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Trabant posted:edit: also, I badly need some better probes and leads for my bare-bones multimeter and power supply, goddamn this is PITA to work with. Is that chip a combined CPU+LCD, or is the display separate? The valuable parts if you end up replacing the PCB and just want something functionally equivalent are the satisfying/reliable buttons and a display that fits the case. The CPU is easily replaced by a modern microcontroller.
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# ? Oct 11, 2022 20:20 |
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# ? May 9, 2024 17:36 |
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Thanks for the recs! Re: LCD and chip, they appear to be discrete as there's a sizeable gap between the LCD and the front of the board (with the chip on the back): And yeah, finding a new perfectly fitting screen (40mm x 18mm) isn't something I have high hopes for. I wouldn't even want to guess as to how I would separate the screen if it came to that though, I've never even attempted that kind of thing.
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# ? Oct 12, 2022 01:37 |
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Well you guys were right about the valve configuration, I should've looked at it closer after it was mentioned. There is a third port on the push button that exhausts after you let go. So it's a manually actuated 3/2 valve I think. On the other hand I was able to make the valve I bought actuate using the PLC so I'm on the right track there. It just gets stuck open after it cycles. On that note, I think this is what I should be looking for in the correct valve? The PLC is outputting 120VAC, not DC like I said earlier. https://www.automationdirect.com/adc/shopping/catalog/pneumatic_components/directional_control_solenoid_valves/solenoid_valves/avs-3312-120a
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# ? Oct 12, 2022 15:38 |
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A Proper Uppercut posted:Well you guys were right about the valve configuration, I should've looked at it closer after it was mentioned. There is a third port on the push button that exhausts after you let go. So it's a manually actuated 3/2 valve I think. If the PLC is 120VAC, then yes that valve/actuator combo is correct.
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# ? Oct 12, 2022 16:02 |
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Stack Machine posted:Those power values are also only given as typical so they don't constitute a guarantee. Meanwhile, just down the datasheet is a max THD spec at 1W into a 4 ohm load of only 0.06%. That means that with a fresh part in that configuration, if you measure more THD than that you can call up a sales rep, return it, and make some engineers sweat. Comparing OpenSCAD to LaTeX is brilliant. This is the perfect analogy.
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# ? Oct 12, 2022 19:23 |
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I've got a Halloween prop that I bought a couple years ago that has an apparently failing motor. It's a clown that's supposed to sway back and forth, but it only works for a few seconds before stopping. I disengaged the motor from the rest of the prop to see if it would keep running without any burden on it, and it runs for a little bit longer before sputtering out. It starts to whine, then stutters, turning very jerkily for a few seconds, and then completely dies. The length of time it runs changes based on how long it's unplugged for between attempts. Is it overheating? I've got video if it helps, but it's basically just what I've described here. Any chance popping it open and throwing some grease in there might help, or is this just symptoms of a dying motor?
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# ? Oct 13, 2022 00:53 |
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Slugworth posted:Any chance popping it open and throwing some grease in there might help, or is this just symptoms of a dying motor? Good to very good. Try light oil first, then grease.
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# ? Oct 13, 2022 01:11 |
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Clean it with some alcohol while you have it apart, it's probably all gunked up. I have a desk fan that every few years requires taking apart, cleaning, and re-lubricating the motor, but after I do that it works like new for another few years.
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# ? Oct 13, 2022 03:24 |
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Shouldn't we be paying attention to what we use to lubricate what are likely plastic gears? E: I like keeping a tube of superlube around. CopperHound fucked around with this message at 03:34 on Oct 13, 2022 |
# ? Oct 13, 2022 03:28 |
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CopperHound posted:Shouldn't we be paying attention to what we use to lubricate what are likely plastic gears? I like to lube plastic mechanisms with acetone personally
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# ? Oct 13, 2022 03:41 |
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Clown's haunted, find a priest or a skeezy university professor with a side hustle
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# ? Oct 13, 2022 03:52 |
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A Proper Uppercut posted:Well you guys were right about the valve configuration, I should've looked at it closer after it was mentioned. There is a third port on the push button that exhausts after you let go. So it's a manually actuated 3/2 valve I think. These are automationdirect's twist-to-release push buttons. You mix-and-match a button kind, mounting adapter, and separate valve. I think they only make the valves for them in 5/32 though, so that specific series of parts might not work for you.
