Changing 'SyncValue' time from Opals to Matlab time.

To change the values given by the 'SyncValue' field of the Opals to be in the same format as Matlab uses for time:

opal_sync_value = whatever you got from the Opal
opal_sync_to_seconds = 2560
seconds_per_day = 86400

matlab_time = ((opal_sync_value/opal_sync_to_seconds)/ seconds_per_day) + datenum(1970, 1, 1, 0, 0, 0);

As matlab's time values are expressed in days from the year 0, Jan 1st and the Opals record time in 1/2560s from Jan 1, 1970.

(Thanks to Tom Davies for this post)