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Introduction to Sentinel Circle

Sentinel Circle is an Android app that helps you keep an eye on someone you care about — a parent or family member living with dementia or other declining cognitive function — without needing to watch over them constantly yourself.

You place a phone with Sentinel Circle running (or the person's own phone) so it can notice things like Wi-Fi and Bluetooth signals near home, incoming emails, or other notifications, and use them to tell whether the person is where they should be. When something changes — they leave the house, or a device that should always be nearby goes out of range — Sentinel Circle alerts the caregivers you've set up: a text message, a phone call, an email, an on-screen alarm, a sound, a vibration, or a WhatsApp message.

Sentinel Circle app icon

How it works, in three parts​

Sentinel Circle is built from three simple building blocks that you combine to fit your situation:

  1. Sensors watch a single condition relative to the phone Sentinel Circle runs on — for example, "is our home Wi-Fi network in range?" or "is Dad's smartwatch still nearby over Bluetooth?". A sensor is always in one of three states: it hasn't figured out yet, everything's fine, or something's wrong.
  2. Monitors combine one or more sensors into a single rule you care about — like "Mom is still home" — and decide when to raise or clear an alert based on those sensors.
  3. Channels are how you get told about it. There are seven: a text message, a phone call, an email, a WhatsApp message, a full-screen alert on the phone itself, a sound, and a vibration — you choose which ones, and to whom.

A note on experimental features​

Three of the pieces described in this manual — the Notification sensor, the Sentinel Area sensor and the WhatsApp channel — are still being refined, and Sentinel Circle hides them until you turn on Experimental Features in Application Settings. If one of them is missing from the list when you tap + to add a sensor or channel, that switch is why. Their pages say so too.

Who Sentinel Circle is for​

  • Family caregivers who want to know if a loved one with memory issues has left home unexpectedly.
  • Households that want a "digital fence" around a garage, medicine cabinet, or other restricted area, alerting when someone unrecognized is nearby.
  • Anyone who wants a second, automatic set of eyes that doesn't require watching a camera feed.

What's next​

The rest of this manual walks through setting up your first sensor, channel, and monitor, and explains what each alert means and how to respond to it.