Fancy some fishy-chips? Just order one of these sensors: Research shines light on suspect component sources If you're looking for cheap electronic sensors, the internet has lots of possibilities, but buyer beware: they aren't always exactly legit. Since 2018, Christian Petrich, a researcher with Northern Research Institute in Narvik, Norway, has purchased more than 1,000 temperature sensor chips from more than 70 vendors via eBay, …
Well the solution appears to be simple : stop sourcing from Chinese websites.
You can't get the counterfeit stuff off ? Who cares ? Don't use their websites, and leave the Chinese to buy sub-par, inaccurate hardware.
One day, the Chinese themselves will be fed up with the situation, and that's when things will move.
In the mean time, just don't buy on Chinese websites.
Depends, I suppose, on what your accuracy/reliability/price tradeoff equation looks like.
In my (admittedly limited) experience with direct-from-China traders, I've not been happy with the quality, and consider it money wasted. Tag is for what they do, usually sooner rather than later.
Just replaced my Adafruit BME280 (€22,95). Stopped working after two years.
When looking in my mail to see when I bought it, I saw the first one I got was DOA and had to replaced instantaneously. Meanwhile all my cheap Chinesium chippies are ticking along.
Not to say that many "UK sellers" in Amazon, eBay and NewEgg are simply fronts for Chinese sellers (read: repackagers of used or stolen electronics as new, or peddlers of counterfeit chips). Some of them will even list addresses of UK shipping warehouses or invalid addresses (most people won't check). Not to say that a valid UK address means valid sellers, the front is much better camouflaged.
Unless you buy from the original manufacturer - which you can't do unless you are buying very large quantities - you can't be sure whoever you are buying from (or whoever they bought from) didn't buy from a shady source.
When you are an ordinary person buying in quantities of one or a few, there is nowhere you can buy from and be certain you are getting the real thing.
Not a trademark violation (searched on DS18B20 trademark shows nothing, and no 'tm' on the chip next to its designation)
Not a copyright violation (the dies are different)
Not a patent violation (ancient chip).
When I search Aliexpress for "DS18B20 temperature probe" there are plenty, but none of them claim it is the Maxim chip and DS18B20 is as generic as NE555 is to timing chips, or AA is to batteries. Is an AA battery a counterfeit? I don't know who owns the trademark even.
As for this: "Among the sensor chips analyzed, Petrich speculates some were stolen from the Maxim production line, some are less accurate than they should be in their temperature calculations"
Seconds are seconds. Nobody is going to break into a factory and steal chips worth pennies, and happen to only steal the sub-par chips that just happen to be lower spec ones!
A more usual thing: they test them, the out of spec ones are sold as seconds, sold off to crappy cheap temperature probe makes who knock out $0.83 temperature probes. You then buy those probes and spend a lot of time checking they don't meet Maxim's spec and then writing a lot of words.
Maxim just popped up in a buyout feed, so now I am really suspicious about the timing and subtext here:
https://www.bloomberg.com/news/videos/2020-07-13/analog-devices-ceo-on-buying-maxim-integrated-video
"Analog Devices Inc. agreed to acquire rival Maxim Integrated Products Inc. for $20.9 billion in stock, heralding what may develop into a new round of consolidation in the $400 billion semiconductor industry."
Handy to have an article fluffing an ancient chip, long replaced by generics as if it was super-valuable hi-tech, at a time of a buyout of said maker, no??
I think the problem was that people were conned into thinking they were buying a new chip from the original manufacturer but ended up buying a clone or used chip (or both?). Let me be clear on this: No Amazon or eBay seller will miss the opportunity to flip a clone or used chip as "new and from original manufacturer" if it bumps the price by a dozen quid or so. There is no real punishment from doing so. If possible, buy directly from the manufacturer or directly from Amazon (not "fullfilled by Amazon").
