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24v DC, not AC, right?
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Dec 30, 2023 00:00
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ante posted:24v DC, not AC, right? Oh yeah good point, if it's buzzing that sounds like you're feeding it AC when it wants DC. e: Well the product page they linked that I didn't initially see says: 24 VAC 50/60Hz (cycles per second) solenoid power requirement: 0.450A inrush current, 0.25A holding current So  e2: I also saw the 47 ohm measurement mentioned but missed the part where they said the manufacturer specifies it should be 38 ohms, I've never seen a solenoid where the resistance is off by over 20% like that, that'd be like "accidentally" winding an extra few hundred turns of wire... Shame Boy fucked around with this message at 00:12 on Dec 30, 2023 |
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Dec 30, 2023 00:07
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The power supplies for those irrigation controllers are like 20VA max. That said, the inrush is completely unreal. They're specced at less than an amp, but I've seen 5A inrush in the field. I suspect your power supply is browning out at the inrush. edit: Shame Boy posted:Oh yeah good point, if it's buzzing that sounds like you're feeding it AC when it wants DC. 20% is well within tolerance for consumer-grade garbage that's typically overdriven.One thing to note is that these irrigation valves are pilot valves. They rely on the main water pressure going up into the valve/solenoid body to reliably actuate. The solenoid itself moves a TINY bit, which opens a TINY passage which lets full water pressure into the diaphragm to open the valve fully. The buzzing may just be it floating around in its housing because there's no pressure pushing it towards one stop: power goes on and it shoots to one end of travel, hits the rubberized stop, bounces, repeat.
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Dec 30, 2023 00:33
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ante posted:24v DC, not AC, right? That was my thought too, although 24VAC is common for several household uses, like your doorbell and HVAC signalling.
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Dec 30, 2023 00:43
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I can't look right now, but I bet I got a DC supply instead of AC since that is the kind of thing I'd do despite checking multiple times.
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Dec 30, 2023 00:46
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Rocko Bonaparte posted:I can't look right now, but I bet I got a DC supply instead of AC since that is the kind of thing I'd do despite checking multiple times. Shoulda just got the rainbird transformer that was one bin over.
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Dec 30, 2023 00:47
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I confirmed 24 VAC supply and 24 VAC solenoid. I guess I did have a moment to check.babyeatingpsychopath posted:Shoulda just got the rainbird transformer that was one bin over. The Christmas elves hosed with the inventory of all the Lowes and Home Depots here. I suppose since I wound up stopping at multiple places, I could have, but I was starting to rage when I couldn't find a 20A GFCI, a standard-sized decora cover, white spray primer, and white spray paint all in one store. So I had consigned that one to Amazon. The supply is 730mA and the starting current is something like 450mA so I should be able to clear it. Well, now we assume the supply I got isn't AliXpress butt stuff. Edit: I do think I botched the relays though. 24V DC. I think that matters with solid state ones.
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Dec 30, 2023 00:53
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Rocko Bonaparte posted:Edit: I do think I botched the relays though. 24V DC. I think that matters with solid state ones. Oh, yes, it super does  That'd explain the buzzing, the solid state relay is probably only turning on for half the sine wave so the solenoid is trying to open and then immediately loses current 60 times a second.
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Dec 30, 2023 01:14
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Noo I don't even have the relay involved yet. I just connected the solenoid to the 24VAC power supply to test if it opened or not. I was curious if somehow that in itself would be stupid with these.
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Dec 30, 2023 01:51
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Rocko Bonaparte posted:Noo I don't even have the relay involved yet. I just connected the solenoid to the 24VAC power supply to test if it opened or not. I was curious if somehow that in itself would be stupid with these. Assume it's working until you prove it's not. You don't know what it's supposed to do when it's not hooked up in the way it's intended to be hooked up.
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Dec 30, 2023 02:23
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I think babyeatingpsychopath's point about the water pressure is important. Install it onto a water line and then test it.
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Dec 30, 2023 02:34
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I haven't eaten a baby but I'll agree
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Dec 30, 2023 02:34
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babyeatingpsychopath posted:Assume it's working until you prove it's not. You don't know what it's supposed to do when it's not hooked up in the way it's intended to be hooked up. There's this amusing phenomenon on Amazon reviews of auto-darkening welding helmets where the customer will 'test' the auto-darkening feature by looking at the sun. Then when the LCD shade doesn't activate in the sun, they return the welding helmet and write a 1-star review. Like, the entire point is that the filter turns on while you are welding, but these people don't understand that.
