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actionjackson posted:thanks, i'll see how much it costs to get a replacement first, or if there are other options Looks like about 20 bucks (plus unknown shipping) from these sites (I just googled "samsung fridge da41-00519R"): https://samsungparts.com/products/da41-00519r https://samsungpartsusa.com/products/da41-00519r https://www.partstown.com/samsung/smgda41-00519r I can't vouch for any of those sites but I would assume they will get you the part. There's some cheaper used pulls on ebay like this guy for 9 bucks: https://www.ebay.com/itm/394603612434 this one listed as open box for just over 10 bucks: https://www.ebay.com/itm/295597970058
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May 9, 2023 04:24
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yep, thanks again!
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May 9, 2023 04:43
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well after talking to samsung and their parts distributor, literally no one has seen this part for sale everywhere or is familiar with it, somehow. i scoured through images online, and only found it once, on some site in thailand (i cannot read thai). so for now i ordered the older version that everyone has, and if it doesn't work i can return it for a full refund. also the color temps are a trade secret?? ryanrs if this doesn't work i'll message you about sending it your way. i think the LEDs are 3x5 mm but I don't have a caliper. the little "box" it's in is around 1/8 by 1/4 inches, which is 3.175x6.35, but that's just an approximation of course.
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May 9, 2023 21:33
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actionjackson posted:also the color temps are a trade secret?? There's literally only like 5 possible kinds of LED phosphor that anyone makes that qualify as "cold white", great trade secret guys lol
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May 9, 2023 21:56
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Shame Boy posted:There's literally only like 5 possible kinds of LED phosphor that anyone makes that qualify as "cold white", great trade secret guys lol is it like 5000, 5700, 6500.... ?
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May 10, 2023 01:44
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holy poo poo i loving found it (obviously it's out of stock) https://www.shopjimmy.com/samsung-refrigerator-da41-00519r-led-lamp-assembly/ otherwise it appears to be on a russian site that has already stolen my identity actionjackson fucked around with this message at 02:30 on May 10, 2023 |
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May 10, 2023 02:18
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Design problem: Say I have a PWM square wave at a period of 30kHz, and I'd like to get as much resolution in the duty cycle as possible. Also, multiple channels. Here are some solutions: A typical microcontroller can do this, with generally around 10-11 bits of data. With just a standard PWM peripheral, the relationship is (at best) 30E3 * 2^11 =~ 80MHz clock speed. I've done it on an FPGA, but it requires a PLL - The smallest and cheapest solution is about $8 a chip for one of the Ice40s, and also needs 2(!) external clocks and flash memory and like, three different power domains, and it's huge. I've been able to get 16-bit control at 30kHz, however, which is phenomenal. But the rest of the cons are verging on dealbreaker. Now I'm toying around with doing an external PLL, and ironically, getting as low as 1.8GHz is looking almost challenging. But then how does one divide that down into duty cycle? And how much will that turbofuck FCC certs? I might try to build a ramp/schmitt trigger setup for that, but I have doubts that an analog solution like that will be: stable, thermally consistent, and repeatable across different semiconductor lots. Dedicated divider ICs? Like what? That's very fast, and a lot of external support circuitry.
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May 10, 2023 03:03
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actionjackson posted:well after talking to samsung and their parts distributor, literally no one has seen this part for sale everywhere or is familiar with it, somehow. i scoured through images online, and only found it once, on some site in thailand (i cannot read thai). so for now i ordered the older version that everyone has, and if it doesn't work i can return it for a full refund. also the color temps are a trade secret?? You can also buy the LEDs yourself from Digikey ($1 worth of LEDs + $12 shipping), then take it to a cell phone / laptop repair shop to do the actual soldering. Dunno how much that would cost, but it ought to be cheap. I can tell you which LEDs to order.
