Wemos D1 Mini and AZ Instrument 7798 CO2 Meter Datalogger
The AZ7798 CO2 Meter/Datalogger appears to be made by AZ Instrument, but other branded versions also exist.
The CO2 meter is already provided with a PC interface in the form of a logic-level (3V3) serial port, through a 2.5mm stereo jack on the back. The Wemos D1 Mini is connected to this serial port instead and the PC interface is no longer available.
The Wemos D1 mini is fitted inside the meter enclosure. This requires the enclosure to be opened. There are four screws. Two of the screws are hidden behind the type label. Use the point of a small knife to cut holes in the label. There are also two clips at the top of the enclosure. To release those, gently pry apart the bottom of the enclosure. The grey band between the two halves can now be lifted up and expose the clips at the top. A push with a flat-blade screwdriver will release the clip.