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JawnV6 posted:What kind of RFID tag though? NFC only works out to 20 cm, they can't waggle the 'detector' around that much of the room. I think HF only goes 3 feet? Even those are assuming alignment. He said that instead of aiming the ghost detector around the room, he had an alternate idea to just go up and touch specific objects and "test" them. RFID would work fine for that. JawnV6 posted:Also this, the switches toggle states. They're not 'pull low to activate' That was the desired behavior, from my reading of his post. I didn't debounce the buttons, though, that's true. You gotta be fast
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Jul 21, 2017 00:36
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So my house lights use an unencrypted u authenticated protocol to set dim levels If I change house number to, say 10, I gently caress with my neighbors They came with the house and are wired in with 433.92 MHz wireless controllers, and are considered pretty high end which means the wall switches cost 125 earth dollars to replace
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Jul 21, 2017 00:41
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Malcolm XML posted:So my house lights use an unencrypted u authenticated protocol to set dim levels Welcome to the Internet of poo poo
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Jul 21, 2017 01:09
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Malcolm XML posted:So my house lights use an unencrypted u authenticated protocol to set dim levels Same.
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Jul 21, 2017 01:28
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Neat tip regarding those TS100 soldering irons: old ThinkPad power bricks fit and power them perfectly. These were the bricks with the small diameter barrel plug, so 2 generations old by now. Think the Pentium III, Windows 98 era. You might have one in a drawer somewhere, and third party ones are dirt cheap. Stabby McDamage fucked around with this message at 03:00 on Jul 21, 2017 |
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Jul 21, 2017 02:51
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Splode posted:Welcome to the Internet of poo poo These are pre iot garbage lights Poor security has always been an issue I can buy 500$ of kit to make it cloud connected though Or.hack it with an arduino and a transmitter that costs more than the arduino
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Jul 21, 2017 08:46
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Stabby McDamage posted:Neat tip regarding those TS100 soldering irons: old ThinkPad power bricks fit and power them perfectly. These were the bricks with the small diameter barrel plug, so 2 generations old by now. Think the Pentium III, Windows 98 era. Seconding this, I bought one of those irons after seeing it in this thread just to play with, and found out the power brick to my old Lenovo from almost a decade ago fits it perfectly (though the cable was all ratty and frayed). Just because I have too much time on the weekends I took the actual power supply out of the brick and found it really well shielded with nothing live accessible without disassembling the metal, so I attached it to a wooden board/faceplate thing with a bent metal bracket on the live side just in case, then desoldered the old cable and hooked it up to a switch and barrel jack socket and LED mounted on the faceplate to make a basic "power supply" for it. It outputs 19.5V and handles the current of the thing heating up without even getting warm. I just wish I hadn't hosed up half the holes in the wood so it actually looked good instead of the weird offset crap it looks like now 
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Jul 21, 2017 14:26
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Speaking of which, I've been meaning to pick up two of those cheapo usb soldering irons to use as SMD tweezers http://hackaday.com/2016/12/07/turn-cheap-usb-soldering-irons-in-to-tweezers/
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Jul 21, 2017 14:31
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A friend of mine wanted to learn more about electronics so came up with a weird project for something to build as an excuse to learn and buy some new toys. His idea was a hardware random number generator. In his head it would be a self-contained box with a display and buttons so you could input what you wanted and it would spit out a result. You know, "roll me 4 6-sided dice and give me the total after ignoring the lowest die, then do that 6 times". This would obviously require a fairly complex input system so he soon decided to stick a bluetooth module in it and have it send random data to your smartphone instead. As he's a programmer this also gave him an excuse to learn to code on Android phones. I keep telling him to make a website detailing what he's done so other people on the spectrum can marvel at how mad he is, but here's a taster just to add some home-grown stuff to the thread. It's not finished yet as it is missing the top fluid module and the bottom panel, but it's getting close. His Turing-complete dice-rolling code allows you to do the aforementioned D&D character sheet generation, as well as stuff a lot more esoteric such as "roll a pi-sided dice 8.6! times, and assign each value to a fruit. Tell me how many 'oranges' I got". It's beyond crazy. Here it is turned off. That grid on the top is a bank of RGB LEDs with a small cut-out in the middle that allows a camera lens to look through. The finished article will have a fluid-filled cavity on top with reflective material in it as the primary random data source. You shake the whole thing and the swirling liquid with glittery bits in it will be lit by the LEDs and the camera will sample that as the input stream of his random number generator. Then further hardware and software goes to work to make that poo poo as random as possible.  He tells me that his data streams pass more randomness-testing tools than anything else he can find (if I remember him correctly!) and goes on at length to me about tons of things I don't have a clue about like chi-squared and TestU01. Here it is with the LEDs going through a colour pattern. It is crazy bright running off 4xAA batteries, and he only runs them at 10% or something. It has completely zero power usage when not being used as he has physical sensors that wake it when you shake it. I think they are mercury switches or something similar. USB port on the side if he needs to update the firmware and bluetooth to communicate to a smartphone to transmit the random data.  He also bought himself a cheap (well, $800 or so) Chinese 3040 desktop 4-axis CNC milling machine that he used to mill out those acrylic casings. He had to do a lot of tweaking of it to get it fairly accurate and level so if you're thinking of buying something like that he has a lot of pointers on how to make it better without just spending more on a better machine to begin with.
