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Email Sensor

Summary​

Checks an email inbox for messages with a subject you choose. Handy for connecting Sentinel Circle to another alert system that sends emails — including a second Sentinel Circle phone.

Details​

How it works​

Sentinel Circle checks the inbox on a fixed schedule — every 30 seconds by default — looking at new messages in order, and alerts as soon as a check finds a matching one. There is no waiting or double-checking for email (unlike Wi-Fi and Bluetooth, this sensor never debounces; see Debounce), but the alert can still be up to one check interval behind the email arriving. Shortening the check interval shortens that gap.

Configuration​

Edit Email Trigger form showing the AWAY/HOME subject keyword fields

  • Unsafe Subject Filter — the subject word meaning "person left" (default: AWAY).
  • Safe Subject Filter — the subject word meaning "person returned" (default: HOME).
  • Check Interval — how often to check the inbox (default: every 30 seconds).
  • Mark as Read — automatically mark matched emails as read.

Tap Configure IMAP Server to enter the mailbox itself:

IMAP Server Settings dialog with host, port, username, and the App Password hint

  • IMAP Host — your email provider's incoming-mail server address (for Gmail: imap.gmail.com).
  • Port — usually 993 for a secure connection (default: 993).
  • Email / Username — the full email address for this mailbox.
  • Password / App Password — see below. For Gmail, this is not your normal Gmail password.
  • Use SSL/TLS — leave this on unless your provider tells you otherwise.

Use Test Connection before saving — it tells you right away if the server, username, or password is wrong, instead of finding out from a silently-failing sensor later.

Getting a Gmail App Password​

If the mailbox is a Gmail (or Google Workspace) account, typing the normal Gmail password will fail. Google requires a separate, 16-character App Password for apps like this one — it's not optional, and it's not the same thing as the password used to sign in to Gmail on a phone or in a browser.

  1. The Google account must have 2-Step Verification turned on first. If it isn't already, set it up at myaccount.google.com/security — App Passwords don't exist as an option until this is done.
  2. Go to myaccount.google.com/apppasswords and sign in again if asked.
  3. Type a name to remember it by — "Sentinel Circle" is fine — and select Create.
  4. Google shows a 16-character password in four groups of four letters (spaces don't matter). Copy it.
  5. Paste that — not the regular Gmail password — into the Password / App Password field above.

This same App Password also works for the Email channel's outgoing (SMTP) settings, if that's also a Gmail account.

Requires​

  • An internet connection.
  • A working email account, with an App Password if the mailbox is Gmail or Google Workspace.

Tip: The Email sensor is great for receiving alerts from a second Sentinel Circle phone. Set up Phone A to send emails on departure and return, and Phone B's Email sensor to watch for those emails. See the worked two-phone example.