Hi Mark, thanks for replying!
I envisage a button press to calibrate the time if there is an internet connection and one to calibrate when facing North as per a magnetic compass. Not sure about accounting for magnetic declination.
I'm of the understanding that two of the hot shoe connections can be used as a simple button press, but I have not checked this. It would be nice to mount the Zero on the hot shoe to allow for grabbing the direction.
Apparently, geotagging for heading, tilt and range have been proposed by Flickr and described here:
I have no idea how to incorporate range, but general direction would suit me to start with!
As you have probably got most of your code "in your head", do you think it would be possible to parcel up the system into a callable routine?
Other ideas that I have might be to talk to my phone using bluetooth or wifi using this nifty add-on.
IO hat and perhaps use it as a backup (or primary) datalogger.