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Jul 21, 2017 17:40
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Get him into the forums if at all possible. He sounds like he'd for right in.
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Jul 23, 2017 13:49
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Yeah I'd be interested to know how he implemented the random number generator part in hardware since I'm always toying around with radioactive ones or sampling the noise from a reverse-biased transistor or things like that.
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Jul 23, 2017 16:44
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What relation does the material Tg of the PCB material have in regards to reflow oven temperatures? The Tg I see offered at services is like 140-150°C and high Tg more like 180-190°C. How I understand reflow ovens, they go up to 220°C?
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Jul 24, 2017 23:38
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ate all the Oreos posted:Yeah I'd be interested to know how he implemented the random number generator part in hardware since I'm always toying around with radioactive ones or sampling the noise from a reverse-biased transistor or things like that. tbh there are only a couple sources of true randomness and they all boil down to thermal or quantum effects or some mixture of the two seeing as it's called "twin avalanche" i suspect it's an avalanche diode possibly constructed from transistors
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Jul 25, 2017 02:42
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So i'm hoping a goon might be able to help me with some insight into an issues im having. I have a pi zero with an explorer phat on top. The explorer has 2 h bridge outputs that run at 5v and 200ma. I am trying to make a small roving robot with motors attached to this. This is where my problem starts, I'm using a lego track base right now but the lego motors are 9v not 5v so they are more or less out of the equation (someone ran them at 4.5v which gave a far slower rotational speed and upped the current draw to 280 ma, so beyond what I can supply) The motors I have been looking at are 6v motors but many people use them at 5v. I need them to be able to drive my little rover around at a decent speed, not blazing fast. There are multiple versions of these motors with varying gear ratios all the way up to 1000:1. My issue is I have no idea how to tell what motor I need. I know the lego motor can move the rover (thought a bit fast) and that outputs 0.3kg cm of torque at its normal operation current and about 400rpm. Assuming the motor is running at 0.3kg cm of torque then there is a motor which (at 6v) can output 0.3kg cm of torque at 70 rpm, this would (on my rover) be roughly 6 meters per minute, which is possibly not absurdly slow (might be too slow, would like input here too). However I can get a motor which runs at 400rpm but it only puts out 0.1 kg cm of torque. I'm basically stuck and cannot decide what the right motor to buy would be. The best idea I have so far is test the lego motors current draw while moving the rover around, if it is drawing near its normal operating current then I know it will be at 0.3 kg cm. Hopefully it will be using below that which means I can use the faster motor. Of course its entirely possible none of the motors i'm testing will work and I have to go up to 9v motors, which I suppose is an option but would require a new h bridge and a separate power supply (or something to step 5v up to 9v). Any help or insight appreciated!
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Jul 26, 2017 04:48
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Kea posted:However I can get a motor which runs at 400rpm but it only puts out 0.1 kg cm of torque. I'm basically stuck and cannot decide what the right motor to buy would be. Is gearing this one down to a lower RPM/higher torque externally an option? It might be easier to solve for your speed/torque with gear or belt ratios than it is to find a 5-6v motor with a built-in gear box that hits the torque and rpm in your ideal range.
