DS18B20 probes

Do you have some experience with ds18b20 probes? Which type is really waterproof.

Have you ever use this one: http://elkys.cz/wp-content/uploads/2019/08/es-ds18b20_v1-00.pdf

or this one: https://www.dfrobot.com/product-689.html

Una pregunta

Tengo un sensor ds18b20 en un modulo en el cual ya viene incluida la resistencia, conecto y programo y el sensor costantemente me bota -127 °c

@JuanProxd Hello and welcome. You should read forum rules first. Do not hijack other's topic and use English please or write to international corner. There is also Spanish. Sorry I was hard on you.

@kyzi Depends on your need. I have no experience with these Chinese probes. However, at the first look they don't look really waterproof like for submerge. They are for splashing water max. In addition, they seem to be over prized. I do make probes for my applications by myself. Sensor is sealed with silicone in brass sleeve. With heat conduct paste of course; and small resistor, usually 75 -100 ohm, on data pin, next to the chip. Resistor is for reduction of reflections and noise for bigger bus.

The first tells you little and shows you nothing. It is just some panel bezel, so why would you trust somebody so incompetent, and can't spell "wrench"? The waterproofing ability is about the same as what you can expect from the second one, and the comment nay not apply to the bezel anyway.

The second one is about twice the price and with half the cable of what you can get on eBay. They are available with or without a 3-pin connector and cable up to 5m.They are just fine for testing in a glass of water but, if you need to get serious, it would make sense to slide back the cover and add some silicon goo. If you are really serious, you might consider a thermowell, but I have not seen a store-bought one specifically for DS18B20. I have also seen a screw-in pressure fitting DS18B20 - once. It's rarity was probably reflected in its price.

The ones I have bought and used are not water proof for extended use - often just sealed with a blob of silicon. I think they are really saying the tip is water proof , not the cable entry .
As suggested use a thermowell or make your own from a length of copper pipe with a sealed end and push one of these sensors down that .

I've seen the same thing I thing, prolonged use leads to failure. Silicone, not silicon (that would be waterproof!!)

One of the main reasons to enclose a temperature sensor in metal is to make it less sensitive to radiant heat so it can more accurately track the temperature of what it is clamped to. Errors of a degree or more are easily possible with a black epoxy heat sensor due to it absorbing radiant heat (far IR radiation). Most bare metals reflect heat radiation very efficiently.

MarkT:
Silicone, not silicon.

Oops

One of the main reasons to enclose a temperature sensor in metal is to make it less sensitive to
radiant heat so it can more accurately track the temperature of what it is clamped to. Errors of a
degree or more are easily possible with a black epoxy heat sensor due to it absorbing radiant
heat (far IR radiation). Most bare metals reflect heat radiation very efficiently.

I have made up a couple of thermowells but only one is in use. It did not seem to work any different from the sensor clamped to the pipe under insulation. This was over a range of 12>36C, but I don’t think that would be critical. Heat sink paste was used in both intances.

Thank you for your hints.
I got the first one type yesterday by mail. It looks like really waterproof - cable and sensor were sealed with polyurethane or silicone. I will test it with salt water up to 100°C.

es-ds18b20-back.jpg

es-ds18b20-front.jpg