...a key press to switch it on and off, because I'm thinking I don't want to sit still throughout the entire flight? I may want to go for a coffee, or relax on the sofa while listening to the engines drone. In fact, I'm thinking that I may only want to use the TrackIR device for shooting a visual approach.I think I want get one, but close to AUD 300 is quite a price.Mike.

You can set a hotkey to freeze/unfreeze the motion capturing.

The TrackIR software sets the F9 key by default to pause the TrackIR unit, but it can be assigned to any key within the software.

Thanks for the info, guys.

No issue.