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Not sure if this is the place to ask but I am trying to set up a device on an Amazon Smart Plug so I can have it on a timer. I'm in the US using a 120V circuit. Plug is 120VAC, 60Hz 15A input, 15A max output Device uses 130W Am I right to assume the smart plug will work with anything that would normally work on the regular wall outlet since it takes in the same amps as it outputs?
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May 31, 2022 15:24
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Machai posted:Not sure if this is the place to ask but I am trying to set up a device on an Amazon Smart Plug so I can have it on a timer. Yeah that should be totally fine. The only time I'd be worried about a smart plug not being able to handle something is if you connected it to a really heavy load that would draw a ton of current when it first starts up, like a space heater or a big electric motor (like table-saw sized, not just a fan or something like that). e: To elaborate a bit, if it's rated for 15A it's gonna handle 15A, but unlike the wiring in the wall it's probably not rated for brief surges which is why you don't want to connect anything that's gonna exceed that 15A for brief periods. When a heater or big motor starts up it can spike to 3-4 times the current it normally takes, which your home wiring is totally fine with but the smart plug would definitely not be okay with. However the vast majority of things in your house aren't going to behave that way so for most stuff it should be totally fine, for example that 130W is barely over 1A so even if it did spike to a high current when it started up it'd still be well within the plug's ability to handle it. Shame Boy fucked around with this message at 15:38 on May 31, 2022 |
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May 31, 2022 15:31
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Shame Boy posted:Yeah that should be totally fine. The only time I'd be worried about a smart plug not being able to handle something is if you connected it to a really heavy load that would draw a ton of current when it first starts up, like a space heater or a big electric motor (like table-saw sized, not just a fan or something like that). It's a light. Also I may be an idiot when I said 120V circuit. This is the circuit breaker it is on.
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May 31, 2022 15:37
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Machai posted:It's a light. Nah that just says 120/240 because it's rated for either, if you're in the US and it's a normal wall outlet, it's 120V. The smart plug should be totally fine running a light, even a 130W one. e: To be clear by "normal" I pretty much mean "any outlet except those weird-rear end huge ones electric dryers use"
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May 31, 2022 15:40
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Shame Boy posted:I tried to interpret the picture without reading your post first and was like "is that some weird street sweeper" Thanks, nichrome that's the stuff! Forgot it existed but I see it every time I use the toaster.
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May 31, 2022 17:16
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I think you guys will get a kick out of this. At my local maker space, they get odd donations sometimes. But this one is the best I've heard of. An older lady brought this item in to donate, and supposedly the story is this: A relative of hers (Husband, brother, something) built it as a perpetual motion machine, or some kind of 'Tesla Generator'. Apparently the device killed or seriously injured someone when it was spun up, maybe it's maker. So it got donated.  Well, we started cracking it open today to see if there was anything useful inside that we could make use of. We knew the large discs had magnets inside, as steel would stick to the underside. We didn't even know what they were made out of, so I started cutting the duct tape off. There was probably 10+ layers of strong-rear end duct tape on the outside, and underneath I got a look at how it was constructed. The rotors seem to be made of wood table tops about 3 feet diameter sandwiched together with glue. We cracked them apart and found there were 6 pockets of magnets in each. They weren't even nice neodynium magnets, just plain ones in routed out pockets potted in with wood glue.  The main unit on the bottom was the most interesting. We could see a shitload of wires, so at least we figured we'd have some wires for the electronics folks or to scrap. But boy howdy once we peeled the coverings off was it interesting.  The coils look like large maybe microwave oven transformers. There's a smaller coil below each, and they're mummified in packing tape. All the wiring just looks like a mishmosh of lamp cord bundled together with more packing tape. The wooden structure itself is all hand made, the outside rim composed of individual wood wedges fitted together. Someone spent a fuckload of time and energy on this, and it's fascinating in a crazy way to try and work out what they were trying to do. I'm guessing it was a variation on the generator-hooked-to-a-motor perpetual motion machine. Probably they were thinking one set of coils would be energized by the magnets and drive the other half to push the rotor? Of course the other explanation is they just built a permanent magnet motor or generator, which honestly to me is even more bonkers.
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Jun 3, 2022 02:34
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I could definitely see how that would kill someone.
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Jun 3, 2022 02:45
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That looks like a vintage late 70s turboencabulator
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Jun 3, 2022 03:06
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Foxfire_ posted:That looks like a vintage late 70s turboencabulator There's no reticulated grammeter. That's a standard encabulator.
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Jun 3, 2022 04:13
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It's impressive all the same. Have you ever tried making wooden spurving bearings? Not for the faint of heart.