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Jul 26, 2017 05:52
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yeah custom gearing* on that 400rpm 0.1kgcm motor sounds like the solution that's most likely to work, though obviously making your own gearbox* is going to be a bit of a pain. *gears or belts would both work I would personally have found a 9V or 12V H-bridge from the start, but if you've already found your components it doesn't really matter. 6m per minute sounds way too slow though. Whatever you decide on, please keep the thread updated, I have a similar project in mind and I'd love to see how you go about doing everything.
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Jul 26, 2017 05:59
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Splode posted:yeah custom gearing* on that 400rpm 0.1kgcm motor sounds like the solution that's most likely to work, though obviously making your own gearbox* is going to be a bit of a pain. Well i have an interface to lego right now and an assortment of lego gears, i could do a 2:1 in that I suppose. The other option is grabbing a 9v capable H bridge (found one, £2 + shipping) and stepping up my power supply (5v) to 9v. I'm sure there are multiple ways to do this, though it would mean I have to deal with 2 different voltages which is a bit of a pain. The wheel im driving has a circumference of roughly 8cm so if I did a 2:1 reduction I would be sat at around 16 m per minute, or 10 seconds to travel 2.6 m which doesn't feel too bad? edit: for a little info on my project, I'm using a raspberry pi zero as the brain connected to a 5v USB power pack, gives 4000mah at up to 2a. I have an explorer phat attached which is a premade thing that breaks out the pins from the pi zero to a double h bridge, 4 5v inputs, 4 5v outputs and 4 analog inputs. So far I have loaded raspbian onto the pi and used a USB wifi connector to get it on the network. I,m remoting into it (via remote desktop) so I don't have to hook up a keyboard, mouse and screen every time I need to do something. I have written a basic python motor test gui. Hoping to change it so I can control it without needing to remote in as well as increase functionality by adding voice recognition, an inbuilt camera, possibly various sensors. Also plan to add wireless charging to the rover and would love to be able to make it find its way to its charging pad. I will probably think of more things to add as I go but I'm just adding one thing at a time. Kea fucked around with this message at 06:15 on Jul 26, 2017 |
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Jul 26, 2017 06:06
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Stepping up the voltage isn't worth the trouble in this case. Using the lego gears sounds like your best bet, that's nice and easy.
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Jul 26, 2017 07:57
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Splode posted:Stepping up the voltage isn't worth the trouble in this case. Thanks for the insight (as well as ickna) this is what I will probably go with, first I'm going to check the load on the lego motor so I can get a rough idea of how much power its pulling. If it turns out its pulling well above its rated just to move the vehicle then I know that gearing the 6v motor probably wont do the trick. I will hold the 9v idea in reserve for now.
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Jul 26, 2017 12:32
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Are all electronic CAD applications as cumbersome to use as KiCAD?
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Jul 26, 2017 14:26
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Combat Pretzel posted:Are all electronic CAD applications as cumbersome to use as KiCAD? KiCAD is one of the easiest ones I've used so... yes. The real fancy paid pro poo poo like Altium has a better workflow in my opinion but also several orders of magnitude more complexity and things to tweak and fiddle with If you just want something incredibly stupid-simple you can try Upverter, it's browser-based and free and I made my first actual board with it (and then moved to KiCAD because it's more powerful)
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Jul 26, 2017 14:32
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Meh, it's just whenever I want to edit fields in Eeschema, 95% of the times, the Clarify Selection context menu is pestering me, more so not doing anything when I pick an option. And when dragging selections around, say to rearrange things, the wires just detach instead of extending/rerouting. I mean, I'm new to this, but it's counter-intuitive as hell.
