Sub-5 µA BLE sensor node with companion app

A North American consumer health company bringing a connected dosing device to market. They owned the industrial design and the clinical concept but had no electronics, firmware or app capability.

Power budget against connectivity. The device had to remain discoverable and log usage continuously while running for a week on a small internal cell.

Full-stack scope. Electronics, PCB, firmware, BLE profile, iOS app and Android app — one team accountable for the whole chain.

Dose integrity. Usage records had to survive power loss and out-of-range periods, then reconcile with the phone on reconnect without duplicates.

• Designed the board around a BLE SoC with aggressive sleep-state management, waking on sensor interrupt rather than polling.
• Trimmed idle current below 5 µA by auditing every leakage path: pull-up sizing, unused peripheral clock gating, regulator quiescent draw, level-shifter selection.
• Implemented flash-backed local event logging with sequence numbers, so records queue on-device during disconnection and reconcile idempotently on reconnect.
• Built a custom GATT profile for dose scheduling, cartridge identification and a child-safety lock state.
• Developed both mobile apps natively against a shared protocol specification, preventing behavioural drift between platforms.
• Power-efficient PCB layout: charge path separated from the RF section, antenna keep-out honoured, self-charging circuit isolated from sensing ground.

• Idle current held below 5 µA, meeting the runtime target
• Complete stack delivered by one team: schematic, PCB, firmware, BLE profile, iOS app, Android app
• Zero dose-record loss across disconnection testing
• Product shipped to market