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I guess it's time for me to send my order to PCBway then - wish me luck!
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Jan 29, 2024 03:59
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babyeatingpsychopath posted:Which ancient-rear end dry contact garage door opener do you have? I would presume the ratgdo would play well with the switches as they sit, since that's what it was designed for: to be a drop-in thingy for old-rear end openers. I think it was designed to be a drop-in for Security+ 1.0 and 2.0 new openers, and older ones are an afterthought. I don't think I can transfer the existing limit switches to the ratgdo directly because then how will the opener know when to stop?
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Jan 29, 2024 17:28
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Skinnymansbeerbelly posted:I think it was designed to be a drop-in for Security+ 1.0 and 2.0 new openers, and older ones are an afterthought. I don't think I can transfer the existing limit switches to the ratgdo directly because then how will the opener know when to stop? I was under the impression that the switch inputs are paralleled in. The opener sees what it needs to, and the wifi control board sees the same thing, so it knows the status of a dumb opener.
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Jan 29, 2024 17:51
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Yeah, if you have an old opener, just get an OpenGarage. It just has a relay right on the signal wire, you only need the ratgdo for Security+ stuff as it knows how to talk the encrypted protocol. The OpenGarage device gets the state of the door using an ultrasonic sensor (so you can get creative with *where* you mount it if you have some special requirements, it also has the option of being pointed at a car so it can tell you if the car is present or not). I have an OpenGarage wired to a Security+2 switch (they sell them pre-modded, but the output from the OG is just wired straight to the microswitch inside the button so the microcontroller thinks it's pressed manually and sends the encrypted message), but I intend to upgrade to ratgdo, but I'm going to DIY it since I want PoE and not wifi. I already got a PoE ESP32 board, just need to get around to tweaking the ratgdo firmware to talk to the right pins (its default pins are shared by the PHY) and DIY the interface circuit. I've actually heard of some people having trouble using the ratgdo on "old" openers, apparently it had some noise/glitch/something on its outputs that didn't matter for Security+ as they wouldn't have been understood as packets, but it triggered the old openers, people would find their door randomly open at night and things. I think it's been fixed but something to be wary of.
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Jan 29, 2024 22:18
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Why use something off the shelf when I can make something super jank instead? I think I'm going to ESPhome it as there are other environmental sensors I want to throw on. Are there any pitfalls I should be aware of using an LTC4311 to extend the i2c bus a couple yards out?
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Jan 29, 2024 23:14
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Skinnymansbeerbelly posted:Why use something off the shelf when I can make something super jank instead? I think I'm going to ESPhome it as there are other environmental sensors I want to throw on. Are there any pitfalls I should be aware of using an LTC4311 to extend the i2c bus a couple yards out? I2C* was designed to never leave a circuit board, so there are a lot of pitfalls, but if you stay within what that LTC chip says it can do you'll probably get away with it. Just make sure your software can handle the occasional bit of messed up i2c traffic. I^2C, Is IIC for inter-IC - it's specifically designed for communication between two ICs on the same pcb. It doesn't have any of the features that communication protocols designed for inter-device protocols have. RS485, CAN, USB, ethernet, RS232 are all more reliable options but obviously will complicate your design.
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Jan 30, 2024 13:21
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Skinnymansbeerbelly posted:Why use something off the shelf when I can make something super jank instead? I think I'm going to ESPhome it as there are other environmental sensors I want to throw on. Are there any pitfalls I should be aware of using an LTC4311 to extend the i2c bus a couple yards out? If you're aiming for super jank, I2C is probably just fine. I run an I2C particle sensor at the end of a 7 meter length of repurposed USB cable with the ends cut off, at the slow 100kHz rate on an Arduino and don't have any noticeable problems with lost data. I use 4.7k or 2.2k pull up resistors and no special LTC4311-type devices.
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Jan 31, 2024 05:37
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Skinnymansbeerbelly posted:Are there any pitfalls I should be aware of using an LTC4311 to extend the i2c bus a couple yards out? BOM cost. (I say this as someone who uses a lot of Linear chips in my hobby projects.)