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Jul 26, 2017 14:34
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Combat Pretzel posted:Meh, it's just whenever I want to edit fields in Eeschema, 95% of the times, the Clarify Selection context menu is pestering me, more so not doing anything when I pick an option. And when dragging selections around, say to rearrange things, the wires just detach instead of extending/rerouting. I mean, I'm new to this, but it's counter-intuitive as hell. Yeah the clarify selection thing is kinda annoying, though it only appears if you're over a bunch of stacked things so if you zoom in a bit it happens less and once you learn its names for everything it's a bit easier to not pick the one that does nothing (ugh). There might be a mode to have it automatically reroute when you drag things but I've just sorta gotten used to it I guess  Both of those things are indeed things that other tools do different/better though so if that's what's bothering you yeah look around some.
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Jul 26, 2017 14:38
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Hey thread, sorry if this is in the wrong place, I already posted it in the vintage thread but I don't think that's the right place either. I've got a couple pairs of B&O speakers that I need to repair. One of my s80.2 has a pretty bad cabinet ringing/rattle that I suspect is from the PO replacing one of the drivers. The other is an MC 120.2 that has some weird distortion at a very specific frequency: unfortunately that freq is the same as my Samsung TV's menu sounds, so it drives me absolutely nuts every time I go to change inputs or bring up the menu. I can't really find any good resources for restoration of either of these speakers. I've checked the Beoworld forums but there's not much specific to either of these speakers in that regard. Right now the plan is to replace the woofers in both the s80.2 with matching woofers. There's some random PartsExpress woofer in one cabinet and an original woofer in the other. Both work, but there's sonic differences between them that bother me. This is not the cause of the distortion, but is a "while you're in there" repair. Is there a resource that can help me figure out an appropriate woofer to use to replace them with? Also, what gasket material or glue should be used in the cabinet repair? I suspect that the MDF is probably fine, but the front won't seal well. I can feel air blowing out the bottom of where the face meets the cabinet. I'm going to rebuild the crossovers and rewire the cabinet. What electronic component suppliers do you guys recommend? (this one might be a question for the Electronics Megathread) As for the MC 120.2's, I don't even know where to begin diagnosing this. I'm thinking start by rebuilding the crossovers and such and see if that shores it up?
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Jul 26, 2017 20:59
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Combat Pretzel posted:Are all electronic CAD applications as cumbersome to use as KiCAD? CircuitMaker is good and intuitive as far as they go. I have heard bad things about KiCAD's learning curve
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Jul 27, 2017 00:46
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Picked up this Kester 63/37 leaded solder from Amazon: https://smile.amazon.com/Kester-24-6337-0027-Solder-Alloy-Diameter/dp/B0149K4JTY It's like a whole new world now. My TS100 iron can melt the solder as low as 190c, and at 190-210c it makes hardly any flux fumes.
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Jul 27, 2017 01:59
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When I design a 4 layer PCB, and make the inner two layers the power and GND layers, I just create vias accordingly and then fill the layer? Maybe create some voltage domains? I'm not going to draw thick traces or something, right?
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Jul 27, 2017 02:14
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Zero VGS posted:Picked up this Kester 63/37 leaded solder from Amazon: https://smile.amazon.com/Kester-24-6337-0027-Solder-Alloy-Diameter/dp/B0149K4JTY Im not fantastic with electronics but leaded solder reminds me of being 12 and learning at school. It also reminds me how much easier to work with the drat stuff is.
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Jul 27, 2017 02:29
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ate all the Oreos posted:KiCAD is one of the easiest ones I've used so... yes. The real fancy paid pro poo poo like Altium has a better workflow in my opinion but also several orders of magnitude more complexity and things to tweak and fiddle with Altium is one of the hardest programs I've ever had to learn, but mostly because it doesn't use many of the common software conventions (for example, you press ctrl+c to copy, and yes, this is the correct shortcut, however it will now expect you to click a point that will be the "origin" of the thing you're copying. If you don't notice this and click somewhere, you won't copy. Another example is that you press 'w' in schematic to draw a wire, and 't' in the PCB design to draw a track. Considering that tracks and wires are effectively exactly the same thing, and that it's impossible to draw a wire in PCB mode or a track in schematic mode, there is literally no reason they shouldn't share a hotkey. The whole program is like this, it took me a few weeks to be able to use it and about 6 months to work out the best workflow (mainly because you don't realise your workflow isn't good until you come back 3 months later to make changes). There's about a million ways to do your component library for a project and all of them are wrong. And Altium is meant to be one of the best and easiest so, uhh, yeah they're all awful.
