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Big same. Especially with my work stuff, it's hard to know whether any particular design will end up being a one-off that gets abandoned, or we'll go hard and press the button to get 1000. That bleeds over into my personal stuff where everything is technically manufacturable, even if it's not likely to happen. Turns out it's not that much extra work if it's something you do all the time anyway.
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Oct 16, 2022 22:28
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ante posted:That bleeds over into my personal stuff where everything is technically manufacturable, even if it's not likely to happen. Turns out it's not that much extra work if it's something you do all the time anyway. It's a whole lot of extra work when it's not something you do all the time. But, like Shame Boy said, it's fun; and when it comes to hobbies, my time is worthless.
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Oct 16, 2022 22:44
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There's only one foolproof method for detecting a bear:quote:Stephen Colbert: I would blow Dane Cook fucked around with this message at 02:10 on Oct 17, 2022 |
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Oct 17, 2022 00:21
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ante posted:Big same. Especially with my work stuff, it's hard to know whether any particular design will end up being a one-off that gets abandoned, or we'll go hard and press the button to get 1000. Yeah that's why I always do it, I can never tell when something is going to get reused later or be a one off, so it's best to assume reuse. Even in my personal stuff, making lots of design notes and tracking revisions makes it much easier to come back months or years later and work out what the hell is going on, whether I want to make another one or reuse parts of a design.
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Oct 17, 2022 01:37
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cruft posted:It's a whole lot of extra work when it's not something you do all the time. But, like Shame Boy said, it's fun; and when it comes to hobbies, my time is worthless. Man I'm really feeling this. Everything takes forever the first time around.  Also, I finally got that class D amp hooked up and playin' some tunes. https://imgur.com/NF4iLrY (guile's theme) https://imgur.com/He91Owj (that one reddit song)
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Oct 17, 2022 04:02
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So I think I have come up with a good first project for myself. I have this mid-90s era Halloween decoration, which consists of a skull in a frame, and there are light sensors on either side. When you walk by the frame, depending on the side, the skull will look towards you and greet you. I bought it NIB from eBay, and since batteries are usually installed on things like that (Try Me button), of course the 30 year old batteries were corroded as poo poo. Had to replace the entire battery clip, which unfortunately was molded into the entire frame itself. So I cut it out with a dremel, and managed to sort of hot glue a new one in place. Looks ugly from the back, but can't see it from the front. It's a standard 4xAA battery clip. Here's the problem tho: the light sensors really only function well in BRIGHT light, but me being something of a computer nerd shut-in, I don't really "do" bright lights. So I'd like to find a way to get it to work in my house. So - I also own 2 recent Animatronics, both of which have....motion? sensors in them which seem to work fine in the vampire lighting going on in my house, so I'd like to mod the skull to use those instead of the light sensors it has. Probably just going to go ahead and build it into a new frame, as the existing one is molded as all one piece (not the skull- it comes completely off), plus you know - blobs of epoxy everywhere holding wires in place, etc. So my questions: - what part am I looking for here to replace those light sensors? - assuming the power requirements, etc are the same, will that be a 1-1 swap? - if the power reqs are different, what am I looking at here? Here it is working after I rewired the battery clip. As you can see it works just fine under my shop lights, but I have yet to find another spot in the house it works much at all. I owned one of these in the 90s, and I can recall it having the same problem, but we managed to find a good spot back then. https://imgur.com/a/lVv3yDf
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Oct 17, 2022 12:54
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HaB posted:So I think I have come up with a good first project for myself. Gonna need to pop it open and look at the actual circuitry before we can really help, but my money's on it using LDR's (light dependent resistors) since they're dirt cheap. Depending on how it's wired it could be as easy as just adjusting the trip point (by swapping out a resistor, probably).
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Oct 17, 2022 12:57
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Shame Boy posted:Gonna need to pop it open and look at the actual circuitry before we can really help, but my money's on it using LDR's (light dependent resistors) since they're dirt cheap. Depending on how it's wired it could be as easy as just adjusting the trip point (by swapping out a resistor, probably). Ah cool. I will try to break it back down one night this week and get some detailed pics.
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Oct 17, 2022 19:03
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Shame Boy posted:I find it kinda fun to think about designs in a "well what if I want to make a thousand of these?" or "what if I want other people to build this?" way even if I'm 100% sure I'm gonna make one, maybe two (if I break the first one). cruft posted:It's a whole lot of extra work when it's not something you do all the time. But, like Shame Boy said, it's fun; and when it comes to hobbies, my time is worthless. ante posted:Big same. Especially with my work stuff, it's hard to know whether any particular design will end up being a one-off that gets abandoned, or we'll go hard and press the button to get 1000. Splode posted:Yeah that's why I always do it, I can never tell when something is going to get reused later or be a one off, so it's best to assume reuse. I am the opposite of all of this... I tend to treat my projects as if I were Wowbagger from Hitchhikers' wikipedia posted:became immortal due to an accident with "an irrational particle accelerator, a liquid lunch, and a pair of rubber bands", an event which no-one has been able to replicate without ending up looking rather silly or dead (or both).
