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armorer posted:I need a single normally-off, momentary-on push button switch to control two completely separate battery powered circuits. I've been looking at DPST and DPDT switches on mouser, but the schematics in the datasheets look like the circuits are crossed, even if maybe just sharing a ground, when the button is pressed. Does something exist like what I'm looking for? I also need it to be low profile, and I'm thinking maybe I'll just 3d print an enclosure for two SPST buttons and put a plate over the top of them so they are pressed together. This is for a costume, so, low order quantity and all that. What do you mean by it looks like they are crossed? I'm looking at DPST datasheets and I'm seeing stuff like this:  I would assume that the dashed line means they are physically connected by not electrically connected.
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Oct 3, 2019 16:16
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Splode posted:well you could replace them with diodes that don't emit light? Technically all diodes emit light.
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Oct 10, 2019 02:47
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General_Failure posted:Ohhhh. Sorry. Yeah I've not scraped eBay before. Just other things I can't seem to recall. Sorry. Is it possible to set up an RSS feed of sales on eBay? Just a thought anyway. Never tried that. You can save a search on ebay and it will periodically email you with new items that come from that search.
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Oct 10, 2019 06:17
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Der Shovel posted:Crossposting from the physics thread. Have you considered just spending 40 bucks on a magnetic stir plate and a bunch of stir bars? Unless you really just want to make something.
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Oct 14, 2019 23:01
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Those resistor arrays are really nice. There's a dot on one of the pins that to indicate which is common to all the other pins. You just tie that to the 5V coming from the controller port. Edit: Though he must be doing some voodoo on the other side of that prototyping board. You won't be able to do what he did with it right next to the chip like that on a breadboard. With a breadboard you'll have to either do individual resistors to the 5V rails of your board, or set a resistor array off to the side and run wires to the correct pins. Cojawfee fucked around with this message at 02:27 on Oct 19, 2019 |
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Oct 19, 2019 02:21
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If you are sticking with the breadboard, run the 5V from the controller port to the red rails and run the GND from the controller port to the blue rails. Then wire the VCC and ground pins from the chips to these rails. This also allows you to just connect the resistors straight into the 5V rail and the other side of the buttons to the ground rail.
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Oct 19, 2019 04:08
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To be faaaaaaiiiiir, some of that is iron eating bacteria.
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Oct 21, 2019 03:17
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Do those nixie tubes count the number of times you've thought about finishing a project but didn't?
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Oct 28, 2019 21:37
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Sagebrush posted:that guy was talking about controlling 1500 amps with 25 arduinos uno The Arduino website clearly states quote:Arduino is an open-source electronics platform based on easy-to-use hardware and software. Arduino boards are able to read inputs - light on a sensor, a finger on a button, or a Twitter message - and turn it into an output - activating a motor, turning on an LED, managing 30 other arduinos to control 60,000 neopixels in a display you have no reason to create.
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Nov 2, 2019 03:10
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There is also this thing from Sparkfun if you want a ready made thing. https://www.sparkfun.com/products/11801
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Nov 5, 2019 21:50
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I'm a bit confused about what I'm working with here. I bought some switches for a project I'm working on. The actual button is removable and there is a light below it. When I bought it on Aliexpress, it said it is an LED switch. When I took out my multimeter to check which direction the diode goes, it lights up in either polarity. Both directions have a forward voltage of 2.9 volts and light up the light. Is there some sort of magic going on inside this thing? The switch says 12V which I am assuming is the max voltage of the light or something. The switch itself is rated for 250V 5A, so I have to assume the 12V refers to the LED. So is there some sort of circuitry in there that allows it to be bidirectional? This is what the actual light looks like  Is this a normal LED? Do I need a resistor in series with this?
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Nov 13, 2019 21:55
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hifi posted:They make bipolar LEDs that are just 2 diodes in parallel pointing in opposite directions. If it's intended for AC that makes a lot of sense. Ah, ok that makes sense. I did a bit more investigating and it does seem that one of those things lights up in one direction, and the other lights up in the other direction. Thanks.
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Nov 14, 2019 20:08
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Splode posted:They've tried. I had one try and tell me that what our multimeter needed was a scoreboard where people could compare measurements ??? Hope that comes with a lifetime warranty. "The meter was reading about 50 amps until the thing melted, that should count for the leaderboards."
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Nov 26, 2019 21:22
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I've been comparing the two and it seems like the Siglent is nice but if you want the logic analyzer, you're paying 400 bucks on the siglent vs 200 with the Rigol.
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Nov 29, 2019 04:16
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Also, with the auto wire strippers, I have issues with some kinds of solid core wire. It will cut the jacket, dig into the wire, and then the push the jacket back on the wire instead of removing the jacket on the part you're trying to strip.
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Dec 1, 2019 02:55
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moron izzard posted:those listings are someone reselling them for $40 and $30 respectively 200 bucks for 12 computers seems like a decent deal.
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Dec 1, 2019 04:32
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Home made PCB sounds fun as small project to see how things can be done, but it just seems like it's better to just get a professionally made board that will be better than anything you can do.
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Dec 1, 2019 23:05
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How many digits? You could also just use a shift register for the decimals of each digit.
