December 10, 2024:
Here are two good pages about setting up MQTT and getting Publisher/broker and subscriber working.
https://bytebeam.io/blog/getting-started-with-mqtt-on-raspberry-pi-using-python/ - Probably better
as my Subscriber is written in Python. July 2023 Everything except how to set it up to start at boot.
https://diyi0t.com/microcontroller-to-raspberry-pi-wifi-mqtt-communication/
*** Excellent step-by-step setting up publisher, Broker and subscriber, except for autostart subscriber.
Now I need to find out how to get a python Subscriber to start at boot.
This link gives me the best help on what I want to do.
https://www.codementor.io/@ufuksfk/how-to-run-a-python-script-in-linux-with-systemd-1nh2x3hi0e
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Subscriber service now starts, but path to file is now
/home/peterm/pi/mqtt. The peterm is added because the Pi now needs a user and that is peterm.
14/12/24 Trying to get AP configured, but failing
https://themakermedic.com/posts/Pi-AP-Mode/ after configuring, tablet cannot find the SSID.
Will look at this one tomorrow:
https://www.raspberryconnect.com/projects/65-raspberrypi-hotspot-accesspoints/168-raspberry-pi-hotspot-access-point-dhcpcd-method
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Alternatively using crontab:
https://tutorials-raspberrypi.com/control-raspberry-pi-robots-via-infrared-remote-control-part-3/
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Here is the earlier post about it.
https://www.blogger.com/blog/post/edit/preview/5415560036905179298/8810457589872963960
GPIO PIN Wire colour
Car Test Rig
6 White Pale yellow
12 Orange White
18 Red Blue
19 Yellow Orange
23 Green Yellow
Now I can swap R-Pis and see if there is a problem with the car one.
swapped boards, and test rig ran the same, except that after analog left, left LED kept flickering and I couldn't stop it. Another software fault.
Also Red forward LED on at startup.
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23/8/2024
HAve rebuilt software using latest RaspIOS and it is different.
Looking at this to try and figure out how to configure it.
https://bytebeam.io/blog/getting-started-with-mqtt-on-raspberry-pi-using-python/
Problem installing Paho-mqtt. Need to look into it.
12/10/24 working through this. Got through the update of Setting up Python dependencies and installing MQTT Python Libraries
NOW! I remember, On boot I have to start the subscriber program. I'll look in a previous writeup and see if I described the process.
This goes quickly but gives instructions on how to enable the subscriber. and set the broker to run in the background.
https://www.youtube.com/watch?v=za-IIZ1xVbA
22/10/24 https://forums.raspberrypi.com/viewtopic.php?t=318784 this gives some good advice for simplifying subscriber.
23/11/24 Useful commands https://linuxhandbook.com/systemctl-commands/
https://randomnerdtutorials.com/how-to-install-mosquitto-broker-on-raspberry-pi/
https://randomnerdtutorials.com/testing-mosquitto-broker-and-client-on-raspbbery-pi/
https://pimylifeup.com/raspberry-pi-mosquitto-mqtt-server/
https://tutorials-raspberrypi.com/raspberry-pi-mqtt-broker-client-wireless-communication/?utm_content=cmp-true [ this one needs some editing and explanations.]
What I am missing is "sudo python mqtt_subscriber.py" and what I need is to know how to enable this in startup.
Useful from Pimylifeup: sudo systemctl status mosquitto
Starting subscriber at login:
https://linustechtips.com/topic/1465144-run-python-scripts-on-startup/
Few ways,
Create a bat file and put it in the startup folder. The bat file would look something similar to this
python3 [path to run]Or however you run a python script on your computer in command prompt. Confirm that it runs your python script and then put in your startup folder and it will run at login.
Other options, go to task scheduler.
Create a new task
Add a new trigger; selecting on startup (I can't remember you might need to click the run even if user isn't logged in...can't remember exactly when that triggers). You could also do on login
EVEN Better:
https://www.howtogeek.com/687970/how-to-run-a-linux-program-at-startup-with-systemd/
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starting from scratch.
2025-1-4 image imaged onto 16Gb card. Set the userID and wifi parameters.
Fing shows RPi at 192.168.1.26
Had to change keygen, but then able to login via ssh.
sudo raspi-config to expand filessystem, and reboot.
sudo apt update,
sudo apt-get install firmware-zd1211.
and nmtui to configure Ethernet IP and Wifi
Ethernet 192.168.1.9/ 24 GW=192.168.1.31
Wifi rc-car Ashmeads Access Point 192.168.4.1/32 GW 192.168.4.255
sudo reboot
on ip .9 - good
check ifconfig
OK.
Now see above to set up MQTT
https://diyi0t.com/microcontroller-to-raspberry-pi-wifi-mqtt-communication/
See Broker setup
Installation doesn't like reference to Raspian.
Looks like it needs a DNA specified in IP config. Back to nmtui. No effect.
Found
https://stevessmarthomeguide.com/install-mosquitto-raspberry-pi/
Which includes some setup that the others haven't even if it has not been updated for Raspbios 'Bookworm'.
But problem here too:
Resolving repo.mosquitto.org (repo.mosquitto.org)... failed: Temporary failure in name resolution.
wget: unable to resolve host address ‘repo.mosquitto.org’
None of the solutions seem to work because
sudo systemctl status systemd-resolved.service could not be found.
More work needed here: Tomorrow.
