DS18B20 waterproof from ebay VS original from local retailer

Have you ever wondered what this kind of ‘cheap’ temperature sensor is worth?


I wanted to set a dozen of these sensors up all over the house, so I first (quickly) compared these ready-to-use from China with the expected same oem chip (datasheet) from my local retailer.

This is not a benchmark at all, I just compared the measurements of  8 devices for 45 minutes inside and outside the house…

My conclusion is that at half the price (including delivery) for waterproof packaged and already wired sensors, I’m going for sure with the cheap ones 🙂

I’m quite confident in the ebay seller saying that the sensors are genuine as they work exactly in the same way that the ones from my local retailer… It’s not proof, I know…

I used this OneWire library (direct GitHub link) with this Dallas Temperature Control Library (direct GitHub link) and some clues from this page.

The library sample works just out of the box: connect as much sensors as you want (all on the same data pin) and the library will discover and get the temperatures…



As you could expect, the waterproof packaged ones react slower than the oem chips (much exposed to ambient air) but the measurements are very similar (<0.4 °C difference when stabilized).

Here is the link to the full log file (LibreOffice Writer sheet).



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