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Jul 27, 2017 05:24
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Combat Pretzel posted:When I design a 4 layer PCB, and make the inner two layers the power and GND layers, I just create vias accordingly and then fill the layer? Maybe create some voltage domains? I'm not going to draw thick traces or something, right? You got it. In higher layer count (6 and up), you'd also be using those ground planes to shield high speed signals in the inner layers, so you could actually pass EM emissions testing
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Jul 27, 2017 07:36
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Splode posted:There's about a million ways to do your component library for a project and all of them are wrong. Totally agree. I learned EAGLE first and then starting working for a company that used Altium. To get up to speed quickly I went to a 40 hour Altium training course. Everyone at the course agreed that they only found about 8 hours of content actually useful, but that 8 hours was different for everybody. To really get the most out of Altium you need to learn to do things the Altium way.
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Jul 27, 2017 19:28
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Used my multi meter to test the current draw of the motor under load, the datasheet im going off says it should pull about 310ma to supply 0.3kg/cm of torque. Current draw under the load I tested with (should be close to the load while moving i hope) was around 150ma which means the torque required must be under the 0.3kg/cm number. That means that the 0.1kg/cm motor is probably my best bet, if 0.1kg/cm is not enough to move it then I can gear it to give 0.2kg/cm and that should hopefully manage it. I never realized how much of a pain this would be. Edit I just thought of. I have used some solderless hammer on headers for the pi zero and such, they are basically the best thing. Fit it, smack it with a hammer a few times. Secure connection with no soldering required. I can solder but the 40 pins on the pi zero were a bit daunting considering how out of practice I am. Edit the second. So I picked a spare motor out of my small spares pile, its a micro metal gearmotor that I had tried to test before but found it broken. With a little bit of fiddling I discovered that one of the axles (spindles?) the gears ride on was slipping out of its hole allowing the gearing to slip, using a pair of pliers and a little brute force and ignorance I managed to slightly bend the plate at the end of the gearbox to trap the axle properly. Shoved 5v through it and found it had a ton of torque and span very slow. Used a sharpie to mark the shaft (heh) I timed it at about 30rpm. This being half the speed of the motors i was looking at but roughly the same type Im going to assume it has twice the torque. This means I can bodge up an attachment to my rover and do some testing. The half speed will give me an idea of how fast the other motors will move the rover and if a single motor with double the torque can move the drat thing then I know that two motors with half the torque will do the job. Means I can order without worrying If i just spent money on useless motors. A very lucky find. Sorry if this is really boring to everyone. Kea fucked around with this message at 00:42 on Jul 28, 2017 |
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Jul 27, 2017 20:22
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I sent my friend a copy of your questions/comments and here's a fat text dump he sent me back: ---------- The Twin Avalanche is a replacement for my ordinary dice when I play D&D. It is not meant to be some crypto secure thing. If it was, it would be in a metal box with a single optical output and not in an acrylic box that bluetoothed to my phone. Please also note that I am not a trained electronic engineer, I am a software guy, and I will not be offended if you correct anything here and I all welcome suggestions. The primary source of randomness, as you guys have guessed, comes from reverse biasing a 2N3904 transistor. Most HRNGs then compare the output of the transistor to a constant voltage to get the 1 or 0 bits, or they put a capacitor on the output to keep an average and compare against that. The idea is that you want to have your comparison point voltage half way between the min and max voltage of the output from the transistor so that your 1s and 0s are balanced. You do this for efficiency more than balance as the bit stream at this stage will likely not be random for many reasons but the main one is simply the components all the way to where you actually read the 1s and 0s are not perfect and suffer from (not sure about the right word here but) cooldowns. Back about 4 years ago (?) when I first had the idea to make it, I didn't realise how important it was to get the power supply right. I read a lot about batteries and how their voltage changed as they discharged. If you are reverse biasing a transistor it is important to know that you have to have enough voltage on the wrong side to make it avalanche and produce random output. If that voltage drops below a certain (highish) amount, the randomness stops dead. It is also important to keep that mid point voltage comparison between the high and low transistor output. If the battery voltage sags and moves the high and low down and you keep the mid point constant, you say that bad four letter word that no random