Error: dht22 read failed with status 2

[danio0701]

Can you help me figure out what is happening?

I have errors in homebridge [2019-3-3 21:30:01] [dht22] DHT Status: 2, Temperature: 0, Humidity: 0 [2019-3-3 21:30:01] [dht22] Error: dht22 read failed with status 2

Sometimes temperature is read correctly. I'm sure that DHT11 is working fine as from AdaFruit DHT is read correctly if I will check this sensor using this script. From your script I have correct reply only on 5% of request.

Next:

[2019-3-3 21:31:01] [dht22] Error: dht22 read failed with status 2 <-- this reply is more often, due that temperature is not displayed correctly in Home app. [2019-3-3 21:32:01] [dht22] DHT Status: 0, Temperature: 26, Humidity: 38

[danio0701]

Can you help me figure out what is happening?

I have errors in homebridge [2019-3-3 21:30:01] [dht22] DHT Status: 2, Temperature: 0, Humidity: 0 [2019-3-3 21:30:01] [dht22] Error: dht22 read failed with status 2

Sometimes temperature is read correctly. I'm sure that DHT11 is working fine as from AdaFruit DHT is read correctly if I will check this sensor using this script. From your script I have correct reply only on 5% of request.

Next:

[2019-3-3 21:31:01] [dht22] Error: dht22 read failed with status 2 <-- this reply is more often, due that temperature is not displayed correctly in Home app. [2019-3-3 21:32:01] [dht22] DHT Status: 0, Temperature: 26, Humidity: 38

Now I noticed also error: Error: dht22 read failed with status 3

If I will use dht22 command in terminal then output is: 3 0.0 C 0.0 % or 2 0.0 C 0.0 %

[NorthernMan54]

The plugin is just passing the errors it gets from the binary dht22. Try running it from the command line several times in a row, it should exhibit similar behaviour.

Do you have a wiring issue maybe?

On Mar 3, 2019, at 6:38 PM, danio0701 notifications@github.com wrote:

Can you help me figure out what is happening?

I have errors in homebridge [2019-3-3 21:30:01] [dht22] DHT Status: 2, Temperature: 0, Humidity: 0 [2019-3-3 21:30:01] [dht22] Error: dht22 read failed with status 2

Sometimes temperature is read correctly. I'm sure that DHT11 is working fine as from AdaFruit DHT is read correctly if I will check this sensor using this script. From your script I have correct reply only on 5% of request.

Next:

[2019-3-3 21:31:01] [dht22] Error: dht22 read failed with status 2 <-- this reply is more often, due that temperature is not displayed correctly in Home app. [2019-3-3 21:32:01] [dht22] DHT Status: 0, Temperature: 26, Humidity: 38

Now I noticed also error: Error: dht22 read failed with status 3

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[danio0701]

The plugin is just passing the errors it gets from the binary dht22. Try running it from the command line several times in a row, it should exhibit similar behavior. Do you have a wiring issue maybe? …

Do you have a wiring issue maybe? No, when I'm using Adafruit_Python_DHT then I always have temp and hum.

From terminal command DHT22:

2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 %

from AdafruitDHT (another solution I have this): pi@raspberrypi:~/Adafruit_Python_DHT/examples $ ./AdafruitDHT.py Temp=24.0* Humidity=33.0%

[NorthernMan54]

Sounds like the gpio pin configuration problem, the codebase assumes a connection to gpio 4. Where are you connected to?

Sent from my iPad

On Mar 3, 2019, at 6:48 PM, danio0701 notifications@github.com wrote:

The plugin is just passing the errors it gets from the binary dht22. Try running it from the command line several times in a row, it should exhibit similar behavior. Do you have a wiring issue maybe? …

Do you have a wiring issue maybe? No, when I'm using Adafruit_Python_DHT then I always have temp and hum.

From terminal command DHT22:

2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 %

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[danio0701]

I'm connected to gpio 4

Sometimes I got correct reply: 0 25.0 C 31.0 %

When I type command:

dht22 -g4 -i1 -m1 after 2 min of results 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % ...

I got this: 3 26.0 C 29.0 % 0 26.0 C 29.0 % 3 26.0 C 29.0 % 0 26.0 C 29.0 % 3 26.0 C 29.0 % 2 26.0 C 29.0 % 3 26.0 C 29.0 % 2 26.0 C 29.0 % 3 26.0 C 29.0 % 0 26.0 C 28.0 %

when I stopped command and start it again the result is: 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % 3 0.0 C 0.0 % 2 0.0 C 0.0 % ...

[NorthernMan54]

I’m not sure what is happening here as I’m using pigpiod to talk to the dht device and it seems to be having issues intermittently. The pigpiod library is here

http://abyz.me.uk/rpi/pigpio/index.html

I’m thinking it should be simple to switch to using the adafruit library instead, only problem is that I’m out of the country for a week and don’t have the ability to look at this in detail. The plugin just runs a command on the command line and parses the result from it.