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May 10, 2023 04:26
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ante posted:Design problem: You could just use the microcontroller and add some software dither for the LSBs. That gets you absurd resolution at DC if your application can tolerate the jitter. If you can't tolerate the jitter, why not use a DAC and an analog PWM generator? Not linear enough? Add an ADC and close the loop or do some sort of calibration. Bet it's still competitive with the price of the FPGA and misc support components. Or, if you're feeling like doing something "fun", consider a hybrid approach where you configure your microcontroller's PWM signal to be open drain and add a pull-up resistor and capacitor selected so it has a quick fall and gradual rise of about 1 microcontroller clock period. Connect this to the - input of a comparator and a DAC to the + input, then the output of the comparator is your final PWM signal. So-so on linearity in the LSBs, decent on jitter, and very cheap. (E: especially if your micro has comparators and DACs built in and I know some of the AVRs do) Stack Machine fucked around with this message at 04:42 on May 10, 2023 |
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May 10, 2023 04:39
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Lighting on high speed cameras (ish) is the application, so temporal dithering is a rad solution that I definitely looked at, but had to rule out How did I now know that analog PWM generators were a thing? The LTC6662 is definitely worthy of investigation. Along the same lines, I was going to grab a switch mode power supply IC and so if I can badly abuse it for this. They're essentially the same thing. Any kind of homemade ramp generator / comparator solution would be fun, but I'd suspect too susceptible to manufacturing and temperature variance. It's possible that can be compensated for, but my analog design chops are not clever enough to be sure.
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May 10, 2023 04:57
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ante posted:Along the same lines, I was going to grab a switch mode power supply IC and so if I can badly abuse it for this. They're essentially the same thing. The SMPS designs I'm aware of control some aspect of inductor/primary current based on the control voltage, usually either peak or average. This is great for stability but it means that there isn't a voltage anywhere in the system that corresponds to duty cycle. You may find a part that does, but I've never encountered one. The term for that would be "voltage mode control". Edit: hey, cool, it turns out that a lot of manufacturers offer "voltage mode pwm controllers" where FB/VC/whatever directly controls the duty cycle and the current limit is set through a completely separate path. E.g. the UCC25705 ante posted:Any kind of homemade ramp generator / comparator solution would be fun, but I'd suspect too susceptible to manufacturing and temperature variance. It's possible that can be compensated for, but my analog design chops are not clever enough to be sure. Stack Machine fucked around with this message at 05:34 on May 10, 2023 |
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May 10, 2023 05:28
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ante posted:I've done it on an FPGA, but it requires a PLL - The smallest and cheapest solution is about $8 a chip for one of the Ice40s, and also needs 2(!) external clocks and flash memory and like, three different power domains, and it's huge. I've been able to get 16-bit control at 30kHz, however, which is phenomenal. But the rest of the cons are verging on dealbreaker. The ICE40 chips I looked at have PROM, so if you're really sure you got it right you can blow one away and it'll forever contain your shame (they claim it can't be read by electron microscope, either) so you could do away with your flash memory. You can also run VPP_2V5 at 3.3V unless you're actually *writing* the PROM (when not writing, it has the same max rating as the 3.3V VCCIO inputs). Still two power domains though, as the core runs at 1.2V and the lowest I/O it can do is 1.8V. When I used one I just had it driven by a microcontroller though, it stuffed the bitmap in via SPI each boot so I could change it later (and since it was baked into the firmware and not some random flash chip, it was also just one thing to update the whole board). I know people who've made tiny processors in those things, though, they're good fun. You could also look at the Cypress PSoC ARM microcontrollers that have toy FPGAs in them (tiny "fabric" that's more like a really fancy I/O matrix, but enough to do PWM. Also Verilog only and the IDE will fight you if you try to use C++), or the chunkier Microsemi SmartFusion2 (which also has a handy self destruct mechanism), and are both surprisingly reasonably priced (though not as cheap as the ICE40s). The small SF2s (e.g. M2S005) contain PLLs too, I think, unlike the smallest ICE40s. Edit: On the subject of doing it analogly I've seen it done with 555 timers, but I don't think that was attempting any kind of accuracy. Charles Ford fucked around with this message at 05:56 on May 10, 2023 |
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May 10, 2023 05:50
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Does anyone recognize this style of connector? It's on a 12V windshield wiper motor.