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Dec 4, 2019 17:38
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If an alkaline AA has about 3000 mah, and that thing normally lasts 12 hours, then that's about 250 mA per hour. You could stick four CR2032 coin cell batteries together to get 12 volts and it should last about an hour. I don't know if that's how longevity of batteries, works, I'm not a battery guy. But you could just stick four coin cells together and see how long it lasts with that. Get two of these guys, put them in series and you have 12 volts. Cojawfee fucked around with this message at 06:04 on Dec 11, 2019 |
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Dec 11, 2019 06:00
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I guess that's why my professor said mixed signal people get paid the big bucks.
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Dec 19, 2019 23:42
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This definitely seems like one of those projects where if you don't already know how to do it, it's never going to work the way you want it to.
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Jan 12, 2020 01:00
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You could just buy an existing brushless fan, take it apart, and remove the controller and put in what you want. I had one that was stuck so I ripped it apart. I removed the sticker on the back, pried out a piece of rubber and then there was a retaining ring holding the fan into the housing. It was broken, so I removed it and the fan blade part came out the front.
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Jan 13, 2020 01:30
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You're not going to create the final product while figuring things out. You start with a prototype, which is likely going to be a fan you buy and rip apart. You get the prototype to do what you want, and then you find a manufacturer to get the parts you want.
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Jan 13, 2020 20:01
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mobby_6kl posted:Ok stupid question but what's with the horrible little fibres in some headphone cables? I've been trying to solder on a new connector and it's pretty much impossible to do cleanly because they will neither solder on not burn off so it's a huge mess. Are they yellow? It might be kevlar to prevent the cable from being stretched apart. I know fiber optic cables have that.
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Jan 15, 2020 20:58
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I built that kit back in the summer, it was really fun.
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Jan 16, 2020 06:09
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I have some of the push button ones and you just need the red sized female crimp connectors. The connectors I got had a little dimple on them that made it impossible to remove from the button, which maybe is the point, but it also ripped the tab out of the button when I tried to remove one, so I just hammered the dimple down. The connector itself held on just fine. If you can't figure out what size the switch is, you'll just have to buy all three sizes of female connectors and see what works. The toggle switches I got just have screw terminals.
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Jan 22, 2020 18:21
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What do you want to do?
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Jan 26, 2020 19:47
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The switch works by connecting one of those posts to the other one. You could just solder some wires to those two posts but there are a few things you need to worry about. I would assume that if it is a decently made battery pack, the power from the batteries isn't going through the switch itself, and that the switch powers a relay or a mosfet or something that that is what sends power from the batteries. So hopefully that switch doesn't have all the electricity going through it. And you don't want to modify that thing in any way where the battery power goes through your added switch. Also, if you don't really know what you're doing, you might not want to mess with soldering on that with the batteries connected. One thing you could do is figure out what size the posts on that switch are and then find the right size of these type of connectors to connect to the post. But if you don't really know what you're doing, you shouldn't mess with the innards of anything that contains 18650 cells, they aren't meant to be messed with by consumers.
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Feb 1, 2020 07:45
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I think it's just stage light gels.
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Feb 7, 2020 17:40
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Someone was doing something similar to that in the arduino thread and seemed to have nothing but problems with it.
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Feb 7, 2020 18:37
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Is there a chance you can throw a tiny breadboard in the box as well? Get a 74**08 (HC or LS depending on your logic level) and connect the switches to the inputs of an AND gate, and the output to your GPIO.
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Feb 13, 2020 02:29
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Splode posted:Float one key at 100V relative to the other so if someone touches both at the same time they die. Simple! This is the answer. You just need two level converters.
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Feb 13, 2020 07:08
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If you have s bunch of LEDs on their own GPIOs, you can swap that out for a shift register and that gives you more GPIOs for switches.
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Feb 13, 2020 17:22
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555 timer will do it. In monostable mode you can decide how long the pulse stays high after you turn the switch, so you won't need spring return switches. You could turn one, run to the other one and turn that one but the first one will be back to off by then. With a 100uF cap and a 10k potentiometer, you could set the pulse width from 0.01 seconds to 1.1 seconds.
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Feb 14, 2020 02:12
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longview posted:For your typical 16/19mm automotive push button switches (the kind with cool ring-lights built in) they make special connectors like this: I've yet to find a single one of those that fits the connector pattern and size of the switch FISHMANPET has.
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Feb 22, 2020 01:17
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A decent chinese soldering kit (anything that comes with an iron that controls temp) is going to come with solder wick and a solder sucker.
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Mar 5, 2020 22:10
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I bought a lattice card to check it out but their website never sent me a license to actually use their software. So I returned it and night a different thing.
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Mar 7, 2020 19:03
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Would hot glue work for covering the pins? Poking at it with alcohol and cotton swaps allows you to remove it to access the pins and then just glob more on when you're done.
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Mar 14, 2020 20:17
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Is that even possible? If you load in data while it is shifting out, you'll just lose the old data and get right side of the new data.
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Mar 15, 2020 17:47
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| # ¿ Apr 27, 2024 10:08 |
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Matt Parker's latest book has a lot of number overflowing incidents. His book is itself an overflow error.
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Apr 2, 2020 21:21
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