Hi & welcome,
this kind of thing would typically be implemented in either of two ways:
- a separate/standalone program acting as a proxy between FlightGear and your hardware/telemetry
- directly modifying FlightGear by adding support for the required I/O protocols
The latter obviously requires being able to build from source, and knowing sufficient C++.
Regarding #1, you'll want to look at existing I/O means and see if/how they could be reused/adapted to be useful, see for example:
viewtopic.php?f=36&t=10173If this involves any form of USB devices that are currently not supported by FlightGear, there's also the pending USB/HID-support effort, see:
http://wiki.flightgear.org/USB_HID_SupportFor FlightGear as a project it would obviously be better to identify building blocks required to pull this off and then augment/extend the simulator accordingly.
On the other hand, a more modular approach may be easier to implement initially, especially for people new to FG, new to C++ - who may already have experience doing this sort of thing outside FG.
If you'd like to see additional suggestions posted, please provide some details on the hardware/transport mechanisms, protocols and message formats involved.