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Ambrose Burnside posted:i want an excuse to buy a lil e-paper screen and am considering tackling a small arduino-based e-reader as the excuse; ran into this open-source design for one, and was tickled mightily by the dr bronner's-calibre tomes of text worked into the pcb silkscreen Man, here I was thinking I was clever for marking each logical section of my board with boxes and labels 
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Feb 23, 2020 22:06
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Sagebrush posted:Molex Micro-Fit Seconded. We've been using them for the interconnects between aircraft cabin LED tubes for quite a while now and they're fantastic. A little fiddly to crimp with anything that's not the actual Molex brand tool because the contacts are kind of frustratingly small, but most "universal" Molex-style crimpers with at least one tiny jaw should do the job. The one that csammis posted above looks like it'd probably take care of it and it doesn't cost $400.
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Feb 23, 2020 22:36
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Shame Boy posted:Man, here I was thinking I was clever for marking each logical section of my board with boxes and labels These days I rarely even put the designators on. Why does everything have to be so drat small
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Feb 23, 2020 23:27
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Sometimes little bits of my designators show through amid the field of vias
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Feb 23, 2020 23:41
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Micro fit 3 work well, are common as dirt, are high current (~8A), come in wire-to-board and wire-to-wire, have off-the-shelf cable assemblies, and tooling is extremely cheap ($140 for Molex's low-end hand tool, $375 for the normal one). The only bad thing about them is that they're fairly large.
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Feb 24, 2020 00:01
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Is there such thing as a JST variant that has both wire-wire and wire-board connections on one standard?
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Feb 24, 2020 02:36
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What are the substantive differences between the seeed respeaker raspi 4-mic array ( https://www.seeedstudio.com/ReSpeaker-4-Mic-Array-for-Raspberry-Pi.html ) and the 4-mic linear array? ( https://www.seeedstudio.com/ReSpeaker-4-Mic-Linear-Array-Kit-for-Raspberry-Pi.html )? From what i can tell: the linear array offers hardware-driven echo cancellation + audio output and the base model doesn't, the base has an LED ring that the linear doesn't, and the linear breaks out the array as a strip so the form factor's different. Am i missing anything big?
Ambrose Burnside fucked around with this message at 04:46 on Feb 24, 2020 |
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Feb 24, 2020 04:44
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Ambrose Burnside posted:What are the substantive differences between the seeed respeaker raspi 4-mic array ( https://www.seeedstudio.com/ReSpeaker-4-Mic-Array-for-Raspberry-Pi.html ) and the 4-mic linear array? ( https://www.seeedstudio.com/ReSpeaker-4-Mic-Linear-Array-Kit-for-Raspberry-Pi.html )? From what i can tell: the linear array offers hardware-driven echo cancellation + audio output and the base model doesn't, the base has an LED ring that the linear doesn't, and the linear breaks out the array as a strip so the form factor's different. Am i missing anything big? Both of those links are 404'ing, even if I google for it and click the link there, so who knows 
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Feb 24, 2020 16:09
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That's bizarre, I think they updated their website and broke all their old links in the time between me posting and someone replying. these oughta work: https://www.seeedstudio.com/ReSpeaker-4-Mic-Array-for-Raspberry-Pi-p-245.html https://www.seeedstudio.com/ReSpeaker-4-Mic-Linear-Array-Kit-for-Raspberry-Pi-p-132.html
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Feb 24, 2020 21:50
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i didnt eat breakfast yesterday and accordingly became fixated on the aesthetic of a dystopian-near-future renegade welder (or maybe water electrolyzer, arc furnace operator, etc) stealing Fat Current from streetcar routes using a spring-loaded tap wedged between the supply wire and the ground track return, and the work in between as the load, paying some street urchin in an improvised arc flash suit to run back and forth and remove/reinstall it every few minutes to let traffic pass w/o noticing its a very stupid thought to get caught up on but: i wonder if anybody's ever done sth like that without dying in the process Ambrose Burnside fucked around with this message at 16:39 on Feb 25, 2020 |
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Feb 25, 2020 16:28
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You should meet the megavolt addicts. Building ever larger Tesla coils just to play their MIDI files with the power of Zeus. Back when I was into it, people bid on pole pigs (residential transformers) that utility companies were scraping out. They would wire their house mains to the output of one and bam, 14,000V, 12kW primary.