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Jun 3, 2022 08:36
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In my workshop I use a raspberry pi as my shop computer, mostly because it's what I had kicking around that can actually load up plans for projects/play a video or two. I also want to use it to do program arduino stuff. how out of date is the arduino ide you can get with through apt-get? Most of the stuff I was reading said it was really old, but that comes from pages written 2+ years ago. am I shooting myself in the foot doing that vs. just hauling my laptop in to the shop? e: I should add that I don't have wifi in the shop, so any internet access would be through tethering my phone
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Jun 3, 2022 20:46
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A Real Happy Camper posted:In my workshop I use a raspberry pi as my shop computer, mostly because it's what I had kicking around that can actually load up plans for projects/play a video or two. I also want to use it to do program arduino stuff. No idea, but I'm pretty sure you can just get up to date .deb's from the arduino site 
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Jun 3, 2022 20:56
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A Real Happy Camper posted:In my workshop I use a raspberry pi as my shop computer, mostly because it's what I had kicking around that can actually load up plans for projects/play a video or two. I also want to use it to do program arduino stuff. Just download the appropriate ARM tarball (32-bit or 64-bit) from https://www.arduino.cc/en/software and unpack it, I don't think you even need to run the install script just run the arduino binary in the folder it unpacks.
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Jun 3, 2022 20:58
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Anyone know how to get specs in amp hours for lead acid 12V car batteries? In particular a U1-3 form factor lead acid battery? I got an old generator with a super dead 12V starter battery and am trying to charge it. It started sipping current after a few minutes on my bench top power supply before rising to the 4A current limit I set at 14.5V with voltage falling to ~13.8V after ~2-3 hours and still current limited at 4aH. What I am trying to figure out is simply, how long should I leave it on the power supply for? I was able to get it to start the generator unassisted so it seems to have rejuvenated it at least enough to function once. A replace is only $40 but I'll likely only every use it if the power goes out due to major hurricane. EDIT: P.S. In case this helps someone this hurricane season: If your starter spins but doesnt engage, check your connection you might have enough current to freewheel the motor but not enough for the solenoid to engage the flywheel. In my case I had a bad ground. CarForumPoster fucked around with this message at 00:49 on Jun 6, 2022 |
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Jun 6, 2022 00:38
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For car/motorcycle batteries, there's an advertised value called "reserve capacity" specified in minutes and it's the amout of time a fully charged battery can provide 25 amps. Should be on the manufacturer's website next to cold cranking current. So you can just multiply that by 25/60 to get the total capacity in Ah.
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Jun 6, 2022 03:15
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Stack Machine posted:For car/motorcycle batteries, there's an advertised value called "reserve capacity" specified in minutes and it's the amout of time a fully charged battery can provide 25 amps. Should be on the manufacturer's website next to cold cranking current. So you can just multiply that by 25/60 to get the total capacity in Ah. Perfect, in this case it works out to 15aH which jives with what I’d expect. So figuring 4-5 hours at 3-4amp input charge is about right to charge it from dead without much risk (cells were full of solution)
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Jun 6, 2022 12:21
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I want to make a DIY PIC programmer. As part of that journey I have started analyzing this one: https://github.com/oh7bf/PiPIC/tree/master/RaspiPICprog It's for low voltage programming. I understand that applies to few PICs but my kirchoff math is rusty so I started here, I'll eventually work my way to something that can be used with as many different PICs as possible (HVP, ICSP, etc.). If you look at the electrical schematic you will see that GPIO7 is what sends signals to the Data pin. However, GPIO8 is ALSO connected to Vdata. Why? What's the purpose? Specially considering that if GPIO7 is low and GPIO8 is high, then more current will be pulled from GPIO8 than it can provide. And perhaps more important: where can I start to understand the whys of a PIC programmer? I understand that the point of the circuit I showed you is to provide a stable 5V to the clock, Data and other pins, sure, but where can I get a good schooling? I have the memory programming manuals of the PICs I want to use, and I can read the source code of the different FOSS programmers out there. Any good sources you'd reccommend, besides? Es mi dia primero! TIA
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Jun 6, 2022 13:15
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Dawncloack posted:I want to make a DIY PIC programmer. As part of that journey I have started analyzing this one: Just having a quick look, I'm pretty sure GPIO8 is meant to be the data input (so it should never be sourcing current) and GPIO7 is the output. GPIO7 can only source 5V into the data pin through 10k and GPIO8 is on a divider with a ratio of about 3/5 to generate a 3V logic level for the GPIO pin on the Raspberry Pi from the 5V data output of the PIC. Dawncloack posted:And perhaps more important: where can I start to understand the whys of a PIC programmer? I understand that the point of the circuit I showed you is to provide a stable 5V to the clock, Data and other pins, sure, but where can I get a good schooling? This is a tougher question since the answer is more about practice and experience than any one resource. Like if I were to tell you how I guessed that was an input without reading through source code, it's just because I've seen and designed things like this dozens of times before. You start to recognize patterns, eventually, sometimes. And I guess that's it, read schematics and datasheets, ask questions, try to work out alternatives, repeat. Having a textbook on hand is good for reminders on how to do the math. The Art of Electronics is a good resource and the first 2 chapters are enough to be able to start designing circuits like this one, but a huge part of it is having the experience to know when looking at any given circuit which bits of math are important and which are irrelevant, like in this case, I just checked the divider ratio on R10 and R8 and didn't get off in the weeds double-checking that Q4 was really in saturation. E: Removed possible reference to 
