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172 | 172 | All individually addressable LEDs marketed as WS2811/2812/SK6812 or SK6805, as well as those claimed to be compatible with such strips are expected to work (supposedly P943S, P9411, SM16703, UCS1903, TM1804 are some examples; they are almost always mis-sold as WS2811/2812 or SK6812). I am aware of no comprehensive list - as soon as the WS281x's got popular, everyone started cloning them, abd there are in excess of a dozen (not counting examples of the identical die mounted in a different shaped package). Most of these have no english datasheet. Usually the only English on the datasheet is the timing diagram, which is an exact copy of the one WorldSemi used. |
173 | 173 | Clones that are WS2811-like (that is, it is a standard IC which must be connected to discrete LEDs constitute the majority by number of models - though it appears that WS2812-like (integrated) constitute a large majority by total quantity produced. Integrating the IC die with the LED poses some technical challenges, which caused problems when these first came out. |
174 | 174 |
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175 | 175 | These clones sometimes vary in thresholds of their timing (I have, for example, seen cases where a controller would only drive one of the two types, particularly if the oscillator is not exactly on the frequency target. I have never seen one that couldn't use the output of other "2812-alikes"). They also sometimes vary in the maximum voltage that can be seen at their outputs (12V units like the 2811 can be used to drive 3 LEDs of each color in series, at a lower current). However, with the exception of the SK6812/6805 and WS281x (as well as the APA102 and it's clones), none have achieved significant name recognition in the western world. I'm sure we're buying plenty of them - but not under their real names/part numbers. The WS2812 and SK6812 names are used almost interchangibly when finished devices are sold - regardless of which one is used (be it SK68xx, WS2812B, or some randome no-name clone). |
176 | 176 |
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177 | 177 | One thing that is worh noting is that although competent people, over time, have debated whether SK6812 or WS2812B's (the B is rarely seen in marketing material now, and I don't think non-B WS2812's are made anymore) are better, there has been no consensus. The non-B's were clearly inferior, being failure prone and requiring additional connections, and the WS2813 and WS2815 are clearly superior, with the additional backup data line and (on the '15s) 12v operation - but cost significantly more. While WorldSemi deserves some credit for originality, having been the first to make such a device, and have addressed the "old school christmas light problem" where one light goes out and the whole string after it does with the WS2813/15, the SK6812's have a much greater variety of LEDs available: They now come in in RGBW and RGBWW (warm white) 4-color versions, a WWA (Cool White, Warm White, Amber) version, and have been shrunken down to package sizes as small as 1.5mm square, and are available in side facing packages. Note that these are guesses based on the catalogs of vendors who openly sell both SK6812's and WS2812's in the same listing, which makes it unlikely that they'd be lying about the model of the IC. |
178 | 178 |
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287 | 287 | * PVC wire is almost universally afflicted with this. It is rare to purchase PVC wire from chinese suppliersand get what was advertised; I have found in the wild that the wire is typically 4 AWG thinner, but it may be as little as 1 AWG undersized to as much as 8. This does not apply western wire makers who subcontract manufacture to China - they weren't born yesterday, and are keenly aware of this trick, and keep their manufacturing partners in line. I try to avoid PVC insulated wire from China entirely. |
288 | 288 | * This is particularly troublesome when you were planning to crimp on connectors, as the insulation thickness no longer matches what the crimper and terminals expect. You can think "Okay, I need 24 AWG wire, so I'll order 20 AWG wire" to maximize your chance of getting 24 AWG wire". But to conceal their fraud, they made the insulation as thick as it would be on to 20 AWG wire: Your terminals won't fit over it! |
289 | 289 | * You know those "christmas light" style WS2811 strings? You know how you need to inject power stupidly often? The wire says 20 AWG on the side, so you really shouldn't need to inject power that often... So is it really 20 AWG? I counted 19 wires, measured each strand as 0.08mm, so it's 19/0.08, or in AWG... around 27 AWG. *No wonder we have to feed power in every 50 LEDs!* That wire is the second least honestly spec'ed wire I have encountered, being beaten by less than 1 AWG by a particularly horrible batch of prewired JST-SM connectors (the ones I mentioned above where red wire was cooked black) |