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May 10, 2023 06:04
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ante posted:Lighting on high speed cameras (ish) is the application, so temporal dithering is a rad solution that I definitely looked at, but had to rule out The lighting for the high speed camera on the thing I work at is a bog standard constant current driver IC with smoothing passives on the output and setpoint controlled by a DAC. Illumination changes frame-to-frame are still pretty small, even at 300ns exposure / 500khz frame rate (photon shot noise is most of it, which electronics can't fix)
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May 10, 2023 06:04
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TerminalSaint posted:Does anyone recognize this style of connector? It's on a 12V windshield wiper motor. Anderson PowerPole 15/45. https://powerwerx.com sells lots of that stuff.
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May 10, 2023 06:08
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Foxfire_ posted:You probably dont need anything too clever. Constant current is not an option in this particular application, although I have used it in others. I definitely have solutions that work OK. I'm just hunting for better ones. It's a harder problem than you'd think. Charles Ford posted:The ICE40 chips I looked at have PROM, so if you're really sure you got it right you can blow one away and it'll forever contain your shame (they claim it can't be read by electron microscope, either) so you could do away with your flash memory. You can also run VPP_2V5 at 3.3V unless you're actually *writing* the PROM (when not writing, it has the same max rating as the 3.3V VCCIO inputs). Still two power domains though, as the core runs at 1.2V and the lowest I/O it can do is 1.8V. Yeah, I'm certainly not brave enough to blow the PROM fuses. I know my track record with code. I had considered sideloading over SPI from a micro, but you got it, it is just one more chunk of code that has to be maintained and packaged up. And it really is physically huuuuuge. All FPGAs suffer from this, it's quite annoying. PSoCs are fun to play around with, but also no PLL, or at least the couple that I had. Or it least, not the bananas >1GHz one that the ICE40 has. Stack Machine posted:
Nice, might spin a board to play around
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May 10, 2023 06:36
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ante posted:How did I now know that analog PWM generators were a thing? The LTC6662 is definitely worthy of investigation. Dammit I almost got to suggest that (I've used it in my high voltage power supply design) but you found it first 
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May 10, 2023 07:01
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ante posted:Design problem: I'm confused by where you're getting this from? Maybe I'm just not understanding, but it sounds like you want 10-11 bits of resolution for the PWM. I used a PIC16 for my capstone project this semester and had to set up the PWM on it to control a bunch of things. Using the equation from the datasheet, you could get a 30KHz PWM signal with 10 bit resolution with a 30.6 MHz clock signal.
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May 10, 2023 07:19
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Cojawfee posted:I'm confused by where you're getting this from? Maybe I'm just not understanding, but it sounds like you want 10-11 bits of resolution for the PWM. I used a PIC16 for my capstone project this semester and had to set up the PWM on it to control a bunch of things. Using the equation from the datasheet, you could get a 30KHz PWM signal with 10 bit resolution with a 30.6 MHz clock signal. I want more than 11 bits! 16 is the goal, but particularly at low duty cycles, 14 would be good, and 13 is (from experience) pretty borderline.
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May 10, 2023 07:23
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As a very similar alternative to the ICE40 chips, you could try fiddling with greenPAKs. I haven't used the ICE40s - they appear to be smallish FPGAs. The greenPAKs are mixed signal CPLD things. They're available in some very small packages, though they are extremely small FPGAs in terms of available logic gates. They also usually have a few built in dedicated peripherals. I've used them when I want to do extremely simple discrete logic (I basically needed a toggle-able differential clock with a deadband). I hate triple 5 timers, these are way more fun to me. The only thing is I'm not sure about is how well they'll handle a really fast clock - you'll have to check the documentation, or try your luck. They also are single-shot program dealios, but you can use the chip in the programmer to test everything in circuit before you burn in the program, so the risk is very low.
