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Read-only pump reader

Android GlucoStride uses one pump reader and automatically shares its validated readings with the watch. It does not change therapy, calibration, pump time or settings, and does not retrieve glucose history.

Pairing and lifecycle

  • Grant Nearby devices and enable Bluetooth. The phone must support BLE peripheral advertising. Stop competing pump phone apps before pairing.
  • Choose Pair pump, then select Mobile Gluco through the pump's mobile-device pairing workflow. The pump connects to the phone; GlucoStride does not scan for pumps or require a manually entered serial or key.
  • Use Connect paired pump + watch for a saved pairing. Reconnect accepts only the saved pump address. Unresolved address changes may require deliberate re-pairing; unrelated peers are not trusted automatically.
  • Stop pump + watch closes both links. Forget local pairing removes only this app's metadata, not Android bonds or the pump's mobile-device pairing. Never remove the sensor/transmitter or reset all Bluetooth settings as a shortcut.
  • When changing phones, stop monitoring on the first phone and pair deliberately on the second. Do not copy pairing preferences or session keys.

One user-started connectedDevice foreground service renews a bounded wake lock. Ordinary saved-pump link loss retries with 5/10/15-second capped delays until stopped. Authentication failures and Bluetooth/permission loss require explicit recovery. Boot, process death and app updates do not restart monitoring. See background settings.

Watch advertising starts with saved-pair monitoring and sends unavailable during authentication. On first pairing it waits until the authenticated pump peer is saved. Pump and watch peer state, callbacks and subscriptions remain separate; watch failures retry after 30 seconds without restarting the pump.

Reading and source time

After SAKE authentication, the transport reads the CGM feature, session reference, sensor status and last measurement, then rechecks the session reference. Another poll runs about 15 seconds after the exchange completes; this is not the sensor's measurement cadence. Necessary writes are limited to authentication, notification subscriptions and the report-last-record request.

The parser checks frame structure, feature-dependent CRC, SFLOAT values and sensor status. Measurement time is session start plus measurement offset, not retrieval time. If session timezone/DST is absent, a read-only Current Time reference (0x1805/0x2A2B) compares the pump's local times without assuming the phone's timezone.

The bounded clock mapping stays fixed during monitoring. Invalid dates, missing/slow clock reads, inconsistent sessions, future samples and detected pump-clock jumps suppress values. A detected clock change latches a time error until restart. Without timezone metadata, mapped UTC is an estimate; after a monitoring restart it can shift by read uncertainty, and the watch may reject an older estimate until a newer sample arrives.

Accepted samples age using Android elapsed time. Repeated reads cannot make them younger. Values are hidden at source age 600 seconds, on read failure or disconnect, and after 90 seconds without a completed record. Current sensor status is checked even when an older stored record contains a number. Stopped/calibration-pending/calibration-not-allowed states are unavailable, not guessed to be warm-up. These thresholds are engineering limits, not clinical advice.

Diagnostics and compatibility

The app separates authentication, completed reads, reading validation and watch delivery. Completed records can be repeated or rejected samples; confirmed BLE sends can carry unavailable status and do not confirm watch rendering.

The optional Experimental discovery pacing: BALANCED setting is off by default and can be changed only while stopped. It requests link parameters after bonding; the pump may ignore or reject it. It does not change MTU or pump data.

The driver uses the reference CRC-16/CCITT-FALSE dialect and JavaSake clientCrypt() direction; it does not try alternate checksums or ciphers after failure. Unsolicited authenticated notifications advance the cipher but are not used as the requested record. Multiple records in one exchange are rejected. Android GATT attachment, device-information values and pump firmware compatibility require testing on actual devices, not just a successful build.

Privacy and licensing

Readings stay in memory and are cleared when monitoring stops. The phone blocks screenshots/recent-app previews while monitoring. Pairing addresses are encrypted with an Android Keystore AES-GCM key; backup/device transfer is disabled. Notifications and application logs exclude glucose and device identifiers.

The local watch link is unencrypted and unauthenticated. No internet permission, cloud endpoint or measurement database is used. Do not publish raw Bluetooth captures, pairing keys or health data. See third-party notices.