This spring we are planning to include sensors that measure gas (ex. CO2, CH4, O3, CO) in the atmosphere. I was hoping to find something that we could use with RPi (through I2C or UART or an ADC) but we will go Arduino if we have to. I am concerned that the sensors I am looking at have temperature restrictions that are not cold enough, or that they require a minimum air pressure range not present at altitude. Does anyone have any experience with gas sensors on HAB flights with some suggestions or guidance for us?