number guy wants to hear: bias. So I thought if I had 2 transistors, I could compare the output of both with an op amp comparitor. That way it didn't matter what the voltage did as the battery discharged, they would remain in the same range and the comparison would be 50/50 between them. Of course, many of you would know that this is no magic answer either. The transistors are never identical and the op amp has a maximum bandwidth that effectively limits the rate that you can read the HRNG. So I bought a bag of transistors and checked them on the scope and got a fast op amp. You have to remember, I want this for a rolling dice replacement, I am not streaming crypto here. That said I can't tell from my antique 10MHz scope what the rate might be. Big enough. Somewhere during the development, there seemed to be an explosion in cheap, small, up-down voltage regulators that kept the voltage almost rock solid until the battery was almost dead. That made my life a whole lot easier. Now I didn't have to worry about battery output voltage and I guess the whole idea of having 2 transistors could be thrown out. But I just liked it and it was working in my breadboard. The second source of randomness is the camera (black circle on the top of it is the lens cap) which will eventually point into a 'snow globe' that will sit on top. This is a replacement for actual dice, so the idea is that you pick it up and shake it to make a roll. The unit has ball switches in it to wake it up when you shake it as well. The camera streams jpg to the Teensy microprocessor where it will be whitened (software de-biasing) and merged with the random stream. It is meant to be the obvious or decorative source of randomness that others can see and appreciate, whereas the real hard work is coming from the transistors. It is important that others at the table can have a sense of trust in your rolls and not just have a magic black box. There are a lot more details for this project that I will probably put online one day. There could be a whole chapter on: finding the right sparkles for the snow globe, whitening hardware RNG bit streams, writing a small whitening language to test whitening algorithms, testing for randomness (with testu01), development of the dice rolling language (eg 3d6+4), development of a compiler compiler to write the dice language with, making your cheap Chinese CNC mill work accurately (with a Teensy and some piano board found during kerbside rubbish collection), writing your own gcode library with awk, designing your own gcode font, hardware RNG that passes testu01 from your PC's clock. It is all for fun. If I did it all again, there would just be 1 transistor and I could get a smaller camera too. One day! Here is the schematic so you can see my cargo cult electronic engineering skills. 
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Jul 28, 2017 05:25
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Kea posted:Motor stuff Not at all, and this is the sort of stuff that is hardest to learn. Engineering courses show you the formulas involved, and you realise you're never going to know enough about the finished product for them to be useful, and most online advice for this sort of things starts assuming you have already found appropriate motors. Keep posting updates, and throw some pictures in towards the end. -- Gromit posted:Magic random box Geez this guy claims not to be an electronics engineer but he knows more about it than most mechatronic engineering graduates I know. -- I have just finished my personal project. I wanted a way of turning my heater on in the mornings remotely, so that I didn't have to get out of bed to warm the room up (because then I'd be cold). I also wanted my heater to turn itself off at night after I'd gone to sleep, so I didn't accidentally leave it on all night. Because I could I figured I'd also add thermostat style temperature control, as the heater itself doesn't have one. My first prototype used an Arduino Uno and a relay (interrupting the active on an extension cable) to control the heater. There was a hard coded time zone in the evenings when it would turn itself on, and a switch to override the time period and turn the heater on immediately (the override reset itself at midnight). To track the current time, rather than using a dedicated RTC, I just used the Uno's crystal. It wasn't super accurate but losing a few minutes a day didn't matter. The problem was that I had to manually set the time every time it lost power, over serial. I set the target temperature this way too. This sucked, as programming the thing with a laptop was more inconvenient than just operating the heater manually, so that winter it just didn't get used. As a stop-gap measure, I added a bluetooth module I had kicking around from a university project. This let me talk to it using a bluetooth serial terminal app on my phone, and that was good enough that I've been using it all winter. But, after hearing about ESP8266s I knew I could make a way cooler version of the same device. The new device uses an ESP8266, which lets me control the device via a webpage on my local network. Now, I can control and monitor the heater from any phone or computer without needing an app, and from multiple devices at the same time.  It also means that instead of doing the time tracking myself, the ESP8266 can just go and get internet time. This means no more reprogramming the time in the event of a power loss. (ti also means if my router goes down my heater will think time has stopped, but welcome to the Internet Of poo poo).   