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Oct 17, 2022 19:04
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Bear Radar manufacturing cost: $289/unit. BOM cost is kicking my rear end, but that was expected. Buying tiny quantities of chips and sensors off Digikey is pretty expensive.
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Oct 18, 2022 20:36
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Is low cost a design goal here or no? Hand assembly would not be too bad and save a lot, also you wouldn't need to do 5/10. Also 3D printing can often be cheaper or free if you ask around locally. Also there's no way you actually need a six layer PCB. All of that is less satisfying then just pressing button and receiving product though
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Oct 18, 2022 20:49
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The design goal is mostly to gain experience outsourcing prototyping/test production of a consumer electronics type product. I don't really care how much the BOM costs, though I felt I should point out why it is so high. Also, the manufacturer is not building the whole device, just the floodlight pcb which is fairly cheap power/analog stuff. So there is only $28 worth of BOM soldered on in China. The other $165 of BOM is stuff I solder on myself, and I don't need to do that in lots of 10. OTOH, I had to buy a stockpile of those sensors to guard against them going out of stock, so it's not like I'm saving any money.
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Oct 18, 2022 21:53
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I did that thing I do sometimes again and found a static CMOS 8051-compatible thing (the NXP CMOS ones run with clock rates down to DC, unlike all the old ones that had dynamic logic) and ran it on my little shift register board simulating RAM/ROM on a much better computer. The 8051 was used in, like, every damned thing from automotive ECUs to appliances for a good quarter century, and versions of it still creep into new designs. I ran the program on top that implements the Sieve of Eratosthenes and computes and prints prime numbers up to 100, the same program I always write. (edit: compiled with SDCC; there are probably other 8051 C compilers out there; this just happens to be the first one I found)  This processor is weird and very, very slow. This program took 281k cycles to finish (8.8cyc/ Stack Machine fucked around with this message at 13:53 on Oct 20, 2022 |
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Oct 20, 2022 03:32
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Could be as simple as de-glitch logic on the reset pin. You've also neatly explained most of the reasons I only use 32-bit ARM microcontrollers these days. Absolutely nothing I build is cost-sensitive enough to deal with that kind of 8-bit aggravation.
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Oct 20, 2022 03:58
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E: whoops! Quote's not edit. But yes 8-bit micros made a lot of sense when it was common to add peripherals. since nobody wants to have to buy 4 EPROMs just to add a lookup table or 4 SRAMs to add a little external memory, or route 32 data bits to their I/O extender, but just buying an STM-32 with extra flash or whatever is really cheap, so I assume this sort of thing is on the trash heap of history for all but a few niche very-cost-conscious applications. And this specific part is even more obsolete since a typical board with a micro on it is probably smaller than 1 or 2 DIP-40s. Also I was editing my post because it turns out this thing is even slower than I counted, because I was counting bytes fetched not instructions. I guess each instruction takes at least one machine cycle, or 12 clock cycles (!). Max clock rate on this thing is 12MHz so it really doesn't do anything in a hurry. Stack Machine fucked around with this message at 13:58 on Oct 20, 2022 |
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Oct 20, 2022 13:52
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Yeah, standard 8051 was 12 clocks/cycles. Dallas had some faster ones with 4 clocks/cycle. High-performance 8051 cores were definitely a thing for while (because the original was so slow). e: EETimes 10.24.2000 Dallas Semi’s souped up 8051 MCU clocks in at 50 MIPS ryanrs fucked around with this message at 17:03 on Oct 20, 2022 |
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Oct 20, 2022 16:58
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Stack Machine posted:Another strange thing about this thing is that the reset pin doesn't seem to just assert a global reset to a bunch of flip-flops or something. It requires the clock to be running while the reset pin is asserted for at least 24 clock cycles, so there must be some state machine or little program or something that runs while reset is asserted to init everything. A chip with an 'asynchronous' reset is likely doing a latch and flip flop chain internally to synchronize and hold the reset internally for enough clocks to go through its deepest logic
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Oct 20, 2022 20:35
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Hm, yeah even the datasheets for the original 8080 and later things like the CMOS Z80s asked that reset be asserted for at least 3 clock cycles and the 65c02 asked for 2. Maybe that's not as weird as I thought. I just happened to notice it because I had to clock this one a lot more times with reset asserted.
