Unreleased FW v1.3.0 - receiving only 0.0 values from DHT Pro sensor

grovepi
dht
pending
fw130
#1

Hello,

on my GrovePi board i’am using a DHT Pro sensor, the high accuracy I2C barometric sensor, a temperature sensor and a moisture sensor on analog ports, an I2C relay board and some digital input/ouput modules.

I read in the forum a few threads that the sensor values are messing up sometimes when using DHT and analog sensors together.
I have exactly the same problems. When i add a time.sleep after each read of a sensor value it is getting better, but at least after about 5 minutes, the analog temperature value is not updated anymore and returns from now on always the same value.

I have seen the thread with the new firmware release and read that the new firmware should solve the problems.

So I installed the new firmware 1.3.0 to test if things are getting better.
But now ,with the new firmware the DHT sensor returns only 0.0 values for temperature and humidity.
But at least it looks like, that the mess up on analog ports is gone, so values from analog sensors
seems to be fine over a long time.

#2

Hi @marc,

I don’t have a DHT Pro around to test with, so do you have a blue DHT sensor instead?

Generally, if you’re receiving zeroes then it either means the sensor doesn’t work (which is unlikely) or that there’s a module mismatch between what you have and what the firmware expects.

Can you try reading only the DHT sensor, so that we can rule out any problems with the firmware, should they exist?
And also, can you use all model numbers for the DHT sensor? More can be seen here in the documentation:
https://robertlucian.github.io/GrovePi/api/general/#grovepidhtpin-module_type

Thank you!

#3

Hello @RobertLucian,

i only have a DHT Pro sensor (the white one) . So it’s not possible for me to test with the blue one.

When i first installed the firmware 1.3.0 nothing was working at all, but then i’v seen that my programs are using the old grovepi.py 1.2.7 libs from folder
/home/pi/Desktop/GrovePi/Software/Python. Then i changed this, to use the libraries from /home/pi/Dexter/GrovePi/Software/Python and the grovepi was working again.
But i got only 0.0 values from DHT.

After that i reinstalled the 1.2.7 firmware to check i was breaking the DHT maybe because of the library mess up.

And with 1.2.7 the DHT was working again. So i think this could be a bug in the new firmware, but i’m not sure, because maybe there was still some problems with the libraries.

Is it somehow possible, to remove all the grovepi stuff from the raspberry pi and make a fresh installation of it with firmware 1.3.0 to test it again?

#4

Hi @marc,

You can start with a fresh Raspbian that has absolutely nothing related to the GrovePi installed on it and use the instructions provided in the Getting Started section of this following thread (you already know it):

And then follow the instructions on the documentation so that you can flash the firmware onto it.

Now, regarding the DHT Pro sensor, I already have placed an order for it and I should be receiving the package really soon. And when I get it, I can start testing it.

Let me know how it goes for you.

Thank you!

#5

Hi,

i did one more test with a fresh installation. First with Firmware 1.2.7, and DHT was running perfect.
Then updated to 1.3.0 and dht returns only 0.0 values.
I also tried tu use the different types, but for all types (0-3) it returns 0.0 values.
Sensor is connected to D2.
I used the example python programm from GroviPi Software folder. So no other sensors or modules was connected and read out.
So i guess it is a bug in the firmware.

#6

Hi @marc,

So it seems. The moment I receive the package, I’ll start doing tests and see where the issue comes from.

Thank you!