How to detect DHT22 Sensor disconnect, using UNO, and DHT library

Projects Programming
1

When my sensor has been disconnected, the value (a float) that gets sent via Serial.print(x) shows up in the serial monitor as "nan".
Where is this originated, and how can I intercept it and replace it with a different string like "Sensor x disconnected."?

2

Welcome to the forum.

Can you tell which sensor it is (if possible with a link to it) and which Arduino board you use, and which libraries you have used and show the sketch please.

Often a library can detect if a sensor has been disconnected. If not, then you can test for "nan" in the sketch or test for values that can't be true.

[ADDED]
I see now in the title that you have a Arduino Uno.
Could you scroll up and change the title, because the Serial response is not the problem. You could for example say "How to detect a disconnected NTC" if you have a NTC temperature sensor or "How does the OneWire library tell that a sensor is disconnected" if you would use the OneWire library.

3

Check with isnan().

But the sensor library begin() method probably returns a boolean for success or failure.

If you look at the library example sketches, you might find that they already do that.

4

Thanks everyone, the isnan() function did the trick!
Basically, I created a Boolean variable named skip1...n
h1 is the humidity data from sensor #1 (a float).

skip1 = isnan(h1);

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