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# ? Oct 13, 2022 04:23 |
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Splode posted:I like to lube plastic mechanisms with acetone personally Eh, just throw some WD-40 on it dont do this
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# ? Oct 13, 2022 04:54 |
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So I got this soldering practice kit working last night: https://i.imgur.com/yzyxYK1.mp4 Then I looked at the instructions and they said this: Does anyone want to look at the schematic and tell me which joints I should be looking at to get the lights looking like figure 2?
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# ? Oct 13, 2022 06:37 |
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That's a fun riddle. Unfortunately, the answer is that it's just a set of SIPOs and latches, so essentially the only thing that could go wrong there is in the STC89's firmware edit: Double check those resistor networks though, RP1-8 ante fucked around with this message at 06:51 on Oct 13, 2022 |
# ? Oct 13, 2022 06:47 |
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Yeah those resistor networks are very annoying to solder, I'll focus on them.
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# ? Oct 13, 2022 06:57 |
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After soldering the resistor networks and a million other things and getting no change, I went and had a look at main.ccode:
code:
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# ? Oct 13, 2022 08:44 |
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Foxfire_ posted:If it doesn't already have one and you're buying more stuff anyway, add a manual valve to the incoming supply line so there's an easy way to make it stop doing things without waiting out the cycle / if the software's messed up and is constantly triggering it. There's a big ole shutoff right at the incoming air input on the setup I bought, appreciate the looking out though.
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# ? Oct 13, 2022 09:49 |
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If you look at how those shift registers connect to the buffers, you can clearly see Q0->1D Q1->2D, Q2->3D, Q3->4D But then it reverses and goes Q4->8D, Q5->7D, Q6->6D, Q7->5D. And then it appears just looking at the PCB the LEDs run straight off the buffer outputs pin-by-pin. So I don't see how it would expect to work unless you account for that in the step order. I would expect you'd have to do something like: code:
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# ? Oct 13, 2022 17:51 |
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Had a thought today and couldn’t figure out the answer. How come there aren’t really any exponential converter ICs? Those circuits are complex enough to be worth abstracting to a chip. Are they just not very common?
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# ? Oct 13, 2022 18:03 |
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You could say that about any number of circuits involving an op amp and a handful of jelly bean components. Hundreds, probably. There are too many application specific values that you need to choose for yourself, in addition to deciding how good (expensive) you need your op amp to be. The age of an IC existing for everything came about around the same time that credible DSP microcontrollers started existing, too. The eurorack stuff is still firmly in the age of 7400 series logic
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# ? Oct 13, 2022 18:15 |
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Rescue Toaster posted:If you look at how those shift registers connect to the buffers, you can clearly see Q0->1D Q1->2D, Q2->3D, Q3->4D So it would look like this? I guess what i'm really worried about is whether it should be one light turning on at a time (like I have now) or multiple lights turning on like in the instructions (Figure 2):
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# ? Oct 14, 2022 00:38 |
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What do you think should happen, given that code and circuit? Follow the data
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# ? Oct 14, 2022 00:45 |
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Yes the lights are doing exactly what I would expect given the schematic and the code you showed. I don't see anything out of place that would indicate soldering problems. The code is shifting a single bit (Just a 1) over by different amounts, so you'd just see a single light on at once. And if 0xFF (1111 1111) is everything on, it should be 0x55 or 0xAA that would produce the 0101 0101 or 1010 1010 pattern, no? And nothing in the code is doing that. The instructions are just bad.
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# ? Oct 14, 2022 01:38 |
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Thanks for that. Mystery solved I guess.
