The Google App Script that allows you to send SMS notifications from Gmail without limits to the number of SMS that can be sent via Google Calendar in a given time period.
- Read this tutorial (https://developers.google.com/apps-script/articles/gmail_filter_sms);
- In step 7 section 1, copy and paste the script from Code.gs;
- Set a time-driven trigger to run the script every minute (https://developers.google.com/apps-script/understanding_triggers#TimeTriggers);
- Set the default time (9 minutes) to SMS reminder in your Google Calendar (http://www.youtube.com/watch?feature=player_detailpage&v=4z_mPT_OqwY#t=35s).