290 | | - * FEP (Flourinated ethylene-propylene, a copolymer of perflouroethylene and perflouropropylene) is a much tougher, stronger, more heat resistant material used as insulation. It is considerably harder to manufacture, but can be made thinner while having superior mechanical properties. Like PVC, however, it can still be removed with thermal wire strippers, and is not terribly hard to remove with hand strippers either. It is, unsurprisingly, more expensive. What **is** surprising is that it doesn't seem to have the undersizing problem that PVC insulated wire does. I don't know if this is just because it's harder to make and that keeps the riff-raff out of the market, or if they consider people who would buy FEP wire to be more likely to notice their bogus wire, or what the full reason is, but I've never had PVC-insulated wire arrive from China that wasn't at least 1 AWG undersized, while no FEP insulated wire has been undersized by even 1 AWG. The thinner insulation ensures that crimp connnectors will fit over the wire, even when you're pushing the upper limits of the size of wire that can fit a given type of terminal. This wire is often mis-sold as PTFE (teflon) insulated wire. Luckily they are lying about this: you don't want *actual* PTFE insulated wire. That stuff is tough as nails. It laughs at a normal thermal wire stripper, and is very challenging to strip with hand strippers as well. Stripping it easily needs a *fancy* thermal-wirestripper (and my chemical background struggles to come up with potential compounds which might make up odd-smelling fumes which wouldn't be noxious). Thankfully, little if any of the "PTFE" wire you would get buying from China is PTFE - it's all FEP. |
| 290 | + * FEP (Flourinated ethylene-propylene, a copolymer of perflouroethylene and perflouropropylene) is a much tougher, stronger, more heat resistant material used as insulation. It is considerably harder to manufacture, but can be made thinner while having superior mechanical properties. Like PVC, however, it can still be removed with thermal wire strippers, and is not terribly hard to remove with hand strippers either. It is, unsurprisingly, more expensive. What **is** surprising is that it doesn't seem to have the undersizing problem that PVC insulated wire does. I don't know if this is just because it's harder to make and that keeps the riff-raff out of the market, or if they consider people who would buy FEP wire to be more likely to notice their bogus wire, or what the full reason is, but I've never had PVC-insulated wire arrive from China that wasn't at least 1 AWG undersized, while no FEP insulated wire has been undersized by even 1 AWG. The thinner insulation ensures that crimp connectors will fit over the wire, even when you're pushing the upper limits of the size of wire that can fit a given type of terminal. This wire is often mis-sold as PTFE (teflon) insulated wire. Luckily they are lying about this: you don't want *actual* PTFE insulated wire. That stuff is tough as nails. It laughs at a normal thermal wire stripper, and is very challenging to strip with hand strippers as well. Stripping it easily needs a *fancy* thermal-wirestripper (and my chemical background struggles to come up with potential compounds which might make up odd-smelling fumes which wouldn't be noxious). Thankfully, little if any of the "PTFE" wire you would get buying from China is PTFE - it's all FEP. |
291 | 291 | * Always pull-test a few samples from a batch of prewired connectors (most commercial dupont line fails the pull test, and even some JST-SM prewired connector fails. Hopefully if you crimp your own, you're already pull testing them). |
292 | 292 | * When using pre-wired connectors, use a pin extractor to pull out a male and female pin from a given batch and compare them to a pin on the "same" connectors you already have. Proceed only with great caution and testing if you discover that the existing connectors and the ones you just got do not look identical - some terminals are made in several versions with different mating force or for different wire gauges. These both matter, but are generally designed to be compatible. On the other hand there are horror stories of incompatible male and female pins from different suppliers that would fail over time when used together, or male pins that were ever so slightly too large and would damage female terminals from other manufacturers - both could result in a poor (high resistance) connection which might get hot without causing visible symptoms until you start a fire, or notice that the wires have been discolored from heat.. |
293 | 293 | * Make sure that any power supply you use will turn itself off in the event of overcurrent, instead of changing to constant current mode. Folding back to constant current mode is great for a benchtop supply in your workshop, but in the field, all it does is waste power while generating a bunch of heat wherever the fault is, until either someone notices, something burns out, or it starts a fire. |
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318 | 318 | ## License |
319 | 319 | Unlike the core itself (as noted within the library files), tinyNeoPixel is licensed under LGPL 3, not LGPL 2.1, since the Adafruit library was always LGPL 3. |
320 | 320 |
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321 | | -`*` - C++ predates the invention of names like "properties" and "methods" (as well as countless programming concepts that we take for granted on more modern lanuages, if you haven't noticed). Strictly speaking, they are called "member variables" and "member functions" - however when you call them those names, nobody without exposure to C++ outside Arduino who didn't learn programming 25+ years ago will have any idea what you're talking about. |
| 321 | +`*` - C++ predates the invention of names like "properties" and "methods" (as well as countless programming concepts that we take for granted on more modern languages, if you haven't noticed). Strictly speaking, they are called "member variables" and "member functions" - however when you call them those names, nobody without exposure to C++ outside Arduino who didn't learn programming 25+ years ago will have any idea what you're talking about. |
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