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Topic: Urgent, I need an advice regarding hygrometre sensors (Read 275 times) previous topic - next topic

TommasoPraturlon

Hello everyone!

I've bought five hygrometres TE-215 from China and I tested one of them to read the humidity of the soil in a vase, yet, after few days in it, the metal part of the hygrometre set underground became oxidized, I guess it shouldn't, right? Due to that I can't use it anymore but I have four left.

I have two options: buy a chemical product to prevent the oxidation and spray it on the hygrometre's surface (though I think that it will compromise the data values read) or buy a new higher quality hygrometre from Arduino store (will it be damaged in the same way?).

What do you reckon as the best option?

Thank you in advance.

Tom

ted


use not rusting materials, stainless rods,galvanised nails, brass ...
Hello everyone!

read the humidity of the soil in a vase,



Tom

Actually you are measuring resistance between two points at specified distance,  use non rusting materials, stainless rods, galvanised nails, brass ...

DrAzzy

This is always a problem with those cheap soil humidity sensors, the design is fundamentally flawed; maybe with the hard gold surface treatment (I don't think ENIG is good enough) it could work, but not with exposed copper, tin, or similar. Those cheap boards from china just are not fit for purpose; they should not be used.
You can improve things a little by alternating the polarity you apply to the electrodes in the soil, and by only running it briefly, but those just slow the inevitable. Oh - and they contaminate the soil with dissolved copper...

There are more expensive capacitive sensors that don't rely on the conductivity of the soil; these don't have the problem of electrochemically dissolving themselves in the soil.
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