No Amazon or eBay seller will miss the opportunity to flip a clone or used chip as "new and from original manufacturer" if it bumps the price by a dozen quid or so. There is no real punishment from doing so.
When a buyer flags you for it, you end up refunding the full amount, and losing the merchandise. And after a few rounds of that, you'll be delisted from the site. Not a massive penalty, but long-term it's more profitable to be honest and only mention that it's similar to or compatible with Name Brand X.
The "DS" in DS18B20 is for Dallas Semiconductor, now Maxim.
The "NE" in NE555 is for Signetics, now part of Texas Instruments.
There is also an LM555 which is National Semiconductors' version, now part of Linear Technology Corp.
These are not generic part numbers.
A relative used to work for a mobile manufacturing company. Counterfeiting of both phones and accessories was a big issue. Some of the counterfeit items had counterfeit holograms also; he told me that the counterfeiters buy the holograms from organized crime groups.
One time, while visiting one of their Chinese sites, he discussed the need to ship a CD with a product. He gave one of the local folks a DVD case and asked for a supplier for "something like this". A couple days later, the guy came back with the original DVD case and an identical replica... down to the US patent number...
About 15 years ago we built a batch of 500 amplifiers using a front-end chip AD sourced in the USA and every unit failed the testing - we worked on the diagnosis for a month and eventually returned the rest of the chips from the batch to the manufacturer, Analog Devices who reported them all as fakes and provided x-rays of their chips and our chips - they were radically different internally but identical on the outside.
If it's not shipped directly from the manufacturer or directly from Amazon (and not "fulfilled by Amazon", that's a different thing) assume it's a fake or used item. There is an entire industry both when it comes to counterfeiting electronics and when it comes to recycling a used (or even stolen) electronics to "new" status. I had supposedly "new" and "factory sealed" HTC One M8 phones ship with a Windows Mobile manual from an HD2 (all of them from high-rated Amazon sellers and fullfilled by Amazon). There is an entire industry when it comes to re-selling old sound card chips and old RAM modules and cloning them (but selling them as geuine made from Yamaha or Samsung accordingly).
It's also why so many Chinese phone resellers are butthurt from a recent Apple decision which closed a loophole which allowed iPhones to have their device lock removed by entering service mode, because it makes it harder to flip stolen iPhones as refurbs or even new. You see, it's easy to ask the legitimate owner for the unlock code but very hard if his iPhone was stolen from them.
In the 1970's the CIA sold defective electronic equipment to the Directorate T of the Russian KGB. This well known fact is described in the Farewell dossier.
> some lack features like support for using parasitic power – using power even if a device is turned off
Parasitic power on 1-Wire networks is actually quite clever; as the name implies these devices can run off a single wire for both data and power (some kind of ground reference also needs to be available of course). The chip charges an on-board capacitor with enough power from the data line (during a 750ms preamble) to wake up, execute the request, and return the response. In other words, such a device can run off the whiff of an oily rag, and draws zero power when idle. Originally envisaged by Dallas as a "MicroLan" for all manner of ultra-low power devices, 1-Wire today is mostly used for temperature sensors and ID tags (like the ones many waiters carry on a retractable keychain, and use to identify themselves at the till, a.k.a. "iButton"). This is a shame, because it's pretty cool technology, especially for the power conscious. That said, there are still a few 1-Wire enthusiast suppliers around, such as HomeChip and Sheepwalk Electronics. Check Wikipedia for more info about 1-Wire.
Seems that even completely obsolete (eg SHT11 and BMP085) sensors are being cloned and sold.
The gotcha is that the temperature part will work just fine but humidity or pressure reports a static value or one that tracks to temperature.
The amount of effort they went to is considerable when a genuine chip isn't even that much to begin with.
Another well known method is to use a cheap micro internally that feeds back plausible values having no bearing on reality.
If this chip happens to be a battery charger or amplifier voltage feedback IC, "Bad Things" (tm) can and probably will happen.
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