Hi, I read about your project and I’m very interest to participate in this project. I’m enjoy in the development of C++ projects, for Arduino Uno, ESP8266 and ESP32 programming with Arduino IDE.
I made a project based in the implementation of an Arduino Uno and an ESP8266 where the Arduino reads the data of a temperature sensor (dht22) and send it by UART to the ESP and then the ESP upload the information to an MQTT broker using Mosquitto, into specifics topics, posting the information in JSON format. Here I left some picture of the project. You can see this project made on my profile (https://www.freelancer.com/u/nico2747?w=f)
I hope with this proposal have fulfilled your expectations for this project, I and hope we can talk about this project. Thanks, and Regards!!