A pushbutton with an inbuilt LED lets me toggle the timer override, and the LED indicates whether it's activated or not (this was a problem in the original prototype, as the timer override could be toggled by either software or hardware, the physical position of the switch didn't give you any indication of whether the timer was overriden or not.) I replaced the temp sensor with a better one I had lying around from a different uni project, 3D printed a custom case, and bob's your uncle, fanny's your aunt, I never have to get out of bed again. The thing is basically a fancy remote controlled extension cord. I carefully removed some of the insulation on an extension cord, and only severed the active line. This was soldered to the terminals of the relay board, as I do not trust those lovely screw terminals at all, especially when it's 2400W through multicore cable. Huge shoutout to the 3D printing thread who helped me beat my uncooperative bargain bin 3D printer into working long enough to finish the long, long print. Splode fucked around with this message at 07:40 on Jul 28, 2017 |
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Jul 28, 2017 06:55
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Imo if I was ever going to send mains through a PCB id use surface mount wago connectors
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Jul 28, 2017 09:42
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Malcolm XML posted:Imo if I was ever going to send mains through a PCB id use surface mount wago connectors Yeah I'm not completely happy with the mains stuff, but the module doing it currently claims it can handle it. The internal temperature sensor is reporting a temperature a few degrees higher than the rest of the room, but nothing alarming, and that's probably just from the relay coil being energised for long periods. edit: just did a little more research and it seems like, electrically, the mains connections it should be fine. I am not worried about the physical connection as strain relief is provided by the design of the enclosure. Splode fucked around with this message at 13:31 on Jul 28, 2017 |
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Jul 28, 2017 12:59
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About reflowing, poo poo's too crowded on the board I'm trying to route, but I have plenty of caps top-side that are annoying. Is the surface tension of solder high enough to keep 0603 parts from falling off a bottom side after they've been soldered?
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Jul 29, 2017 20:00
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Splode posted:Yeah I'm not completely happy with the mains stuff, but the module doing it currently claims it can handle it. In my experience using a DHT11/22 sensor with an ESP board without an enclosure, there was also an elevated temp reading relative to the room. It turns out the ESP chip itself was the source of the extra heat and moving the sensor about 30cm away gave more accurate readings
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Jul 29, 2017 22:24
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I've got a thing that's running with relays and physical switches that I want to control remotely. The switches are 120V, switching 120V relays to control 240V power to a number of things. This part is working wonderfully, and I'd like to just replace the switches with something I can control with logic, preferably 3.3V. There are 8 switches right now, and I'd like to keep the whole project under $40 and I still have to get the controller, but that's going to be some flavor of ESP module. What's the current go-to for switching a 120V low-amp load for less than $2/module? edit: The relays pull 30-190mA each, switching ~50A 240VAC. babyeatingpsychopath fucked around with this message at 23:21 on Jul 29, 2017 |
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Jul 29, 2017 23:04
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ickna posted:In my experience using a DHT11/22 sensor with an ESP board without an enclosure, there was also an elevated temp reading relative to the room. It turns out the ESP chip itself was the source of the extra heat and moving the sensor about 30cm away gave more accurate readings Oh right of course, thanks. babyeatingpsychopath posted:I've got a thing that's running with relays and physical switches that I want to control remotely. The switches are 120V, switching 120V relays to control 240V power to a number of things. This part is working wonderfully, and I'd like to just replace the switches with something I can control with logic, preferably 3.3V. I'm not sure I am following, are you using relays that have a 120V input voltage? The only way to switch that is going to be another relay. Assuming I've misunderstood, To switch a relay with a microcontroller you need a mosfet. Mosfets cost cents. In the event you need to switch a huge load you can use a small mosfet to switch a bigger one too. If those existing relays really do require 120V input, you'll need to buy some 3.3V or 5V (input voltage) relays rated to least 120V and energise them with an n channel mosfet. Most circuits I see for this purpose also have a diode. If you google mosfet relay circuit on Google Images you will see what you need.
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Jul 30, 2017 00:52
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