Sent from my iPad

On Mar 4, 2019, at 3:39 AM, danio0701 notifications@github.com wrote:

I'm connected to gpio 4 (second pin on bottom)

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[danio0701]

I’m not sure what is happening here as I’m using pigpiod to talk to the dht device and it seems to be having issues intermittently. The pigpiod library is here http://abyz.me.uk/rpi/pigpio/index.html I’m thinking it should be simple to switch to using the adafruit library instead, only problem is that I’m out of the country for a week and don’t have the ability to look at this in detail. The plugin just runs a command on the command line and parses the result from it. …

Oki, thanks a lot for suggestions :) I'm new in this so I will try to read more how to switch these libraries.

[danio0701]

Is there source code of DHT22 file which I'm opening using command DHT22 and any instruction how to make from this code service again? I'm new in this stuff :P

[NorthernMan54]

Source is here

http://abyz.me.uk/rpi/pigpio/code/DHTXXD.zip

I did add a minor change to the source which is a patch in repo to include the Status and make the response easier to parse.

[danio0701]

I generated new DHTXXD, only changes I made in test_DHTXXD to select manually that I have DHT11. Now I have this:

pi@raspberrypi:~/DHTXXD-2 $ ./DHTXXD -i1 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 0 26.0 37.0 3 26.0 37.0 2 26.0 37.0 3 26.0 37.0 0 26.0 35.0 3 26.0 35.0 0 26.0 34.0 3 26.0 34.0 0 26.0 34.0 3 26.0 34.0 0 26.0 33.0 3 26.0 33.0 2 26.0 33.0 3 26.0 33.0 0 26.0 30.0 3 26.0 30.0 0 26.0 29.0 3 26.0 29.0 0 26.0 28.0 3 26.0 28.0 0 26.0 30.0 3 26.0 30.0

Correct read is a show until I stop reading from the sensor. When I start again command ./DHTXXD -1 then again few first reads will be:

2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0

Sometimes this will not work and reads only 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 3 0.0 0.0 2 0.0 0.0 ...

It's too difficult for me

[NorthernMan54]

What I was thinking was to change the parsing logic here

https://github.com/NorthernMan54/homebridge-dht/blob/dd0f61ac18399a41c5aa62fcab5ae8460c0e97a9/index.js#L85

To handle the response from the adafruit program, and ditch the dht22 binary going forward.

[danio0701]

Still I do not understand how to do that but I noticed that if I will add to config.json of homebridge:

{ "accessory": "Dht", "name": "Test-DHT", "service": "dht22", "dhtExec": "/home/pi/Adafruit_Python_DHT/examples/AdafruitDHT.py" }

Run homebridge then I have something like this:

DHT Status: Temp=25.0, Temperature: NaN, Humidity: NaN [2019-3-6 23:17:50] [Test-DHT] Error: dht22 read failed with status Temp=25.0 [2019-3-6 23:18:56] [Test-DHT] DHT Status: Temp=25.0, Temperature: NaN, Humidity: NaN [2019-3-6 23:18:56] [Test-DHT] Error: dht22 read failed with status Temp=25.0

Temperature is reading correctly. Humidity is not displayed in this error. I will try to change output, maybe then this will be work :)

[danio0701]

YES!!! It works! in homebridge config.json I add accessory:

{ "accessory": "Dht", "name": "Test-DHT", "service": "dht22", "dhtExec": "/home/pi/Adafruit_Python_DHT/examples/AdafruitDHT.py" }

and I changed code of AdafruitDHT.py output format and set this as defualt DHT11:

import sys

import Adafruit_DHT

humidity, temperature = Adafruit_DHT.read_retry(11, 4) if humidity is not None and temperature is not None: print('0 {0:0.1f} C {1:0.1f}%'.format(temperature, humidity)) else: print('Failed to get reading. Try again!') sys.exit(1)

[NorthernMan54]

Congrats

Sent from my iPad

On Mar 6, 2019, at 6:28 PM, danio0701 notifications@github.com wrote:

YES!!! It works! in homebridge config.json I add accessory:

{ "accessory": "Dht", "name": "Test-DHT", "service": "dht22", "dhtExec": "/home/pi/Adafruit_Python_DHT/examples/AdafruitDHT.py" }

and I changed code of AdafruitDHT.py output format and set this as defualt DHT11:

import sys

import Adafruit_DHT

humidity, temperature = Adafruit_DHT.read_retry(11, 4) if humidity is not None and temperature is not None: print('0 {0:0.1f} C {1:0.1f}%'.format(temperature, humidity)) else: print('Failed to get reading. Try again!') sys.exit(1)

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[danio0701]

Congrats …

Thank you for assistance and suggestions ;)

I noticed that sometimes is error in reading sensor - randomly. dhtExec function failed: Error: Command failed: /home/pi/Adafruit_Python_DHT/examples/AdafruitDHT.py -g 4

but its not visible in Home app and values are constantly updated :)