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Dec 30, 2023 03:27
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amazon reviewers are uniquely stupid people. i remember one time looking at reviews of little fluid compasses to go on my car dashboard. this kind that's a spinning ball in liquid:  since you want to be able to read it on a dashboard in front of you, it's designed so that the number facing you -- the "bottom" of the ball -- is the direction you're facing. this means that the area marked "north" on the ball points towards the south. like fully half the people reviewing these compasses do not understand this and think they got a defective one. Sagebrush fucked around with this message at 04:55 on Dec 30, 2023 |
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Dec 30, 2023 04:52
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It isn't unusual for a functioning normally sprinkler valve to buzz a bit. And it's almost certainly piloted, so nothing will visibly move when you energize it while it's sitting on a bench
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Dec 30, 2023 05:14
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Sagebrush posted:like fully half the people reviewing these compasses do not understand this and think they got a defective one. That's probably just Amazon's commingled inventory system mixing up compasses for the northern and southern hemisphere. 50% chance you get one with the wrong polarity,
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Dec 30, 2023 05:44
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Got my "bus" servos, they might be a bit stiff when "off" for what I wanted (being able to push the blinds manually) but maybe I can just make the arms that control them comically long or something (obviously at the expense of torque and resolution). Or I can just use them for something else. Pretty easy to interface though! I feel bad about feeding 5V straight into the ESP32's RX pin but the CEO of Espressif said it was fine on Facebook which is apparently just as good as an accurate datasheet in this day and age.
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Jan 1, 2024 22:56
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ryanrs posted:Super Blinky I finally got around to assembling it.   Hard to describe the brightness, but imagine me taking this pic while cowering behind my phone to keep the light out of my eyes. It is stupidly bright. It is probably eye-safe, so long as you don't stare at it. This device is essentially an LED-based heater attached to a 75 C thermostat. To test the temperature control, I heated the aluminum plate up to 100 C with a hot air gun. After holding it at temp for 15 mins to cure some thermal epoxy, I applied power and let it cool down with natural convection. As the temp ramped down, the LEDs started turning on. 100 C LEDs completely off 80 C LEDs turn on, very low current, as bright as a normal bike taillight 75 C LEDs significantly brighter, but not close to room temp brightness. The circuit reached thermal equilibrium at 75 C. So it works pretty good. Not sure what I can use it for, though. e: Construction Notes The starboards were not difficult to solder. Hakko 888 with a medium chisel tip at 350 C. Just gotta hold the iron on it for 10 secs to get it nice and hot. I used silicone wire so I didn't have to worry about the insulation melting. (This was with the little starboards sitting on a piece of wood. God help you if they're already bolted to the heatsink.) I'm very happy with JLC's assembly. This project was designed to use only components from their catalog, but that catalog is a lot larger than it was years ago. They've added lots of chips. Their parametric search is still total dog poo poo, though. BOM spreadsheet Receipt, for those curious what this costs. Prices are for 5 boards.  $50 pcbs $25 assembly setup $56 components $28 loading reels in to pick-n-place (I think) $2 assembly (automated soldering) $17 extra QA photos (for my approval before they ship) $26 shipping ($9) some coupon = $195 to JLC for 5 assembled boards. LEDs, heatsink, polycarbonate, terminal block, temp sensor, kapton insulator, thermal epoxy, thermal paste, screws and spacers also cost a fair bit. But since I did the final assembly myself, I only bought enough of these parts for 1 unit. $60 LEDs $72 heatsink (threaded holes were a killer) $6 polycarbonate window $20 kapton insulator = $158 for the stuff I assembled myself So I guess this LED blinky costs something like $200. Seems high, but the LEDs themselves were 30% of the final cost, so that ratio seems fairly reasonable. Getting 17 tapped holes at $3/ea hurt. If I made more of these, I think I'd use self-tapping screws. I'd also drop the LTC4365, I guess. ryanrs fucked around with this message at 05:39 on Jan 3, 2024 |
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Jan 3, 2024 01:00
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I've been meaning to play with this, in order to solve the categories issue https://yaqwsx.github.io/jlcparts/#/
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Jan 3, 2024 02:18
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As I recall, it helps the categories, but ultimately, JLC does not have Digi-Key's army of staff cleaning up product data. OTOH I do like buying 5 chips and only paying the reel price. e: That was too generous to JLC. JLC probably just has a couple guys using scripts to bulk-import manufacturers' data (badly). And I'm sure the language difference doesn't help. ryanrs fucked around with this message at 04:20 on Jan 3, 2024 |
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Jan 3, 2024 03:32
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Oof, I did *not* realise the Pinecil ships from China, probably would have sprung for the "courier" or ordered from Amazon. Luckily the local tool library has some basic irons so I'll grab one next time I'm in, right now it's just wiring up an offcut from a 5v LED strip to a USB plug.
