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Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

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Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#91

Post by tgsovlerkhgsel »

as-j wrote: post #6

This affects temperature sensors/parts bought from un-official distributors like ebay or AliExpress, not digikey, farnel, etc. Perhaps I've been too lucky in my career and practiced EE for work, but who would you ever go to ebay instead of digikey?? Digikey certainly has a premium, but their speciality is small numbers/cut tape/etc and they have a small order size which makes them ok for hobby work, and I've used the…

I live outside the US.

Both Digikey and Mouser will charge me $20+ to ship anything (tried with a small capacitor). Farnell will let me put stuff in the shopping cart, then when I select "individual" as the customer type, tells me that they only ship to companies and redirects me to a "partner site" for individuals, which promptly fails to load (things like this have conditioned me to avoid official distributors). RS will gladly sell me 4000 of those capacitors.

For a hobbyist outside of the US, AliExpress is often the only realistic source aside from the local RadioShack equivalent which probably doesn't have what you need.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#92

Post by Gibbon1 »

mindslight wrote: post #75
metaphor wrote: post #68

Earlier quoted context omitted.

I understood that joke to mean, "Maxim components are so expensive that the grey market is about the only place the layman can afford them in more than 1-off prototype quantities." At least that was my experience 8 or so years ago when I made the mistake of purchasing a lot of 100 MAX7219 off eBay for $100 shipped from China...$1/ea was such a tempting deal to a younger, more naive self when these chips were selling…

No... there was a time when Maxim parts weren't really available through the major distributors. They had one of the most generous sample programs, but apart from that they seemingly wanted to draw you into some heavyweight direct sales process based around millions of parts per year. As the things I was designing were mostly aiming for quantities in the thousands, it made me not even bother considering their parts.

I'm wondering when that was. I remember basically always being able to get parts through normal distribution.

Motorola microcontrollers on the other hand.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#93

Post by 0x402DF854 »

metaphor wrote: post #82
0x402DF854 wrote: post #42

I've bought ~100 of these sensors from ali and ebay and 9/10 had troubles reporting temperatures in passive mode reliably. However simply repeating requests until sensor reports a valid value (!=+85C and !=-127C) works fine. Rarely I've seen sensors not working in passive mode at all. Still, I always recommend running an extra +VDC wire (3 wires vs 2 wires isn't a big inconvenience). When running large 1-wire buses (…

> However simply repeating requests until sensor reports a valid value (!=+85C and !=-127C) works fine. You know you're dealing with counterfeits and you know they're unreliable, but you've somehow convinced yourself that despite all the uncovered variance sitting on the table, if you keep poking long enough until the component returns some non-edge-case value, then it "works fine". I must have hopped on the sanity t…

You are indeed missing something here :)

Long 1-wire networks are notoriously unreliable [1]. Something that works fine today can stop working tomorrow. That doesn't mean that they shouldn't be used anywhere. They have their niche.

If I want my heating system monitor to report temperatures once per hour and it takes me 5 tries and 10 seconds to read a sensor, I call it good enough. If monitor doesn't succeed after 20 retries, it sends an alert to replace the sensor (so far that only happened due to damaged wiring, not the sensor itself).

It is possible (and quite fun) to build reliable systems using somewhat reliable components :)

[1] https://www.maximintegrated.com/en/design/technical-document...

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#94

Post by julianz »

fermienrico wrote: post #53
godelski wrote: post #14

Earlier quoted context omitted.

Lots of hobbiests will buy things off ebay, Amazon, or Alibaba. It is extremely common and if you go into forums it is even encouraged. I'm not saying you should go to those places, but that lots of people do.

We've spoiled ourselves with CCP subsidy. It wasn't like that about 20 years ago. You'd pay a pretty penny for things and support local/national businesses. Now, you're funneling fuel into the dragon's mouth. For what? A hobby project? Just spend the $7 shipping and get it from Digikey.

Just went to my local Digikey site. Shipping is $20 USD or $26 NZD.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#95

Post by jbay808 »

tgsovlerkhgsel wrote: post #91
as-j wrote: post #6

This affects temperature sensors/parts bought from un-official distributors like ebay or AliExpress, not digikey, farnel, etc. Perhaps I've been too lucky in my career and practiced EE for work, but who would you ever go to ebay instead of digikey?? Digikey certainly has a premium, but their speciality is small numbers/cut tape/etc and they have a small order size which makes them ok for hobby work, and I've used the…