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May 10, 2023 11:01
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ante posted:Design problem: Generating HRPWM via analog methods is fine until you run into certain requirements. For example, if you're controlling a multiphase SMPS then it's important that the duty cycle to each phase be very well-matched in order to ensure the phases share current properly. Analog circuits will have a very hard time with that. Dithering with a normal pwm peripheral may be an option depending on your application. It's basically a trade between bandwidth and precision. ANIME AKBAR fucked around with this message at 12:26 on May 10, 2023 |
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May 10, 2023 12:21
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ryanrs posted:Anderson PowerPole 15/45. 
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May 10, 2023 12:45
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I keep looking back at these things wondering if it's worth investing time into...quote:They also are single-shot program dealios, but you can use the chip in the programmer to test everything in circuit before you burn in the program, so the risk is very low. They have an embedded I2C interface for configuration, but at a glance it looks... bad. Instead of having one device address for the chip, it will respond to numerous addresses (not just the reserved addresses in the I2C standard). It effectively uses the first byte of the I2C transaction to determine what sort of operation is being done. So it looks very difficult to avoid address conflicts with any other slaves on the same bus. Looks like having multiple GreenPAKs on a bus is just impossible. Really weird oversight on their behalf...
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May 10, 2023 12:58
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I'm measuring a square wave frequency with an esp32 as described here (https://www.esp32.com/viewtopic.php?t=17018) and it's working but the 1s sampling period is too slow as I'd need it to be more responsive than that. It can be changed of course but it seems to be getting a bit wonky if I go to 100ms as I need to measure about 20-250Hz signals. But since the duty cycle is fixed at around 40%, is there any reason not to measure the pulse width instead? It's not PWM but the pulses have to necessarily get shorter at higher frequencies. Then the last n pulses could be averaged to get a reasonably stable and responsive result.
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May 10, 2023 13:16
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ryanrs posted:Anderson PowerPole 15/45. 
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May 10, 2023 13:26
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mobby_6kl posted:I'm measuring a square wave frequency with an esp32 as described here (https://www.esp32.com/viewtopic.php?t=17018) and it's working but the 1s sampling period is too slow as I'd need it to be more responsive than that. It can be changed of course but it seems to be getting a bit wonky if I go to 100ms as I need to measure about 20-250Hz signals. If you measure the period from rising edge to rising edge instead of the pulse width, you'd get accurate frequency even if the duty cycle isn't perfect or known. You also then get the sum part of averaging for free since the duration of N waveform periods is just the time between N+1 rising edges.
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May 10, 2023 13:38
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Stack Machine posted:If you measure the period from rising edge to rising edge instead of the pulse width, you'd get accurate frequency even if the duty cycle isn't perfect or known. You also then get the sum part of averaging for free since the duration of N waveform periods is just the time between N+1 rising edges. Good idea, thanks! I'll try it out later today.
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May 10, 2023 15:51
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Speaking of FPGAs, last year I built a video upscaler using the Lattice Mach XO2 1200HC and it was very convenient to build a PCB with. Built-in flash, oscillator, PLL, runs on 3V3 power, LQFP package, etc. Literally all that's needed are bypass caps lol. They're about $8 each, $6 in 25+ quantities Spatial fucked around with this message at 16:24 on May 10, 2023 |
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May 10, 2023 16:22
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i think the kapton tape i got, even at just one layer, was too... yellow. here i put one piece under one microwave light, and nothing on the other, and it's a huge difference. if there was a kapton tape that was just a very light yellow, that might work, but i think the only colors are gold and amber i know people offered to help with soldering, and i appreciate that, i just like this because i can always take off the tape if I don't like how it looks. if i knew what the luminosity and the color temp of these lights were, that would help a lot.
