Hello,
often my DHT sensor returns 00 01 93 ff ff ff ff ff ff with translates into NaN and NaN.
What is this value?
Hi @LuCavallin,
Just to be really certain, can you show us a list with the values you get?
Say … a screenshot of your terminal.
Coming back to your problem, the DHT
sensor is know for having lots of noise on its lines.
When a NaN
is read, this means there was noise down the line and the values couldn’t be read from the sensor.
For this issue I have a solution for you that I’ve developed a couple of weeks ago.
Here are 2 topics
that have as a subject the noise on the DHT
lines:
-
forum.dexterindustries.com/t/solved-dht-sensor-occasionally-returning-spurious-values
Here you’ll find a nice scenario with some really nice graphs and explanations. -
forum.dexterindustries.com/t/noise-removal-algorithm-for-grove-dht-pro-sensor/2989
Here is a more portable solution I’ve posted as a reply to the firsttopic
.
Nonetheless, you also have access to this solution from within our GrovePi
repository.
Here’s a link to the algorithm which helps reduce the noise between the DHT
and the GrovePi
:
Please try out some of those example programs and tell us how it goes.
If there’s anything else that needs our attention, please inform us.
Thank you!
Hi Robert,
I understood what the problem was - be ready, it’s rather stupid.
I was reading light and temperature concurrently
Hi @LuCavallin,
I’m glad everything solved out.
The GrovePi
library sometimes has some timing issues and because of this, I’d suggest you use locks
when developing multi-threaded
applications.
Thank you!
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