Stack Machine fucked around with this message at 04:54 on Jun 8, 2022 |
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Jun 6, 2022 14:31
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Stack Machine posted:The Art of Electronics is available for free Really, this is free? Do you mean as in because I didn't see anything about a free copy in their website: https://artofelectronics.net/
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Jun 7, 2022 04:56
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Maybe you meant Designing Electronics That Work? It's available as a PDF for free. https://designingelectronics.com/
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Jun 7, 2022 05:10
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qsvui posted:Really, this is free? Do you mean as in The third edition (the same one currently available in print) has been available for download on archive.org since 2020. I haven't personally confirmed it's there with the blessing of the publisher, but it strains credulity that such a well-known book would be left up for so long on a platform like that (with a US-based organization to sue and everything) without at least some implicit endorsement. (Edited for clarity because apparently I shouldn't post before 8 AM) Stack Machine fucked around with this message at 13:51 on Jun 7, 2022 |
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Jun 7, 2022 10:49
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That sounds like a huge stretch. I don't think there's anything wrong with saying "just google for a free copy" but flat out claiming that it's free is kinda misleading.
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Jun 8, 2022 04:06
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qsvui posted:That sounds like a huge stretch. I don't think there's anything wrong with saying "just google for a free copy" but flat out claiming that it's free is kinda misleading. Yeah, OK. Point taken and OP edited. I don't want anybody to accidentally do a copyright infringement without meaning to and the more I think about it the less sure I am that it's legit.
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Jun 8, 2022 05:06
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Does anyone know of a company or service for getting an old PCB reproduced from the original board and/or schematics? I've got a board that controls one axis of a huge milling machine that has failed. I have the bad part, a good copy of the same part that still works, and the original drawings for the thing. Basically I'm trying to find some place that can turn those into gerber files or similar so I can get a few spares made. Here is what the board and drawing looks like. This is all stuff from the 70's at the latest.  Here is the big mill the board goes in just because it's huge: 
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Jun 8, 2022 14:42
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bullets cure cops posted:Does anyone know of a company or service for getting an old PCB reproduced from the original board and/or schematics? I've got a board that controls one axis of a huge milling machine that has failed. I have the bad part, a good copy of the same part that still works, and the original drawings for the thing. Basically I'm trying to find some place that can turn those into gerber files or similar so I can get a few spares made. Here is what the board and drawing looks like. This is all stuff from the 70's at the latest. Goddamn, I never thought a post could capture my interests so succinctly. Looking forward to responses from people more knowledgeable than I. I’m the guy in the back, pissed that he had to leave his stool for you to take your picture
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Jun 8, 2022 15:47
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bullets cure cops posted:Does anyone know of a company or service for getting an old PCB reproduced from the original board and/or schematics? I've got a board that controls one axis of a huge milling machine that has failed. I have the bad part, a good copy of the same part that still works, and the original drawings for the thing. Basically I'm trying to find some place that can turn those into gerber files or similar so I can get a few spares made. Here is what the board and drawing looks like. This is all stuff from the 70's at the latest. Honestly I'd think you'd probably want to look for an actual certified EE contractor to do that. If the thing fails catastrophically and your insurance company wants to know why the hundreds of thousands of dollars of machine shop equipment is on fire telling them "well we used some rando service to replace a circuit board" might not work out too great. It doesn't actually look all that complex though, I bet a lot of people in this thread could do it (and I'd fuckin' love to take a whack at it) but I'm just some dude on the internet lol
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Jun 8, 2022 16:18
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Shame Boy posted:Honestly I'd think you'd probably want to look for an actual certified EE contractor to do that. If the thing fails catastrophically and your insurance company wants to know why the hundreds of thousands of dollars of machine shop equipment is on fire telling them "well we used some rando service to replace a circuit board" might not work out too great. I've reached out to a couple of EE contractors to see if they would do something like this, maybe one of them will. If we can't find someone that will reverse engineer the board, we will probably end up paying someone to rip out the ancient control system and upgrade it to something more modern. I was just hoping getting the board replaced would be quicker so we could get it back in action, but I see your point about the insurance issues this could raise. Here are some more pics of the machine since I have them here anyway: https://imgur.com/a/x2CBpuY
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Jun 8, 2022 16:40
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That's a big boi DirtyPCBs has a destructive PCB reverse engineering service. It's cool, but it might not be the best approach here. Honestly, I'd go in the other way from hiring an engineer. I'd figure out the inputs and outputs on that board and just buy a modern equivalent. I'm sure there is one. I also haven't looked at the schematic while phone posting
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Jun 8, 2022 16:47
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I'm not an expert, but I agree that the inputs and outputs of the machine are likely less complicated than the board controlling it, and it might be easier to just get a modern controller to interface with the machine.