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Jan 4, 2024 05:14
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Meanwhile I just have my Hakko. Maybe I'm missing out by going cordless?
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Jan 4, 2024 05:39
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kid sinister posted:Meanwhile I just have my Hakko. Maybe I'm missing out by going cordless? The ones posted here aren't cordless, just don't have a base station. Controls are on the iron and it plugs into a wall wart or power bank. They're nice, but Hakko just works too. Except for that stupid "hold up to calibrate" thing. What a dumb decision that was.
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Jan 4, 2024 06:00
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I hadn't even considered tip availability for these portable irons. They're no Hakko or Weller. Do they have anywhere near the tips of those two? I like my tips.
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Jan 4, 2024 06:16
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Bondematt posted:
Worst. Interface. Ever.
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Jan 4, 2024 06:42
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I keep thinking I should build a hyperspectral LED array. It would be like an RGB LED but with more colors. So instead of selecting an [R, G, B] value, it's a 10-20 element vector. Some channels might be IR or UV. With a mix of standard and phosphor converted LEDs, you can even do wideband/narrowband color stuff. E.g. Lumileds Luxeon C.  On the sensor side, AMS has interesting spectral sensors like the 14-channel AS7343. Costs $10, which is pretty cheap. Spectral response:  This is not a fully baked idea. I'm not sure what it could be used for, or even if it'd be an interesting demo.
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Jan 4, 2024 08:24
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I built a demo PCB of the entire Luxeon line. It was fun, and helped with some colour science stuff I do for work. Colour sensors like that aren't really that useful even as a "hey cool, look at this" thing, unless you have a specific purpose in mind where you know you need certain wavelengths. With the time invested in trying to turn it into something useful, I'd rather spend money on either a tool like a Sekonic , or a very capable sensor module from Hamamatsu. They're both rad, using a linear CMOS sensors, and linear filter, or diffraction grating, respectively. I'm a little jaded though maybe, because I do have access to the cool tools.
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Jan 4, 2024 08:40
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A few weeks ago I spent a couple hours spec'ing out all the stuff needed to DIY my own spectrum analyzer from bits people are selling on ebay and then realized it was going to cost like $300 and I have no idea what I would use it for
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Jan 4, 2024 09:44
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Same thing you use an oscilloscope for, a physical visualiser for the music you're listening to.
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Jan 4, 2024 09:48
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Charles Ford posted:Same thing you use an oscilloscope for, a physical visualiser for the music you're listening to. I meant a light spectrum analyzer, as in a thing that analyzes the spectrum of light. Though I think the more specific name would be like spectroscopic analyzer? I know if you couple it with a calibrated light source it becomes a spectrophotometer and that was the ultimate goal so I guess call it that.
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Jan 4, 2024 09:55
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Oh, then yes, I’ve occasionally thought about buying one, but I don’t think I’d try and make even a toy one myself as I imagine I’d be disappointed with the results. But I have no real use to justify the expense.
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Jan 4, 2024 10:19
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kid sinister posted:I hadn't even considered tip availability for these portable irons. They're no Hakko or Weller. Do they have anywhere near the tips of those two? Yeah, they are interchangeable with the TS100 tips, which seem to come in a decent range.