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Feb 25, 2020 17:00
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There was a guy in Europe or something that modified a car to be able to do that I thought
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Feb 25, 2020 19:22
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controversial statement incoming, but i need to speak my truth: “henrys” are a really stupid name for a scientific unit, and they set a bad precedent for naming things after discoverers arrogant enough to have a first name for a last name
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Feb 25, 2020 22:47
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Ambrose Burnside posted:controversial statement incoming, but i need to speak my truth: You pretty much never need to deal with whole H Henrys so I just call them muhs / uhs / nuhs / puhs
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Feb 25, 2020 22:51
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Inductors are my least favourite component so I'm glad they get the silly units
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Feb 25, 2020 22:53
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Shame Boy posted:You pretty much never need to deal with whole H Henrys so I just call them muhs / uhs / nuhs / puhs that's also a minus and not a plus, if henrys had a smaller + more day-to-day base unit we'd at least get some laughs out of "Mega Henrys" and so on
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Feb 25, 2020 23:02
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Ambrose Burnside posted:that's also a minus and not a plus, if henrys had a smaller + more day-to-day base unit we'd at least get some laughs out of "Mega Henrys" and so on microHenries is pretty good
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Feb 25, 2020 23:03
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I scored a BK Precision 3030 function generator from the trash at my university. It works fine except the output jack is scorched and the output amplifier has a bunch of overheating transistors - the signal up until the power amp is perfect. It came from the lab of the guy who does plasma poo poo so I imagine someone hooked it up to something high voltage the wrong way. I was going to replace all the diodes and transistors in the whole output amp. It's mostly okay because it's all common poo poo like 2N3904s, 2N3906s, and 1N4148s that I have bags of already. The problem is that the power transistors Q36 and Q37 that make up the push-pull output are old things, 2N2219 and 2N2905 respectively, that I can't find for sale on Digikey and therefore may as well not exist anymore for me. What are the chances like for a circuit like that that I can just plop in any similar pair of NPN and PNP power transistors I want? They seem like there's no fancy biasing and that they just need to be be a bit beefier than the 3904s and 3906s elsewhere in the circuit. For instance, I think I have some 2N2222s and 2N2907s laying around that have similar power and current ratings and come in metal cans as well, maybe those will work?
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Feb 25, 2020 23:34
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BattleMaster posted:What are the chances like for a circuit like that that I can just plop in any similar pair of NPN and PNP power transistors I want? They seem like there's no fancy biasing and that they just need to be be a bit beefier than the 3904s and 3906s elsewhere in the circuit. For instance, I think I have some 2N2222s and 2N2907s laying around that have similar power and current ratings and come in metal cans as well, maybe those will work? If it doesn't work, it goes back in the trash. What do you have to lose besides time?
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Feb 26, 2020 04:00
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BattleMaster posted:I scored a BK Precision 3030 function generator from the trash at my university. It works fine except the output jack is scorched and the output amplifier has a bunch of overheating transistors - the signal up until the power amp is perfect. It came from the lab of the guy who does plasma poo poo so I imagine someone hooked it up to something high voltage the wrong way. I think mouser has those old FETs but yeah I suspect you can just substitute a similar part and see if it works
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Feb 26, 2020 04:03
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BK Not-as-much-precision
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Feb 26, 2020 04:54
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I bought some grab bags of weird old components off ebay a while ago and I think I got some of those specific transistors if you want em'. I'll check when I'm home later. I also got one of those old EPROM's with the window that I'm just keeping as a display piece because they look real cool 
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Feb 26, 2020 15:51
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BattleMaster posted:
Both those things listed are cheap on ebay for old stock, if you want to be lazy.
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Feb 26, 2020 17:11
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Looks like the ones I had in that grab bag are actually 2N4something, oh well. I'd just get the new old stock ebay ones personally 
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Feb 26, 2020 19:19
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Shame Boy posted:I bought some grab bags of weird old components off ebay a while ago and I think I got some of those specific transistors if you want em'. I'll check when I'm home later. Those are also empirically very cool since you actually use light to erase the memory. It’s from the fun days where everything is still very analog.
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Feb 26, 2020 19:38
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Shame Boy posted:Looks like the ones I had in that grab bag are actually 2N4something, oh well. I'd just get the new old stock ebay ones personally Aww, oh well. On ebay the shipping from the US to Canada is immense for some reason and I'm not sure if the stuff from China will be weird counterfeits. Maybe I'll try buying some if I can't finagle a close-enough replacement.
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Feb 27, 2020 05:26
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Doing some MacGyver poo poo today, ignition wire on my ebike just broke apart from the crimp connector (metal fatigue I guess), and I didn't have my soldering iron on me but I keep a loop of solder in my wallet, so I managed to solder it back together with a single match from a matchbox:
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Feb 27, 2020 23:45
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drat nice work mac
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Feb 27, 2020 23:51
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Zero VGS posted:Doing some MacGyver poo poo today, ignition wire on my ebike just broke apart from the crimp connector (metal fatigue I guess), and I didn't have my soldering iron on me but I keep a loop of solder in my wallet, so I managed to solder it back together with a single match from a matchbox: King poo poo i remember reading sth from a corrections officer about how he'd always overlook one guy's contraband during cell searches b/c he did electronics repair for everyone else in there and the contraband was just his tools, soldering small electronics back together with a fuckin plastic blowpipe (a v primitive directional torch that's functionally just you blowing air with a narrow pipe through an open flame) fuelled by hand sanitizer Ambrose Burnside fucked around with this message at 07:38 on Feb 29, 2020 |
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Feb 28, 2020 00:01
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Zero VGS posted:Doing some MacGyver poo poo today, ignition wire on my ebike just broke apart from the crimp connector (metal fatigue I guess), and I didn't have my soldering iron on me but I keep a loop of solder in my wallet, so I managed to solder it back together with a single match from a matchbox: Holy poo poo 10/10
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Feb 28, 2020 07:12
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Splode posted:Holy poo poo 10/10
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Feb 29, 2020 07:09
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I'm using a circuit like this to drive a 12V fan, the 12V supply and gate drive signal is coming through a connector from an external board. Should there be a capacitor on this board for the 12V supply or is this ok as is? The fan datasheet doesn't really give me much useful info about this other than that it draws 100mA max. 
