FileNotFoundError: (...) /usr/local/lib/python3.8/dist-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein

I am running Ubuntu Server 20.04 LTS 64-bit on a Raspberry Pi 3 B. I have a DHT11 sensor module.

I am following the instructions from https://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/python-setup but the code does not work for me.

I have successfully executed these commands beforehand:

sudo apt-get install libgpiod2
sudo pip3 install adafruit-circuitpython-dht

This is my code:

# ky015.py
import time
import board
import adafruit_dht

# Initial the dht device, with data pin connected to:
dhtDevice = adafruit_dht.DHT11(board.D3)

while True:
    try:
        # Print the values to the serial port
        temperature_c = dhtDevice.temperature
        temperature_f = temperature_c * (9 / 5) + 32
        humidity = dhtDevice.humidity
        print(
            "Temp: {:.1f} F / {:.1f} C    Humidity: {}% ".format(
                temperature_f, temperature_c, humidity
            )
        )

    except RuntimeError as error:
        # Errors happen fairly often, DHT's are hard to read, just keep going
        print(error.args[0])

    time.sleep(2.0)

This is the error I get:

ubuntu@ubuntu:~/ky015$ sudo python3 ky015.py
Traceback (most recent call last):
  File "ky015.py", line 6, in <module>
    dhtDevice = adafruit_dht.DHT11(board.D3)
  File "/usr/local/lib/python3.8/dist-packages/adafruit_dht.py", line 263, in __init__
    super().__init__(True, pin, 18000)
  File "/usr/local/lib/python3.8/dist-packages/adafruit_dht.py", line 69, in __init__
    self.pulse_in = PulseIn(self._pin, 81, True)
  File "/usr/local/lib/python3.8/dist-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/PulseIn.py", line 65, in __init__
    self._process = subprocess.Popen(cmd)
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/lib/python3.8/dist-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein'

I have also followed the instructions for “Setup your Linux Board for using CircuitPython Libraries”. The script blinkatest.py completes successfully (Link to code: https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi#blinka-test-3-15). Output:

ubuntu@ubuntu:~/ky015$ sudo python3 blinkatest.py
Hello blinka!
Digital IO ok!
I2C ok!
SPI ok!
done!

The file libgpiod_pulsein does exist. The Python code seems to try and run it with subprocess.Popen. That’s strange IMHO since the “lib” prefix does imply that it is a library, not an executable, right? On the other hand, a library should have a suffix of “.so”. I am dumbfounded by that file name. By the way, this is ldd output for the file:

ubuntu@ubuntu:/usr/local/lib/python3.8/dist-packages/adafruit_blinka/microcontroller/bcm283x/pulseio$ ldd libgpiod_pulsein
        not a dynamic executable

This is the stat output:

ubuntu@ubuntu:/usr/local/lib/python3.8/dist-packages/adafruit_blinka/microcontroller/bcm283x/pulseio$ stat libgpiod_pulsein
  File: libgpiod_pulsein
  Size: 19752           Blocks: 40         IO Block: 4096   regular file
Device: b302h/45826d    Inode: 391704      Links: 1
Access: (0755/-rwxr-xr-x)  Uid: (    0/    root)   Gid: (   50/   staff)
Access: 2020-05-05 10:00:24.194643069 +0000
Modify: 2020-05-05 10:00:10.230685234 +0000
Change: 2020-05-05 10:00:10.990682910 +0000
 Birth: -

I have tried to reinstall the packages, but it did not fix my problem.

[goldyfruit]

It seems to be related to 64-bits. I’m running Ubuntu 20.04 64-bits on my RPi 4B, and the libgpiod_pulsein library shipped with adrafruit_blinka Python package is 32-bits.

$ file ~/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein
/home/ubuntu/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0, BuildID[sha1]=356bb870cf3f5a35b0862d12a708b782a9c365f6, not stripped

So basically I had to recompile the library for arm64 architecture, here are the steps:

$ sudo apt install libgpiod-dev git build-essential
$ git clone https://github.com/adafruit/libgpiod_pulsein.git
$ cd libgpiod_pulsein/src
$ make
$ cp libgpiod_pulsein ~/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein

[c4explosive]

It seems to be related to 64-bits. I’m running Ubuntu 20.04 64-bits on my RPi 4B, and the libgpiod_pulsein library shipped with adrafruit_blinka Python package is 32-bits.

$ file ~/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein
/home/ubuntu/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0, BuildID[sha1]=356bb870cf3f5a35b0862d12a708b782a9c365f6, not stripped

So basically I had to recompile the library for arm64 architecture, here are the steps:

$ sudo apt install libgpiod-dev git build-essential
$ git clone https://github.com/adafruit/libgpiod_pulsein.git
$ cd libgpiod_pulsein/src
$ make
$ cp libgpiod_pulsein ~/.local/lib/python3.8/site-packages/adafruit_blinka/microcontroller/bcm283x/pulseio/libgpiod_pulsein

This works, thanks. Working on manjaro for raspberry PI 3B.