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# ? Oct 14, 2022 01:46 |
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Congratulations on your correct welding
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# ? Oct 14, 2022 03:48 |
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If anyone is interested, I'm developing a Bear Radar to guard my picnic basket while camping in my minivan. It's a network of radar + thermal motion sensors that chat with each other over radio. The idea is to go full sci-fi / heist movie with the design. Each sensor node has: Nordic nRF52840 ARM processor Bluetooth LE 900 MHz LoRa radio U-blox GPS BNO055 orientation sensor (up, north) Passive IR motion detection Radar LED floodlight My plan is to set up a few nodes around my campsite in the evening. They'll watch my stuff and compare notes over 900 MHz. If they see a bear, they can wake me up and I'll scare it away. It is, of course, ridiculously over-engineered because it incorporates every cool module I've ever wanted to play with. It's basically a sensor + radio dev board. And although I don't plan to, it should be possible to port Meshtastic to this hardware pretty easily. So far I've hand-soldered one board and it seems to work ok, so I'm putting together all the files to get another 10 made in a factory. That includes the BOM, pick and place data, test and debugging docs, etc.
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# ? Oct 16, 2022 02:20 |
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How will this system differentiate a bear from, say, a raccoon
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# ? Oct 16, 2022 02:28 |
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I also would not want a raccoon stealing my pic-a-nic basket so that might not actually be a problem
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# ? Oct 16, 2022 02:34 |
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You just have to change the alarm sound from "Warning: Bear detected!" to "Warning: Bear or an animal with similar food stealing tendencies detected!"
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# ? Oct 16, 2022 02:36 |
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It won't be able to tell the difference between a bear, human, deer, or probably a raccoon. But that's fine. I don't want raccoons in my stuff either (though they probably won't open containers, these are wilderness raccoons, not professional suburban raccoons). It would only be annoying if it triggered on mice or small birds. I think I can set detection limits to avoid very small animals, though. e: it can also ID vehicles since the radar measures speed and direction (only towards/away, not full vector).
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# ? Oct 16, 2022 02:36 |
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Cojawfee posted:You just have to change the alarm sound from "Warning: Bear detected!" to "Warning: Bear or an animal with similar food stealing tendencies detected!" Still seems too specific, what if it’s a curious Bigfoot? Or murderous Wendigo? The message needs to cover all possibilities.
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# ? Oct 16, 2022 02:37 |
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Sorry, an nvidia jetson will not fit within my power budget.
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# ? Oct 16, 2022 02:43 |
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There are a lot of people who would pay a hell of a lot of money for a radar system capable of positively identifying a bigfoot
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# ? Oct 16, 2022 02:44 |
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What about the turrets? https://www.youtube.com/watch?v=Ss35wHcN6iQ
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# ? Oct 16, 2022 02:50 |
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Automated bear spray turret
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# ? Oct 16, 2022 02:57 |
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Remote controlled ultrasonic humidifier full of dog piss.
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# ? Oct 16, 2022 03:02 |
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ryanrs posted:If anyone is interested, I'm developing a Bear Radar to guard my picnic basket while camping in my minivan. This reminds my of my bagpipe project. During every step of the way I am considering how I can make a whole lot of these, thinking about ease of assembly and durability of components during assembly. I'll probably wind up making a total of 1 if I'm lucky. I salute you, fellow uber-engineer.
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# ? Oct 16, 2022 21:50 |
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I find it kinda fun to think about designs in a "well what if I want to make a thousand of these?" or "what if I want other people to build this?" way even if I'm 100% sure I'm gonna make one, maybe two (if I break the first one). Like all my designs have specific board revisions and dates, the schematics have notes wherever something's not perfectly clear, and I try to streamline stuff and use "standardized" components (as in ones I have thousands of) so when I'm building it I can just pour out like 50 of the same resistor on my desk instead of having to go back to the parts bin every 10 seconds, etc. At least it's come in pretty helpful the like, two or three times I've had to completely re-spin a board cuz I hosed the design up so much I couldn't just bodge it
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# ? Oct 16, 2022 22:16 |
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# ? May 9, 2024 17:36 |
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That one guy who does fine art restoration on youtube does stuff like carefully tuck and fold corners of canvas behind the stretcher, then tack them in place out of sight, which he explains: "Why go through all the trouble? Nobody will ever see it and it doesn't have any effect on the front that people actually look at. But I know it's there." I feel like a lot of my electronics designs are along those lines.
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# ? Oct 16, 2022 22:20 |