Temperature&Humidity Sensor Pro(DHT22) via ReSpeaker 2-Mics Pi HAT

Products & Technology Grove
#1

Hi guys

I am trying to get reading from the DHT22 Grove sensor via i2c port on the 2-Mics Pi HAT.

Can’t get any readings, can you please help?

It is connected to the i2c-1 port on the board.
I try every code I could and cannot get it to work.

the last code I tried was this:

both the Play With Raspberry Pi (With Grove Base Hat for Raspberry Pi) section

and Play With Raspberry Pi (with GrovePi_Plus)

and neither worked.

i2cdetect gives me this:

$ i2cdetect 1
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-1.
I will probe address range 0x03-0x77.
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- – -- – -- – -- UU – -- – -- –
20: – -- – -- – -- – -- – -- – -- – -- – --
30: – -- – -- – -- – -- – -- – -- – -- – --
40: – -- – -- – -- – -- – -- – -- – -- – --
50: – -- – -- – -- – -- – -- – -- – -- – --
60: – -- – -- – -- – -- – -- – -- – -- – --
70: – -- – -- – -- – --

#2

when i try this code:
git clone https://github.com/Seeed-Studio/Seeed_Python_DHT.git

I get this result:
$ python dht_simpleread.py

DHT22, humidity 0.0%, temperature 0.0*
DHT22, humidity 0.0%, temperature 0.0*

I wonder if i need to change this line to something else?

sensor = seeed_dht.DHT("22", 12)
#3

Are you connecting the Sensor GPIO12 grove connector ?

1 Like
#4

Hi @Tom_Zamir：
I would say, you connect DHT22 Grove sensor with the 2-Mics Pi HAT via GPIO12 port.

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image884×471 128 KB

1 Like
#5

Hi guys

So I thought it would go in the I2C port, like with the DHT31, but I tried the GPI12 port and indeed it works now with the code above.

but… I have very high error rate, most readings result in 0 temp and 0 humidity, and once in a while I get a good reading.

using this code base, any idea how I can improve this fault rate? I have 3 different zero pi and 2-mic hats and 3 sensors, and it happens with all of them .so i don’t think it is hardware specific.

not sure how to allow the sensor more time during sample with this dht_sensorsample.py

thanks in advance!

#6

You are right, changing to GPIO12 sort of works as I wrote in my other reply, it misses alot of readings

is there a way to connect it to I2C or do something about all the missed readings?

#7

You want to read the reading via I2C Protocol, or you want to use the pins?

#8

Hi Salman

Well currently it is not working well on the GPIO12 pins with this code:

before I used SEEED SHT31 with this code:

connected to I2C port, and it works like a charm

so I am trying to get the same stability/performance with the SHT22 humidity-temp pro sensor.

Any idea how to make this happen?

#9

well guys, i found that this script works just fine:

connecting the dht22/am2302 to GPIO12
and running:
sudo AdafruitDHT.py 2302 12

gives me accurate results every time… not sure why the Seeed library is failing in this instance…