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Feb 2, 2024 09:03
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You’ll have edge rate issues at that length but if you operate slowly it might be okay. That bus length will carry significant RLC which fucks with I2Cs open drain
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Feb 2, 2024 17:20
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PRADA SLUT posted:You’ll have edge rate issues at that length but if you operate slowly it might be okay. That bus length will carry significant RLC which fucks with I2Cs open drain If you want the complete overkill solution to the electrical problems of taking I2C off-board, you can get a pair of LT3960s (edit: oops, not the 3690). These tunnel I2C through the CANbus physical layer, complete with matched termination and differential signaling. Stack Machine fucked around with this message at 15:39 on Feb 4, 2024 |
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Feb 2, 2024 18:16
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Here’s an idea: I2C into a buffer, output two signals, invert one of them, send it along a 100Ohm line, and then subtract at the end. Fake-rear end I2C CI DP
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Feb 2, 2024 23:48
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I think you mean LT3960 not 3690. Thanks for this tip it could solve some problems for me as well. At my work we misuse I2C over long distances all the time and the only time we run into trouble is when the com references signals get to far apart which happens from time to time when line losses and irresponsible loads on low voltages pull the common signal up. Running the wires in the same cable as switched power will definitely break it too. In a specific case i ran it down 50 feet of low capacitance wire with no trouble. Although I now wish I had used USB, would have saved some money.
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Feb 4, 2024 00:24
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Giganticon posted:I think you mean LT3960 not 3690. Thanks for this tip it could solve some problems for me as well. At my work we misuse I2C over long distances all the time and the only time we run into trouble is when the com references signals get to far apart which happens from time to time when line losses and irresponsible loads on low voltages pull the common signal up. Running the wires in the same cable as switched power will definitely break it too. In a specific case i ran it down 50 feet of low capacitance wire with no trouble. Although I now wish I had used USB, would have saved some money. Yes, I meant the LT3960 "I2CAN" controller. It also has a super-wide supply range so you don't need to bring a special power supply. I think it's best for slapping onto boards with I2C/PMBUS/whatever switching regulators and not many other components in inconvenient places. Stack Machine fucked around with this message at 18:00 on Feb 4, 2024 |
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Feb 4, 2024 16:06
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Any goon recommendations for a good mid-level bench adjustable DC power supply? I'd say 30V, 10-15A max.
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Feb 6, 2024 02:34
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AlternateNu posted:Any goon recommendations for a good mid-level bench adjustable DC power supply? I'd say 30V, 10-15A max. https://www.ebay.com/itm/256397542380 I’m not necessarily recommending this particular supply (esp because I’m phone posting). But old HP stuff was hot poo poo back in the day, and it’s not like volts and amps have changed since then. Very heavy though. e: search for the model number on EEVBLOG and similar forums in case there are any gotchas. Lots of calibration sticker residue likely means it spent its life in a climate controlled commercial or govt lab, with yearly calibration. ryanrs fucked around with this message at 04:20 on Feb 6, 2024 |
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Feb 6, 2024 04:10
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AlternateNu posted:Any goon recommendations for a good mid-level bench adjustable DC power supply? I'd say 30V, 10-15A max. I own not one but two of these: https://www.amazon.com/gp/product/B08DJ1LP2Y/ Because I liked the first one enough for charging large lithium batteries (multi KWH) that I got another so I could charge two at once. It will put out the full 300 watts for days on end if needed. It is a little weird how you set the amps, you have to short the cables together and turn some dials, then you unhook them and adjust the voltage. In any case it works and they're $58 each. The Amazon listing shows a cutaway to the componentry used inside. Maybe it's garbage for all I know and isn't precise enough for some uses, but it has been lining up with my multimeter each time. Most of the other reviews are pleased.
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Feb 6, 2024 04:27
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2.75 lbs, drat. Gonna remember that every time I have to move my stupid 35 lbs boat anchors.
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Feb 6, 2024 04:46
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ryanrs posted:2.75 lbs, drat. I'm sure it could be lighter if the case was aluminum or plastic but they went with steel for most of it. Those rackmount HP supplies I'm assuming most of the weight is big iron transformers like in the old wall-warts?
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Feb 6, 2024 05:14
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The HP’s GPIB cables weigh more than 2.75 lbs.
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Feb 6, 2024 05:19
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I've worked with a lot of old HP test gear and despite the age they're generally great at what they do. It's amazing how fall they've fallen - there was a time when getting an HP product meant that you were getting a top tier piece of equipment that was designed to last forever. Hewlett and Packard must be spinning in their graves over what their brand means now. GPIB is frickin' nuts by the standards of modern design. It's like 16 interlinked hardware finite state machines that somehow combine into a Voltron of a working protocol. e: The old HP3458A 8.5 digit meters are a fun bit of engineering to dive into. The analog board was not supposed to be touched without gloved hands so your skin oils wouldn't contaminate the surface and throw off the readings. There are some cut-outs on the board designed to minimize stress or thermal connections that would induce on-board voltage offsets. The sample-and-hold capacitor for the ADC is a winding of teflon core coax cable that is rolled into a reel since that was the only way they could get a low enough capacitor leakage. e2: You can see the rolled-up teflon coax cap in the lower left: 
PDP-1 fucked around with this message at 06:03 on Feb 6, 2024 |
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Feb 6, 2024 05:45
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The 3458a is still pretty pricey, but the 3457a is $300-500.