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Feb 29, 2020 08:36
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MaxxBot posted:I'm using a circuit like this to drive a 12V fan, the 12V supply and gate drive signal is coming through a connector from an external board. Should there be a capacitor on this board for the 12V supply or is this ok as is? The fan datasheet doesn't really give me much useful info about this other than that it draws 100mA max. Capacitors on power supplies are there to filter high frequencies. That is, if there's a sudden increase in current, they absorb the dip that would otherwise show up on the rail (in this case, 12V). This is useful because unpredictable things can happen when your power supply is noisy, but it mostly impacts chips that handle data. Off the top of my head, the likelihood and cost of browning out a fan for an instant are pretty low. If it's a computer fan, those are already intended to be run at the end of a long wire. If it's a brushed DC motor, voltage is just analog speed control anyway.
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Feb 29, 2020 16:39
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What's on the external board? The fan doesn't care about brownout or noise, but whatever's driving the fan might not like the high frequency switching spikes (assuming you're using PWM) very much. Probably doesn't matter as long as the external board has filter caps though.
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Feb 29, 2020 22:48
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MaxxBot posted:I'm using a circuit like this to drive a 12V fan, the 12V supply and gate drive signal is coming through a connector from an external board. Should there be a capacitor on this board for the 12V supply or is this ok as is? The fan datasheet doesn't really give me much useful info about this other than that it draws 100mA max.
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Mar 2, 2020 12:10
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I'm screwing around with some old Soviet-surplus IV-11 VFD segmented number tubes and getting some weird results. I can't read the datasheets so I'm going off https://www.instructables.com/id/OpenVFD-6-Digit-IV-11-VFD-Tube-Clock/ for the pinout, specifically this bit: quote:- Pin 1 and 11 belong to the heater (cathode). Either pin can be tied to ground (0V) and the other one receives the cathode voltage of around 1.5 volts. The latter voltage needs to be on all the time to make segments glow  but my lil breadboard circuit (12V1A wall-wart supply -> boost + buck converters -> tube pins) isn't quite following suit. pins 1/11 work as described, but the anode pins light up without needing to have the grid pin powered, and the grid pin itself doesn't seem to do anything beyond do "bad stuff" when supplied with 30V- the tube itself makes noise and an orange??? glow can be seen, ticking on and off audibly at what i'd guess is 60hz. when the grid pin is powered the anodes don't light up as expected. needless to say I'm avoiding doing the Bad Grid Pin Thing for the tube's sake. the tube appears to function properly when the grid pin is ignored entirely, but for all I know they could be operating in a state that's horrible for the tube's longevity. what's the deal? i usually bank on grounding problems. it's always the goddamn ground. Ambrose Burnside fucked around with this message at 23:12 on Mar 4, 2020 |
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Mar 4, 2020 23:07
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Post your schematic
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Mar 4, 2020 23:19
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There is a link to a datasheet on the instructables page you posted: http://www.tube-tester.com/sites/nixie/dat_arch/IV-11_2.pdf
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Mar 4, 2020 23:25
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Armacham posted:There is a link to a datasheet on the instructables page you posted: http://www.tube-tester.com/sites/nixie/dat_arch/IV-11_2.pdf ...gdi i saw this but got confused 'cause idk the tube datasheet conventions and disregarded it b/c i saw "12th short pin" and assumed it couldn't possibly apply to my 11-equal-length-pin tube ...but if the 12th short pin is actually just the gap in the ring of pins, and i connect things accordingly, i.e. the reverse of what i initially did, all is good and it works properly whoops
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Mar 5, 2020 01:24
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Zero VGS posted:Doing some MacGyver poo poo today, ignition wire on my ebike just broke apart from the crimp connector (metal fatigue I guess), and I didn't have my soldering iron on me but I keep a loop of solder in my wallet, so I managed to solder it back together with a single match from a matchbox: This is impressive as hell but everybody is ignoring this Zero VGS posted:but I keep a loop of solder in my wallet,
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