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Jun 8, 2022 17:11
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I agree with everyone that I need to get an engineer involved. I just wasn't sure what kind of company to approach for this sort of thing. The whole machine's control system will definitely get modernized in the near future, I was just trying to do this in the mean time, since the board is purely discrete components I thought some company might be able to create some gerber files based on it pretty quickly. This mill has the largest work holding capacity out of all our equipment, (well technically we have at least one lathe than goes bigger, and another mill that is bigger in at least one direction) so having it out of action puts a lot of jobs on hold. edit: namlosh posted:I’m the guy in the back, pissed that he had to leave his stool for you to take your picture lol! he isn't pissed, he's excited because he has spotted someone to kill time bullshitting with instead of sitting on that stool for hours at a time. bullets cure cops fucked around with this message at 17:46 on Jun 8, 2022 |
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Jun 8, 2022 17:43
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I just realized that the stool is sitting on what is also a work surface for the mill.
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Jun 8, 2022 17:55
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I mean, that's explicitly what I said you didn't need to do!
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Jun 8, 2022 18:07
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ante posted:I mean, that's explicitly what I said you didn't need to do! Oops, yeah sorry I forgot to reply to that. With the documentation being entirely in Czech (I think?) and this type of thing being well outside the scope of the kind of minor electronics work I've done myself, I'm nowhere near confident enough to try and reverse engineer the ins and outs of this thing. It's all analog, the only pins labeled are what I assume are the voltage rails (+24, +15 and -15).
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Jun 8, 2022 18:20
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I believe in my heart that if you hooked that thing up to an AI, it would murder us all and turn our bodies into stools
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Jun 8, 2022 18:37
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namlosh posted:I believe in my heart that if you hooked that thing up to an AI, it would murder us all and turn our bodies into stools Justified imo
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Jun 8, 2022 22:53
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Good news, there are data sheets out there for those 40+ year old transistors. Whoever does the revers engineering won't have to go in completely blind. https://datasheetspdf.com/pdf/551372/TeslaElektronicke/KU611/1
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Jun 9, 2022 02:00
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Yeah I wouldn't DIY a fix for that beast. Hiring someone qualified to do a modern electronics refit of it seems like the less exciting and more expensive but safer option.
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Jun 9, 2022 02:09
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So, does anybody ever have to get out a little screwdriver and carefully adjust R32 (the 4k pot in the lower right of the photo? Like, what does that big ol' thing do if that's out-of-adjustment or dirty?
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Jun 9, 2022 03:55
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Stack Machine posted:So, does anybody ever have to get out a little screwdriver and carefully adjust R32 (the 4k pot in the lower right of the photo? Like, what does that big ol' thing do if that's out-of-adjustment or dirty? Noone that still works there can remember anyone ever adjusting the pots. I wondered if it might be a really rough way of tuning the motion of the machine on that axis, changing how fast it ramps up/down it's speed, but I have no idea. I emailed a couple of places that modernize the controls in old mills like this today. Hopefully one of them will just come and completely replace the ancient electronics in it. It will take a while but I'm out of other ideas. Thanks for the recommendations everyone. CopperHound posted:Good news, there are data sheets out there for those 40+ year old transistors. Whoever does the revers engineering won't have to go in completely blind. I saw that! It doesn't do me much good though. So many of the components on the board are made by Tesla (not that one lol). I had never seen anything of theirs before this.
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Jun 9, 2022 04:14
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Honestly, it seems like a really basic driver to recreate, for the most part. I'm a little confused by C19 / R53 unless the thing is AC or only able to do very short pulses. To be clear, I'm not suggesting that you recreate it. Just that it would be fun.
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Jun 9, 2022 04:27
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