My search for a PIR to HA (Home Assistant) work-out-of-the-box solution wasn't a success.

Since I am not having the necessary skills to write my own script, I decided to create my Frankenstein, using the code from two working scripts: https://github.com/R4scal/mhz19-mqtt-daemon (Most of the code comes from this) https://github.com/robmarkoski/pi-motion-mqtt-sensor Thank you very much @robmarkoski and @R4skal

This python script should work on any Rpi with a PIR connected to a GPIO and will create an entity in HA through MQTT Auto Discovery.

We need some py scripts to install first:

pip3 install paho-mqtt sdnotify colorama Unidecode

Clone the repository to your home directory

git clone https://github.com/Chreece/pir2ha
cd pir2ha

Check the values from config are ok with your installment

nano config.ini

If the values in config.ini aren't right for you, uncomment them and change only what needs to be changed (ctr+x to exit and save any changes).

Check if the service is right:

nano pir2ha.service

and then copy it to the system folder and start it:

sudo cp pir2ha.service /etc/systemd/system/

sudo systemctl daemon-reload
sudo systemctl enable pir2ha
sudo systemctl start pir2ha

After that a new binary_sensor entity should arrive in HA with the name from your host + "pir" (i.e. raspberrypi_pir). Since there is a device_class: motion it should already have the motion icon and you can also make changes in the UI because of the unique_id.

ENJOY!