge and coalesce in their own time.

rglullis,
@rglullis@communick.news avatar

An online community is not a set of users, it’s a combination of culture and momentum.

Agree, 100%.

The thing is, you can’t force it.

Agree, 100%.

The solution I’m proposing is to post real actual content. Subscribe to some rss feeds. Any single post like this has 100 times the value of something re-posted from reddit.

That’s where we disagree. Not because I don’t think there is value in what you are saying. There absolute is value and it is very important that we have real people doing. But I don’t think this is enough.

The problem is that we can not do that for all of the interests that we have. Do you know the rule of “1/9/90” of social media? I had about 40 subreddits I was subscribed to, and I would post to 1 or 2 (rarely), comment on about 5 (more frequently) and just lurk around the rest. /r/electronics is in the latter category.

I mean, go look at my profile history. I think I posted more than 300 posts with content from many different communities. My past time this summer was to find different content to post in the different communities I was subscribed to or even that I created myself. I would sometimes even go out of my way to make a post about something where I knew I wouldn’t get the answer, but I thought it would be better to write it down as a way to show some signs of life. And you still think that I should “go read some books so I can ask questions”?

No, I’m sorry. That is just too much. It is a lot easier (and effective) to just write a tool that can bring the content in the format that I want, and hope that it can be useful for others.

The thing is, this tool is definitely built for the 90%, and the reason that it is working it precisely because of that. I am closer to leave reddit altogether because this tool lets me read things here. The more people are able to do this, the more the network effects will kick in and the easier it will be for the communities to move. It won’t be “forced”, but we will get to the point where the majority will be able to say “it’s fine either way by me, so I might as well do it from lemmy”.

Tolookah, in Community seems dead. Can we mirror reddit posts here?

I think mirroring questions and requests for help is a terrible idea, no one is going to want to answer a question here if most of them are mirrored and the original asker is not here to get the answer.

It’s frustrating to put out a well thought out answer then realize that the person who asked will never see it.

rglullis,
@rglullis@communick.news avatar

Your points are valid, but turns out that the practice is showing different results:

the original asker is not here to get the answer.

I’m working on two-way communication. Responses to a mirrored comment here will trigger a notification to the original reddit poster and a comment to the reddit thread linking to the lemmy conversation.

It’s frustrating to put out a well thought out answer then realize that the person who asked will never see it.

This is not what is happening at the selfhosted communities. Turns out that a lot of the initial posts are enough to foster a discussion between people on Lemmy already.

Tolookah,

Personally, I’ve blocked most repost bots (as I see them), because of the above stated reasons. I know I’m just one data point in a statistic, but I’m one that comments, as opposed to one that just lurks.

rglullis,
@rglullis@communick.news avatar

My main goals with this tool are:

  • completely drop reddit without losing access to its content and the communities that are there.
  • create a migration path for the people who are on reddit and don’t want to give it away because there is no real alternative.

I’m also one that comments, I just don’t want to do that on reddit anymore. I want to be able to do that on Lemmy, and have the two-way bridge until the community here is self-sustainable. This is how I think this tool can be helpful.

nilloc, in A 74xx-defined Radio

Rad project with parts that us hoarders might already have in our junk bins.

comfortable_doug, in Advancing Cu-Cu Hybrid Bonding: Overcoming Challenges for the Future of Semiconductor Packaging | Microwave Journal
@comfortable_doug@hexbear.net avatar

Probably also makes for faster assembly times

al177, in Use Cases And Value Proposition Of eFPGA (Embedded FPGA)

This makes sense only if you’re rolling your own silicon, and it depends on the application. I could see this as an alternative to a scalar DSP core or to provide more flexible high speed interfaces. The unspoken cost is going to be adding another proprietary set of tooling in the BSP for your chip.

amyi, in How Resistors Work - Unravel the Mysteries of How Resistors Work! (The Engineering Mindset)
Rolive, (edited ) in What project are you currently working on?

An MPPT solar charge controller using Arduino as well as a homemade Li-Ion battery. Also an 18650 battery tester. So 3 projects simultaneously because they’re closely related.

I’m using a CC CV boost converter to convert solar energy to the voltage for a 7s Li-Ion battery. The arduino reads voltage and current and will try to adjust the CC value to obtain an optimal wattage. I have removed the CC potentiometer and replaced that with an Arduino PWM pin with voltage divider that sets the corresponding current limit. This way a relation between CC pwm duty cycle and solar output can be set.

DIY Li-Ion battery goes hand in hand with the solar project. I’m making a home battery out of salvaged laptop batteries. That requires a battery tester as well which I’m also making myself. The battery tester works by charging a battery with a TP4056 module and discharging as soon as it’s fully charged over a resistor while monitoring voltage/current over time. This happens 16x in parallel using multiplexers so 16 batteries can be tested simultaneously.

I’m also taking safety very seriously so all batteries are equipped with both thermal fuses and current fuses. That involves 3D modelling battery holders, printing them, spot welding/soldering etc. As well as an additional monitoring system on top of a commercial BMS so that the battery status can be monitored remotely. I intend to have a smoke detector, thermostats and an emergency cutoff switch controlled by that second BMS.

Once everything works to a somewhat satisfying degree I intend to post the projects in more detail.

Every project tends to explode in scope in terms of what it all requires so I’m not making as much progress as I want but it has been very educational.

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