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Feb 6, 2024 06:07
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AlternateNu posted:Any goon recommendations for a good mid-level bench adjustable DC power supply? I'd say 30V, 10-15A max. I've used a couple Korad KWR103 for a few years, and they've performed quite well. Here's the one youtube review I've found for it: https://youtu.be/FW4PiFHLIHw?si=7KJY5dqX4VJQlJlM 60$ for that Kungber tho  . I doubt it can actually hold up to its specs but even if it can only do 5A that's a good deal.
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Feb 6, 2024 19:13
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PDP-1 posted:I've worked with a lot of old HP test gear and despite the age they're generally great at what they do. That reminds me, I was browsing ebay looking for deals on test equipment and there's hardly any point to looking at boat anchors anymore. New equipment from Siglent/Rigol/etc seem to always offer a better value for most types of equipment (scopes, DMMs, PSUs, etc), unless you get very lucky. Or you need a literal boat anchor.
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Feb 6, 2024 19:25
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ryanrs posted:But old HP stuff was hot poo poo back in the day This is the truth. HP test equipment was the top of the line for decades, up there with Techtronix for scopes. Like Techtronix, expect great documentation too. They changed their name more recently though. Or got bought out. I want to say Agilent? ryanrs posted:Lots of calibration sticker residue likely means it spent its life in a climate controlled commercial or govt lab, with yearly calibration. Also the truth. My VTVM still has its badge from the University of Oregon and I've never been to the west coast. Edit: v v v thanks kid sinister fucked around with this message at 21:13 on Feb 6, 2024 |
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Feb 6, 2024 21:08
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Agilent then Keysight.
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Feb 6, 2024 21:10
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Should we hold a contest and see who has the oldest test equipment? I might win though. I got stuff from the 50s.
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Feb 6, 2024 21:18
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I have no idea why HP/Agilent/Keysight bothered with their rebrandings. I guess the first one was a spinoff, but it was very low effort, as the primary scope I still use (two oscilloscope and sixteen logic analyser inputs) is the Agilent 54622d and every accessory it had was HP-branded, only the machine itself says Agilent. I also have an HP 16500B that came out in something like 1992 that I use when I have lots of logic I need to analyse (it has 96 inputs or something with the cards I have in it). It also has a two channel scope with a comically low framerate. When I first picked it up it still had the configuration loaded from whatever company owned it in 1999, who had been using it to debug a 486. Best bit about HP/Agilent is their site still has all their old stuff. They just posted all the tools and option software packages for free once they decided the unit was obsolete.
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Feb 6, 2024 21:37
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I love 80s vintage HP gear. The boards look amazing. All the traces were gold plated before the (clear) solder mask was applied. I can't think of any reason you'd want to waste all that gold, but it looks great. Edit: I guess this is the best photo I have of one of these boards, but just look at this thing. Those aren't bare traces: 
Stack Machine fucked around with this message at 21:58 on Feb 6, 2024 |
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Feb 6, 2024 21:41
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Feb 6, 2024 22:04
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Charles Ford posted:I have no idea why HP/Agilent/Keysight bothered with their rebrandings. I guess the first one was a spinoff, but it was very low effort, as the primary scope I still use (two oscilloscope and sixteen logic analyser inputs) is the Agilent 54622d and every accessory it had was HP-branded, only the machine itself says Agilent. The lab test business unit just got spun off the parent company twice with the parent keeping their other areas. (for your scope accessories, if they were manufactured after the split, there was probably a licensing agreement to let Agilent use the HP trademarks for some period of time)
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Feb 6, 2024 23:14
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Stack Machine posted:I love 80s vintage HP gear. The boards look amazing. All the traces were gold plated before the (clear) solder mask was applied. I can't think of any reason you'd want to waste all that gold, but it looks great. That's gnarly looking.  Thanks for the recs folks. I like the form factor of the Kungber. (I don't have a whole lot of desk space.) But no OC protection is kind of a dealbreaker. (Also, the knobs having maxs/mins is annoying.)
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Feb 6, 2024 23:20
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ANIME AKBAR posted:That reminds me, I was browsing ebay looking for deals on test equipment and there's hardly any point to looking at boat anchors anymore. New equipment from Siglent/Rigol/etc seem to always offer a better value for most types of equipment (scopes, DMMs, PSUs, etc), unless you get very lucky. Or you need a literal boat anchor. Totally agree. I work at a university physics lab that was founded in the 90s so we have a lot of the older boat anchor type stuff that is still around and kicking. But 90% of grad student experiments don't need anything like that kind of precision/stability so I've been advocating with some success to buy a boatload of Rigol/Siglent/etc type stuff for basic use and reserve the really high end stuff for when it's actually needed. We lost a really nice Tektronix scope a couple of years ago when a student hooked it up to mains voltages with the shield and sense lines reversed. Everyone makes a few dumbass mistakes like that when they're learning but it hurts a lot less if the scope is a $300 Rigol vs a Tek scope that costs more than most cars. Also pretty much all of the new stuff works on Ethernet/USB which makes it a lot easier to throw together a system that doesn't have any hard data latency requirements for cheap. The old stuff is all GPIB and GPIB-to-USB dongles are stupid expensive, not to mention the cables.