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May 11, 2023 02:51
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what is this, some extended refrigerator science project? just match the color temp of your room lights and move on with your life.
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May 11, 2023 03:00
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ryanrs posted:what is this, some extended refrigerator science project? just match the color temp of your room lights and move on with your life. 2700k would be awfully low for a fridge
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May 11, 2023 03:04
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it'll bring out the rosy complexion of your refrigerated ham products
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May 11, 2023 03:07
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ryanrs posted:what is this, some extended refrigerator science project? just match the color temp of your room lights and move on with your life. He's been on this for literally six months lol Spatial posted:Speaking of FPGAs, last year I built a video upscaler using the Lattice Mach XO2 1200HC and it was very convenient to build a PCB with. Built-in flash, oscillator, PLL, runs on 3V3 power, LQFP package, etc. I've used Mach XO2 a bunch of years ago, I'm not sure why I didn't consider them this time around. Supply chain issue maybe. Maybe I will dig into this again, it looks promising. ANIME AKBAR posted:There are a few types of microcontrollers with high resolution pwm modules which should fulfill your requirement. C2000 is the one I've used extensively, I'd recommend something like the F280049. Typical timing resolution is around 150ps. Some Kinetis (I think KV4 and KV5) and XMC parts also have similar features. I think a couple dspics also do. Yeah, I can't do dithering. Also my main microcontroller is basically fixed. It's not impossible to add another micro, but definitely a little finicky. Just like adding an FPGA, I guess. I've been combing through the appnotes on the ePWM peripheral, and it's definitely interesting. Also, insanely complicated, and I think getting a devboard would be the fastest way to determine suitability. Splode posted:As a very similar alternative to the ICE40 chips, you could try fiddling with greenPAKs. I haven't used the ICE40s - they appear to be smallish FPGAs. The greenPAKs are mixed signal CPLD things. They're available in some very small packages, though they are extremely small FPGAs in terms of available logic gates. They also usually have a few built in dedicated peripherals. greenPAKs have intrigued me for years, but the breaking into the ecosystem seems like a really time consuming task
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May 11, 2023 03:26
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ante posted:He's been on this for literally six months lol i just revisited it after taking a break for a while sorry i'm kind of OCD, i'll stop posting about it
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May 11, 2023 03:28
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actionjackson posted:i just revisited it after taking a break for a while Please don't stop, this is quite amusing.
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May 11, 2023 03:56
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ante posted:greenPAKs have intrigued me for years, but the breaking into the ecosystem seems like a really time consuming task The initial EVK is expensive for a hobbyist,, but the programming software is pretty good, and the built in simulator let's you just mess around with it until it works. It took me one or two work days of messing around with it until I was pretty comfortable with it. In your case though I'd want to deep dive the documentation before I committed, I've had problems with running greenpaks at higher speeds once before
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May 11, 2023 03:58
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actionjackson posted:i just revisited it after taking a break for a while i mean i also am pretty picky about the color of the lights in my house, and also on my electronics, to the point where i have a drawer full of red LEDs in all different SMD sizes so that I can replace the annoying blue and white ones that are in every device these days with nice soothing non-glaring red. you just need to learn to solder.
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May 11, 2023 04:02
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Or pick up a Rosco gel swatch book
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May 11, 2023 04:21
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ante posted:Or pick up a Rosco gel swatch book whoa that's cool as hell
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May 11, 2023 04:46
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ante posted:I've been combing through the appnotes on the ePWM peripheral, and it's definitely interesting. Also, insanely complicated, and I think getting a devboard would be the fastest way to determine suitability. You'd definitely want to start off with one of their example projects first. Mouser has the basic eval board in stock. The bottom line with C2000 MCUs is that they have incredible analog/PWM peripherals. But if you're not going to make use of any of its unique features, then don't bother, get something more general purpose instead. ANIME AKBAR fucked around with this message at 13:26 on May 11, 2023 |
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May 11, 2023 04:55
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