I live outside the US. Both Digikey and Mouser will charge me $20+ to ship anything (tried with a small capacitor). Farnell will let me put stuff in the shopping cart, then when I select "individual" as the customer type, tells me that they only ship to companies and redirects me to a "partner site" for individuals, which promptly fails to load (things like this have conditioned me to avoid official distributors). RS…

A lot of the time, these struggles are invisible to those living in the US. It's similar with McMaster-Carr; typically an American hobbyist will ask why one would look anywhere else for hardware parts, not knowing that (at least for many years) they would only ship to corporate partners for orders outside the US.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#96

Post by voltagex_ »

analog31 wrote: post #72
kregasaurusrex wrote: post #36

Trust in hardware supply chains when manufactring a PCB for a product can be quite fragile: when one component operates outside of spec, the entire device could be rendered useless. In the case of the DS18B20, the author states in the 'Warning' section that the primary way of determining counterfeit sensors is to check the ROM output compared to a known format. When counterfeit parts like this are added, it creates v…

If I recall correctly, FTDI took some well deserved heat, but quickly discontinued this practice.

Both FTDI and Prolific have done this kind of thing. I switched to the CH340 a while back without any issues.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#97

Post by fpgaminer »

fermienrico wrote: post #51
IgorPartola wrote: post #32

Earlier quoted context omitted.

This. I buy a decent amount of hobby electronics from eBay and AliExpress because yes it is cheaper. When I need quality, Mouser, DigiKey, and McMaster-Carr are there for me. But the minimum $7-9 shipping is the main reason is forego them. I’d gladly pay 2x for small electronic components (vs directly from China options) if shipping wasn’t a problem.

For any serious person trying to develop a little bit beyond hobby projects: Think about an hourly rate of $80/hour for yourself. If you have to spend an hour trying to fiddle with subpar shady parts, you've already paid for the shipping 8 times over. Also, it is painful to wait for these packages from China. Digikey ships same day and its at your door step in the morning (I overnight it) and if you use $7, it is usu…

> But even then, you can bundle all your parts and order once.

I fall for this trap every. single. time.

_HOURS_ spent racking my brain to think of all the things I might need in different scenarios, so I can be absolutely, positively, 100% sure that I have everything in that one single order.

... and end up placing 2 to 3 more orders before the project is done.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#98

Post by toohotatopic »

LeifCarrotson wrote: post #76
robomartin wrote: post #58

Earlier quoted context omitted.

> This anti-consumer behavior on behalf of companies I strongly disagree with this. I see no way to rationalize that a company should be responsible for ensuring that counterfeit devices work correctly by releasing drivers that are tolerant of them or do not stop them from functioning. FTDI's products are the combination of their hardware with their drivers. Both are required in order to delivery functionality and re…

I agree that anyone who built a device and knowingly used a counterfeit FTDI chip deserved to be punished. However, the FTDI debacle didn't punish those people, they're not the consumers. It punished end users who have no idea what an FTDI chip is or does or that one exists in the products they buy. In your airliner microcontroller example, you have much more informed consumers. They could reasonably be expected to k…

>People don't know what their packaging is made from or who it's made by. They have no way to verify it prior to purchase, and even after purchase, it would take an expert to identify.

For food, you can't change the game without prior notice, but if it is clear that faked goods are toxic, people would start buying from trusted providers themselves. For electronics, I don't see a problem. If a device is bricked, go to your dealer and let him replace it. He will do the same for his supplier, etc.

Somebody in the chain will discover that his supplier is a fraud. He will have to swallow the costs, but has learned a valuable lesson.

If people have brought the product from some unstable source, then they most likely got it cheaper and they are now paying the price for the increased risk they took. It doesn't feel good but I don't think that it is unfair.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#99

Post by dejv »

unnouinceput wrote: post #79

I don't get it. Why bother faking something that is very cheap to make genuine? I mean you pay peanuts for real deal, and you want to make something even cheaper then that?...why? Where is the profit?

Well I guess when you invest in purchasing fab you want it utilized as much as possible, so you might want to add batch here and there when you dont have contract work.

Re: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

#100

Post by coupdejarnac »

mindslight wrote: post #33
as-j wrote: post #6

This affects temperature sensors/parts bought from un-official distributors like ebay or AliExpress, not digikey, farnel, etc. Perhaps I've been too lucky in my career and practiced EE for work, but who would you ever go to ebay instead of digikey?? Digikey certainly has a premium, but their speciality is small numbers/cut tape/etc and they have a small order size which makes them ok for hobby work, and I've used the…

How else can you get anything from Maxim besides samples? (joke may be a decade out of date)

From what I've seen recently on r/ece or r/electronics, can't remember which, that's still a huge issue.
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