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Feb 7, 2024 05:30
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Back to amateur level. Adding an aux-port for my old car stereo. I disconnected the left and right channels between the radio tuner and the amplifier and replaced them with two pairs of wires. I'll add a switching 3.5mm audio jack so that it gets the radio signal when unplugged and when plugged in it gets whatever I plugged in (basically my phone then). I guess I could have just gotten one of those cassette adapters which are actually very good. But I wanted it to be sleeker, more factory looking and not have a wire hanging out of my stereo. Gotta say I think this old stereo is way nicer than any modern infotainment system, actual drat buttons to start. God I hate that crap in cars, just get rid of it, it's just something to break and get ugly and obsolete looking and just prematurely make the car feel dated. I'd rather use my phone which gets upgraded semi-regularly.
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Feb 7, 2024 07:40
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Also, does anyone know if there exists snips like these, but the cutting part is like 2 times longer and preferrably even flatter, to really get into tight spaces.
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Feb 7, 2024 08:09
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Over 1,000 variations of cutters: https://www.techni-tool.com/category/Hand-And-Power-Tools/Hand-Tools/Cutters/Cutters
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Feb 7, 2024 08:29
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Speaking of electronics tools. I wish I had something like tweezers but would be easier to both position AND apply downforce at the same time. I have lots of good tweezers but when soldering very small resistors/capacitors, I usually run into the problem that: A) When gripping the part by the sides, its hard to apply downforce to make sure the component is flat against the PCB when there's existing solder on the pad and I'm trying to tack it into position. B) If the part isn't flat, trying to push on the top of the part with the tweezers usually results in it sliding around to the side once it reflows, so it's now flat but no longer centered. Some kind of tweezers that have a little ledge/step on the inner side to grab the top corners so I can position and hold down at the same time? Hard to explain what I'm picturing I guess. Maybe there's a more obvious solution.
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Feb 7, 2024 15:23
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Rescue Toaster posted:Speaking of electronics tools. I wish I had something like tweezers but would be easier to both position AND apply downforce at the same time. I have lots of good tweezers but when soldering very small resistors/capacitors, I usually run into the problem that: Not really what you're describing but I had all sorts of problems with tweezers and tiny parts until I got these: https://www.amazon.com/gp/product/B078CR1HVF/ They're titanium so completely nonmagnetic, are made well and come to very fine points so you can apply force to very precise, small areas, and they have this little peg in the handle bit that engages a hole in the other handle bit and ensures that when you squeeze them together they come together perfectly aligned. As a result you can grip tiny things with a lot more force than you can with other tweezers, since there's way less misalignment to cause the thing you're gripping to twist and ping off somewhere, and I've been able to do stuff like you're describing (grab a thing and push it down at the same time) with far less trouble than other tweezers give me. The only thing is you gotta be careful not to bang the tips on stuff, they're strong enough that they won't bend under normal use but if you donk them into your table hard enough they sure will. They come with this plastic box thing that keeps them sorta hovering in mid-air in the middle of the box so they won't get damaged and I make sure to always put em' back in there when I'm done using them.
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Feb 7, 2024 15:39
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The solution is to clean the pads first and just add fresh solder while being able to keep it flat and centered. I dunno. I’m not even close to the most experienced person in the thread, but I’d say you really shouldn’t be putting downward pressure on components that small anyway. Just the weight of the tool should be enough to keep it in place while attempting to tack it with preexisting solder.
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Feb 7, 2024 15:39
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AlternateNu posted:The solution is to clean the pads first and just add fresh solder while being able to keep it flat and centered. Eh in my case sometimes I accidentally bump something while reflowing it, breaking out the solder wick and cleaning everything up is a bit much when you can just hold the thing there and re-melt the solder that's already on the part and the pads. And it's not like you're applying a ton of force or anything, just enough that it doesn't slide around while everything melts back into place.
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Feb 7, 2024 15:45
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Rescue Toaster posted:Some kind of tweezers that have a little ledge/step on the inner side to grab the top corners so I can position and hold down at the same time? Hard to explain what I'm picturing I guess. Maybe there's a more obvious solution. I had some that sound like you describe, but I lost them. They were part of a set of plastic tweezers for dipping semiconductors and boards into acid in a wet-chem lab. Doubt they be useful for your purposes though.
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