Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

github.com

Post reply on HN
Print view View original

201–210 of 239 posts

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

#201

Post by uep »

myself248 wrote: post #12
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'd never expect to find these in official products from trusted brands, but off-brand crap? Oh yeah. DIY kits? Absolutely. The parts drawer at the makerspace? One hundred percent. So much stuff on eBay is free shipping, that's huge when you only need a few dollars worth of stuff. If I could convince Digi-Key to lick a 55-cent stamp when I need ten of something, instead of charging me $7 for shipping, I'd have a lot…

I think this is about to change. The Chinese shipping will go up. A couple weeks ago, there was an article posted here about why shipping from China is so cheap, epacket[1]. Because of epacket, it was cheaper to ship from China than it was to ship to even within the same state for small packages.

A recent change allows the USPS to increase rates for epacket. It looks like the new rates will go up slowly, so shipping from China will still be cheaper for packages under 3 ounces for a few years.

[1] https://www.ecomcrew.com/why-china-post-and-usps-are-killing...

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

#202

Post by joshvm »

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…

> If you're a business, there is absolutely no excuse to penny pinch here.

Most of these sites offer free shipping to trade accounts with no MOQ as well.

But also you want that customer service as a business. Mouser once sent me a replacement camera at work (university) because they supplied one with the wrong interface. No doubt we have a big order book, but I've had similar experiences with RS as a hobbyist customer - ordered tools which are not up to scratch or slightly out of tolerance - "just keep it, we'll send a replacement".

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

#203

Post by paulie_a »

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…

Some medical equipment works the same way in my experience. A nurse or I will routinely ask to redo a reading because the value "didn't seem right"

And sure enough that happens about 1/3 of the time regardless of equipment or facility.

So "just doesn't feel right" is something that absolutely happens in the real world. Not taking that into account is sloppy engineering

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

#204

Post by mrob »

robomartin wrote: post #58
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…

> 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…

It is impossible for the FTDI driver to reliably determine if a chip is counterfeit. The difference between a counterfeit and a compatible part is trademark violation, and that can only be detected by looking at the physical packaging and the marketing materials.

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

#205

Post by VLM »

Gracana wrote: post #56
myself248 wrote: post #12

Earlier quoted context omitted.

I'd never expect to find these in official products from trusted brands, but off-brand crap? Oh yeah. DIY kits? Absolutely. The parts drawer at the makerspace? One hundred percent. So much stuff on eBay is free shipping, that's huge when you only need a few dollars worth of stuff. If I could convince Digi-Key to lick a 55-cent stamp when I need ten of something, instead of charging me $7 for shipping, I'd have a lot…

Hmm, I was going to say that digikey has 3 or 4 dollar shipping, but I checked and it's $5 for a first class mail. Maybe they've changed it, or maybe it's COVID-related. I recall that they had a low price for shipping of a small maximum weight, which was good for little orders of just a few components. I generally just suck it up and place the order regardless of the shipping cost, it's not great to spend as much on…

I pad my order by adding expendables, stuff I know I'll use a lot of. There's a certain kind of end-fed SMA pcb connector I use a lot of. Solder. Flux. Certain JST-type connectors.

I also keep a "gift list" for myself of things I've always meant to experiment with but haven't gotten around to ordering. I ended up playing with MSP430 controllers this way.

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

#206

Post by VLM »

In the old days if you wanted sweepings from the factory floor you shopped at Radio Shack. Usually worked well enough anyway. Just like ebay or amazon today, usually.

I've had worse luck with assemblies than components; switching supply modules from ebay / amazon don't come with decoupling caps or RFI inductors or RFI chokes.

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

#207

Post by phh »

0x0 wrote: post #174
robomartin wrote: post #129

Earlier quoted context omitted.

...and it never occurred to you that a hypothetical is just a thinking tool rather than an absolute. OK, I'll play your game. The car would not turn on after being parked somewhere for four hours. Only an idiot software developer would brick it at high speed on the Autobahn.

That's what FTDI did though. They pushed the malicious bricking driver through an automatic Windows Update to systems already running in production, no? That's pretty much the equivalent of going at high speed on the Autobahn.

I really don't know how Windows' automatic upgrades work, but I would be baffled if an UART driver was updated on-the-fly while it's being used.

If I receive constant 1Mbps stream, the PLL doesn't even have time to stop/start? Or drivers are supposed to handle upgrade hand-off? Sounds crazy complicated, and I don't see the point of such a feature

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

#208

Post by varispeed »

lnsru wrote: post #189

Once I was working for a company having single Motorola 68K based design. They were selling their ancient design without changes for decades. Motorola 68K disappeared from market, they moved to Coldfire, but then peripheral chips got obsolete. It was a big problem. Junior boss started buying everything he could find in Chinese Internet stores. Everything was fake!!! Sometimes parts were empty shells, no silicon insid…

How is it even possible to sell products with these parts if you are unlikely going to get RoHS certificates? That's like asking to go bankrupt.

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

#210

Post by kire456 »

robomartin wrote: post #58
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…

> 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…

You are advocating willful destruction of property. Property that is neither yours nor FTDI's. This is illegal, and broadly considered bad taste.

A counterfeiter commiting crimes against FTDI does not excuse FTDI committing crimes against a third party (i.e. the consumer). The world being safer without the counterfeit products also does not excuse the FTDI destroying things that aren't theirs. The justice system being ineffective at addressing counterfeiters is also no excuse for FTDI to take matters into their own hands. Vigilante justice is usually illegal.

Programmers make mistakes. A bug in your counterfeit detection code may end up destroying legit products. In addition, you can not be sure destroying a product will be safe - if the chip is in a medical device, you might be killing someone. The entire idea of destroying a product without explicitly being told to do so is fraught with peril.

You deal in false binaries. The third, imo correct, option is for FTDI to design software that works correctly with their own product, and spend no effort on the counterfeits - neither to get them to work correctly, nor to brick them on purpose.

A fourth option, if you want to spend some effort on something other than destruction of property, is to take option three, and also alert the user that they are using a counterfeit chip with unpredictable behaviour, and in your airplane example, advise the user they should probably not take off. If you want to be pro-consumer, this is a better way to go about it than smashing their stuff.

From the consumer's perspective, they had a working device, and a firmware update bricked it on purpose. It is possibly out of warranty, in which case they end up footing the bill (or experiencing frustration) for replacement and downtime. It takes Olympic levels of mental gymnastics to view that as 'pro-consumer', imo.

Post reply on HN