Showing a Google calendar on Lantern

Lantern can show any of your Google calendars on the wall display and in the app. It subscribes to the calendar’s secret address: the events stay in Google Calendar, where you add and change them, and Lantern shows a read-only copy that it refreshes every 15 minutes.

1. Copy the calendar’s secret address

You need a computer for this; the Google Calendar phone apps don’t have the setting.

1. Open Google Calendar in a browser and click Settings (the gear), then Settings.
2. Under Settings for my calendars on the left, click the calendar you want on Lantern, then Integrate calendar.
3. Find Secret address in iCal format and copy it.

The address starts with https://calendar.google.com/calendar/ical/ and ends in basic.ics. Anyone who has it can see the calendar’s events, so treat it like a password: Lantern stores it encrypted and never shows it again. Don’t use the Public address in iCal format of a private calendar; it only works for calendars you’ve made public.

No “Secret address” section? Your Google account belongs to a school or workplace whose administrator has turned off sharing calendars outside it. Ask them, or use a personal Google calendar.

2. Subscribe in Lantern

1. In the Lantern app, open Calendars under Settings in the sidebar (on a phone, open the sidebar with the menu button first).
2. Tap Subscribe to a calendar. Pasting a Google link chooses Google Calendar under Where is the calendar?, with these steps beside it.
3. Paste the address, give the calendar a name and a colour, and choose its usual members: the people its events belong to, so they show in their colour and in their column.
4. Tap Subscribe. Lantern checks the address straight away and tells you if it doesn’t work.

The calendar’s events appear at once, then update every 15 minutes; a change you make in Google Calendar reaches the feed within a few minutes. To update sooner, open the calendar in Settings > Calendars and tap Sync now.

If something goes wrong

Settings shows what happened under the calendar’s name:

• “Nothing is at that link: the secret address was reset, or the calendar was deleted.” Someone clicked Reset next to the secret address, which makes a new one and stops the old one. Copy the new address, unsubscribe, and subscribe with it.
• “Google refused that link.” You may have copied the public address of a private calendar; copy the secret address instead.
• “That Google link leads to a web page.” You copied the calendar’s web link; copy the Secret address in iCal format.
• “Lantern can’t reach that calendar’s server.” Check that the Lantern server can reach the internet.

To stop showing a calendar, open it in Settings > Calendars and tap Unsubscribe. Nothing changes in Google Calendar. If the address may have been seen by someone else, also click Reset in Google Calendar.

What Lantern shows

Titles, times, places, and notes (formatting such as bold text is dropped, and links show their address), including repeating events and their exceptions. Guests, video-call buttons, reminders, and attachments stay in Google Calendar. Events from a subscribed calendar can’t be changed in Lantern; change them in Google Calendar and they update on the next sync.