I love the idea of helping people living in rural areas
Make a plugin with the API
https://github.com/meshtastic/Meshtastic-device/blob/master/docs/software/plugin-api.md
Regarding the hardware, you could use an esp32 board, a lora radio and the sensor… (they sell some without display) I was thinking about an oled display but this one won’t be necessary ^^ ah and also a solar panel .
If you want you could post the text in a pastebin? Or right here
You could also check this post
And maybe @luandro could help you
Good luck