Counterfeit DS18B20 temperature sensors

[Andreas]

Chris Petrich has a nice report about counterfeit DS18B20 temperature sensors along with test programs how to detect them. Use them at your own risk.

Introduction

We bought over 1000 “waterproof” probes or bare chips from more than 70 different vendors on ebay, AliExpress, and online stores -big and small- in 2019. All of the probes bought on ebay and AliExpress contained counterfeit DS18B20 sensors, and almost all sensors bought on those two sites were counterfeit.

TLDR; How do I know?

If the ROM does not follow the pattern 28-xx-xx-xx-xx-00-00-xx, then the DS18B20 sensor is a clone.

Also, there are two Arduino sketches provided to test DS18B20 sensors:

• discover_fake_DS18B20.ino performs some harmless tests and indicates if they show deviations from authentic DS18B20. Not designed to work with parasitic power.
• classify_fake_DS18B20.ino is a minimal implementation matching a sensor to a specific family [of clones] based on the response to undocumented function codes. Output is specific but rather boring. Use at your own risk.

GitHub - cpetrich/counterfeit_DS18B20: How to tell original from fake DS18B20...

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This has already been mentioned at

• Why use so many interior temperature sensors in just one hive? - #8 by weef ,
• Untersuchung und Verbesserung des Timings bei der Ansteuerung der DS18B20 Sensoren unter MicroPython - #114 by wtf and
• Info: Deep Sleep Stromverbrauch DS18B20.

[weef]

Eine weitere Testanordnung, um gefälschte DS18B20 herauszufinden:

electrical-pro/Ds_Fake_Tester

[weef]

Acht mal Klon-Familie D2 (“noisy rubbish”) - und einer davon ist noch schlechter und kann nur 0,5°-Schritte (angebliche Zwischenschritte lediglich durch display-interpolation im Grafana):

[weef]

Deeper insights of how the 18B20 clones look inside, who makes them, how they do perform:

https://www.tinytransistors.net/2021/01/16/real-vs-fake-ds18b20/

https://www.tinytransistors.net/2021/02/21/second-source-18b20s/