Always-on BLE wearable detection on iOS

Consumer Privacy

Industry: Consumer Privacy

Platform: iOS + BLE wearable

Stack: Swift · CoreBluetooth · CoreLocation · iBeacon · Twilio Voice

Description: iOS companion for a BLE wearable that survives weeks of background and dials emergency calls.

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The engineering surface was an iOS background-execution problem: generic BLE scanning does not survive the OS's aggressive suspension of idle apps, so the always-on detection workload had to ride iBeacon region monitoring, which is a first-class background capability. State signaling required encoding multiple distinct event types as transitions between independently-monitored regions. A second BLE layer covered pairing and firmware operations. Programmatic outbound calling — disallowed through the native dialer — required a VoIP path through a third-party voice SDK.

We owned the iOS client architecture, the iBeacon-as-always-on-carrier design, dual-role CoreBluetooth integration, and the call-initiation pipeline. The client owned the wearable firmware and the dispatch-side infrastructure.

Engagement: ~4-month build · single iOS specialist · 2023.

Engineering signal: reliable wake-and-fire across multi-week idle periods with the phone never foregrounded after initial pairing.