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Jan 4, 2024 15:59
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If anyone's interested, while I was digging around on ebay I found this dude that basically sells everything you'd need to make your own spectrometer out of old used parts: https://www.ebay.com/sch/i.html?_ssn=spectrophoton&store_name=spectrophoton&_oac=1 Specifically I was thiiis close to dropping two hundred bucks on this thing, which seems like it wouldn't be all that hard to get working, before realizing I have absolutely no use for it: https://www.ebay.com/itm/143989529085 e: Also the word I couldn't remember last night and kept stumbling over was "optical spectrometer", for the record. Shame Boy fucked around with this message at 16:31 on Jan 4, 2024 |
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Jan 4, 2024 16:27
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Hi everyone, idiot here! I have a weird question regarding car electronics; I installed a backup camera in my truck that utilizes a 12V DC connection to the reverse light to power the camera, and when the head unit detects a signal, it interrupts whatever is on-screen to present the camera image. Now, joy of joys, I found that every time I hit the brake pedal in the truck, the head unit momentarily tries to display the reverse camera. This means every time I hit the brakes, the head unit cuts out and mutes the sound, thinking I'm backing up, then almost immediately goes back to normal operation while the brake stays depressed. I have two theories on this: 1) when pressing the brake pedal, the current spike from the brake lights turning on makes just enough EMI to momentarily excite the power cable leading to the camera, causing it to turn on. I think this is unlikely as the bulbs in the truck are incandescent and (I believe) a linear load with no real current spike, so I don't know how a pulse that powerful could be made unless the wiring in the truck is that noisy/crappy 2) the composite cable that runs from the camera feed to the head unit is getting interference from the power cable for an active trailer wire controller sitting next to it. Every time I hit the brake the resulting EMI pulse gives just enough voltage/current to confuse the head unit into thinking that the camera's turned on. However, the RCA composite video cable is supposed to be shielded, so I thought it was somewhat immune to this. Below is my hacked-together, completely-unprofessional circuit diagram that oversimplifies everything because I'm an idiot, remember?  Anyone have any advice on any DC filtering I could do? Would a simple capacitor and diode between the camera's power and wiring harness potentially help?
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Jan 4, 2024 20:38
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You're absolutely sure that you don't have the brake lights mistakenly wired into your head unit's wiring harness? Because the tail lights are 12V too. Maybe someone picked up the Reverse switch on the transmission selector wrong.
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Jan 4, 2024 22:28
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I just order a shitpile of specific grab bags from Jameco, along with an ESP32 and a small text display. I haven't really been able to get into anything because anything interesting always assumes you're a kleptomaniac with this-or-that spare just laying around. I know that's how it goes and that's even how it was with college projects, so I'm just supplementing the bits I already have with whatever-what-the-heck.
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Jan 4, 2024 22:52
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I’ve been hoarding random parts for years, as well as random dev boards and even parts recovered from old equipment. The one regret I have is that I don’t have any kind of storage system for finding it again. I have like 30 ESP32s as each time I need one for a random project I order a set of five or whatever from Amazon, then remember I did that the last few times and go and grab the one I already have.
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Jan 4, 2024 23:25
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funeral home DJ posted:Anyone have any advice on any DC filtering I could do? Would a simple capacitor and diode between the camera's power and wiring harness potentially help? Capacitors are a good first step. A 22pF ceramic capacitor across the video signal at the head unit end might be enough. If not, maybe 10uF across the camera's power and, for good measure, a 10-ohm resistor between the reverse light wire and your camera/capacitor for a little extra filtering and short-circuit protection.
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Jan 5, 2024 15:46
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A 100nF/100 ohm snubber network connected parallel to the brake light switch might help against any bursts of RF caused by the tiny spark that switch contacts can produce. If the brake lights are powered via a relay, put one over the relay switch contacts too.
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Jan 5, 2024 16:18
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ryanrs posted:I keep thinking I should build a hyperspectral LED array. It would be like an RGB LED but with more colors. So instead of selecting an [R, G, B] value, it's a 10-20 element vector. Some channels might be IR or UV. Could probably be used to differentiate different crop/tree/plant types based on spectral leaf-reflectance. The Infrared Handbook (William L. Wolfe) has a lot of spectral reflectance measurements in the visible & IR domains of various materials and plants. There's probably a million startups that have worked on variations on this idea, not sure if any of them did anything but waste money training neural networks off webcam images though. The really interesting properties probably require >1000 nm sensors & emitters though. Weird idea: tungsten/arc lamp -> diffraction grating -> DLP chip. In principle you could then synthesise any given spectrum by turning each mirror on/off like a reverse spectrum analyser.
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Jan 5, 2024 22:31
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