A ros2 node that listens to teleop_twist message and publishes to mqtt topic pre-requisite is to install paho mqtt client like this:
pip install paho-mqtt
update configurations in following places
in ros2_mqtt/config/param.yaml file - replace 192.168.1.123 with ip address of where you are running mqtt broker [your computer]
in esp32/boot.py - update SSID and PWD for your wifi
in esp32/main.py - replace IP_ADDR_OF_MQTT_BROKER with your mqtt broker ip address [same as ####1]
build the project from root folder of workspace colcon build
launch the ros2mqtt node along with teleop twist nodes ros2 launch ros2_mqtt ros2_mqtt.launch.py
ros2 topic echo /cmd_vel
mosquitto_sub -v -t 'esp32/cmd_vel'
sudo systemctl stop snap.mosquitto.mosquitto.service
sudo systemctl start snap.mosquitto.mosquitto.service
install Thonny and set interpreter to esp32 connect esp32 via usb to your computer install esptool and flash micropython on esp32 upload boot.py and main.py files on esp32 and connect with esp32 again you should be able to send twist messages using joystick and should be able to confirm those messages are being published to mqtt topic by subscribing to mqtt topic and looking at the console log on Thonny where esp32 will log same messages