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Oct 20, 2022 21:48
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I've been looking at the internals of my cheap Chinese laptop and it's pretty interesting what's left inside  There's this empty 4-pin connector:  Same one from the other side:  And another one, the inside shape seems to be the same, 4 pins:  Any ideas what this could be? Maybe USB-A they couldn't find a spot for? I should've probably measured if it has GND/+5 on the outside pins since I did have it powered on actually. The SSD has an always-on LED for some reason. This triggers me because I remember unsoldeing the led on an ESP32 to minimize power consumption but obviously here it would be negligible  There are also unpopulated pads labeled SATA SSD  But they're mirrored from the other socket, I think that one is B-key?   Anyway, I wonder how much I could pimp this laptop Ideally though I'd find a way to get more battery in there because it's only 28WH.
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Oct 21, 2022 09:03
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mobby_6kl posted:Any ideas what this could be? Maybe USB-A they couldn't find a spot for? I should've probably measured if it has GND/+5 on the outside pins since I did have it powered on actually. Or possibly serial port. When you're working with other companies for GPU, southbridge, audio, etc, it's important to have that low level debug available somewhere.
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Oct 21, 2022 14:59
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I'd assume they just use the same board for several different models (hence the unpopulated SATA port) and those extra connectors are for fans or maybe a line in jack or something like that that's only on the schmick higher end models.
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Oct 21, 2022 15:09
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 could be for fans, I'll see if there's any evidence in bios. There's a shitload of empty space in the chassis so they're clearly reusing the motherboard from somewhere. I'm hoping at least one could be USB though, would be great to hook up a mouse dongle internally, or maybe even an SDR radio or UART or something turbo-nerdy like that. Surprisingly it already came with a 512gb SSD which is plenty for the purposes so I'll probably won't bother with the second m2 socket.
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Oct 21, 2022 19:26
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mobby_6kl posted:There's a shitload of empty space in the chassis so they're clearly reusing the motherboard from somewhere. like the blank switches when you buy a base model car
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Oct 21, 2022 23:15
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There is a room dehydrator running in my basement that is mission critical to prevent the over-abundance of silverfish when it doesn't run for a month. Every week or so, it will light up a LED to indicate that the filter needs to be replaced; it doesn't need it every god drat week though. The issue is when this light is on, it will no longer pull moisture out of the air by turning off the cooling cycle. Is there a way to signal like a momentary switch (like pressing the button) only when the light is on? I do not know how much current is going through the switch so do I need to get a MOSFET to separate the two circuits or is that too much? Electronics is still goddamn black magic to me
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Oct 22, 2022 17:30
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Can you just get something like this? https://www.aliexpress.com/item/1005003057992848.html
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Oct 22, 2022 17:44
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I don't exactly know what solution you have in mind, but I hope it doesn't involve condensate overflowing all over your basement. What are you trying to trigger? Another device to power on? If so this might be helpful: https://dlidirect.com/products/iot-power-relay
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Oct 22, 2022 17:47
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CopperHound posted:I don't exactly know what solution you have in mind, but I hope it doesn't involve condensate overflowing all over your basement. I'm trying to trigger the button on the same device. Maybe a pic will be more helpful  When that LED 1 is pointing at, it means the dehumidifier is not dehumidifying. You need to press the button below it and then the cooling cycle will start; before that it's doing nothing. Pressing the button before the LED lights up seems to not extend the dehumidifying duration; the change filter indicator will always come on. What I am looking for is when that LED comes in, it means the button will do something and linking the LED with the switch seems the most logical. About the condensate, that is taken care of already with a HVAC condensate pump which takes away the condensate to a drain.  ante posted:Can you just get something like this? You know, I keep seeing this and ever since I got over my IoT fears lately, I can see a button pusher useful in many cases (like not having to go down to my server rack to push a power button) Though in the problem I described, I don't know if the LED is lit which means a push of the "change filter" button would do nothing.
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Oct 22, 2022 18:36
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I have an idea of how I would build something to do this, but you might be able to use IFTTT to duck tape a couple off the shelf IOT bits together. Might be worth asking the Home automation thread if they know of any light sensors that might work. Personally, I'd probably rip the thing apart, do some probing around, then jam an arduino in there. Maybe even see if I can skip the Arduino and route that led power directly to the button wires. If you hold the button instead of momentary push, will that light turn off?
