I plan to design a quadcopter as my final project, and use Navio2 as a flight controller. In the quadcopter that I designed, I will include the MQ-7 gas sensor to detect carbon monoxide levels, and MG-811 to detect carbon dioxide levels.
I have a follow-up question, when Raspberry pi 3 B + is already accompanied by Navio2 as a flight controller, can Raspberry pi 3 B + still be a processor to process the data from the two sensors I included earlier?
Can’t see any issue with using RPi as computer to process data from your sensors. By the way, have you checked RPi4? It’s more powerful and perhaps will suit better for your purposes.
This would actually be the perfect use case scenario for the Navio2 as your flight controller compared to a stand-alone Pixhawk or similar FC. There will be plenty of CPU cycles left to poll the sensors and record the data with Arducopter running in the background. I second @dmitriy.ershov with the suggestion for the Pi 4. Unless you already have a Pi 3 B+ to try, the money would be better spent on the 4, as it’s noticeably faster.