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Oct 22, 2022 19:17
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e: Nevermind I misunderstood something in the post
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Oct 22, 2022 19:21
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CopperHound posted:I have an idea of how I would build something to do this, but you might be able to use IFTTT to duck tape a couple off the shelf IOT bits together. Might be worth asking the Home automation thread if they know of any light sensors that might work. That would be my strategy as well, but for someone that describes electronics as black magic, then ripping out a control panel has a high risk of failure and then you have a broken unit, and even if that isn't the case, then the unit is unusable while the project is in progress, which could take a while. So my recommendation would be to tie in discreet building blocks that have a low chance of failure. Here's a light sensor that might work, you'd also need an arduino-alike to tie it into the button presser, either through the internet (very roundabout) or hacking the button presser. Or building your own button presser with a servo motor. https://www.aliexpress.com/item/32820189174.html
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Oct 22, 2022 19:35
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EVIL Gibson posted:You know, I keep seeing this and ever since I got over my IoT fears lately, I can see a button pusher useful in many cases (like not having to go down to my server rack to push a power button) Yeah, until it turns into a pusher bot and pushes you down the stairs.
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Oct 22, 2022 19:37
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That filter thing is just a runtime timer right? Is there any harm in skipping the light sensor and pressing it more often?
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Oct 22, 2022 19:45
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CopperHound posted:That filter thing is just a runtime timer right? Is there any harm in skipping the light sensor and pressing it more often? it looks like it doesn't matter how frequently I push the button . it doesn't do anything except in the case when the led light is on. if i could bypass this timer I would but I don't know if I could trace it back and if it isn't doing something else.
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Oct 22, 2022 20:25
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EVIL Gibson posted:it looks like it doesn't matter how frequently I push the button . it doesn't do anything except in the case when the led light is on. CopperHound fucked around with this message at 20:34 on Oct 22, 2022 |
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Oct 22, 2022 20:31
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Hoorayyyyyy for Cruft! He sent and I received some cool components that I'll be playing around with and learning from! Truly, swap.xls is another goon project that worked as intended and is by far the least terrible swap thing. link: Goon electronics swap sheet
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Oct 23, 2022 01:13
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namlosh posted:Hoorayyyyyy for Cruft! Nice. Those lasers run at 5V, I think. I'd try 3.3V first, though, just to be safe. It's been a while since I tried to use one.
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Oct 23, 2022 01:47
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cruft posted:Nice. Heck yeah they do! I already got one running at 5V… pretty darn cool. And the top that holds the lens is threaded and can be used to focus the beam. Very cool and thank you so much. Anyone want any resistors?  
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Oct 23, 2022 02:35
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I really thought hand-soldering a SC-70 (SOT323) package was going to be atrocious once I saw it, since it's only 2 mm long and 1.5 mm wide, with 3 legs on one side. But I had way more problems hand soldering a FFC connector because the legs just took NO solder, so drag soldering it created like 20 bridges even with tons of flux, the legs really sort of 'scraped' the solder off the hoof tip and then it had nowhere to go. Also I've been watching through this series which is a ton of fun, guy is building a 8-bit CPU up from 5v logic: https://www.youtube.com/watch?v=3iHag4k4yEg There's like 100+ videos in the playlist. Rescue Toaster fucked around with this message at 15:13 on Oct 23, 2022 |
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Oct 23, 2022 15:11
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Rescue Toaster posted:I really thought hand-soldering a SC-70 (SOT323) package was going to be atrocious once I saw it, since it's only 2 mm long and 1.5 mm wide, with 3 legs on one side. For the solder issues, use less solder maybe? Every time I watch someone solder something with a fine pitch I’m amazed at how little solder they put on the tip for transfer to the joint, which is also funny because it’s the opposite of what you’d do for through-hole. I’m just guessing from watching tons of videos though lol I just subscribed to that same guy yesterday! I’ve been watching Ben Eaters vids and kind of can’t believe this guy hasn’t been recommended before. Thx google algorithm for sucking. Are those black things those old time resistor networks? I didn’t think they made those anymore
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Oct 23, 2022 16:04
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namlosh posted:For the solder issues, use less solder maybe? Every time I watch someone solder something with a fine pitch I’m amazed at how little solder they put on the tip for transfer to the joint, which is also funny because it’s the opposite of what you’d do for through-hole. I’m just guessing from watching tons of videos though lol Yeah the idea with a hoof tip though is it can continue to hold large amounts of solder as you drag it across, as long as there's plenty of flux it should sort of naturally only deposit enough. I've had great luck in the past, even with 0.5mm pitch parts, but for some reason this 0.65mm connector just wanted to pull extra solder off the hoof, I guess. Those are resistor networks, yeah. You can still get them, those would be probably 9-SIP packages with 8 resistors. They are great for LED bars like he uses everywhere.
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Oct 23, 2022 16:10
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