Watcherr - Connected Safety Platform
Product lifecycle for a regulated care-home IoT device, from PRD to validation.
Risk Assessment Iterations
Assessed in Final Matrix
Roadmap Horizon
Tools & Methods
The problem
An elderly care resident wears a wristband 24 hours a day. If they press the alarm button and nothing happens, that's not just a product bug - it's a safety incident that could cost a life. At the same time, the device has to be simple enough that non-technical care staff can set it up and use it every day without training.
The challenge
Watcherr operated in care homes where the wristband was worn 24/7 by elderly residents and triggered distress alarms for caregivers. The product had to meet a dual constraint: robust enough for a regulated safety context (missed alarms = patient safety events) while simple enough for non-technical care staff to install, maintain, and use. Product decisions - feature scope, release sequencing, risk prioritisation - had to balance caregiver workflow needs, hardware capability limits, regulatory exposure, and a small engineering team with finite capacity. The V1 product spec had to be precise enough to drive firmware and app development while leaving room for field learning.
Product Requirements Document
PRODUCT REQUIREMENTS DOCUMENT
Watcherr V1 - Care-Home Safety Wearable
Varun Cumbanungam · Product Owner · Watcherr / ixicare (2022-2024)
Doc ID
WTR-PRD-V1
Status
Approved
Owner
Varun C.
Date
Q3 2024
Version
2.0
Problem Statement
Care homes need guaranteed alarm delivery for a regulated patient-safety context while remaining simple for non-technical staff operating 24/7.
Primary Users
Resident Wearer
Raise distress alarm, fall protection, activity log
Caregiver Responder
Real-time alarm + location, acknowledge flow
Facility Admin
Device provisioning, fleet overview
Field Installer
BLE pair, OTA update, gateway setup
Core Use Cases
- Manual alarm - button press → caregiver notification <3s
- Geo-fence breach - resident exits zone, GPS-triggered alert
- Fall detection - accelerometer drop pattern → auto alarm
- OTA firmware - BLE chunk delivery, dual-bank Nordic DFU
Key Acceptance Criteria
- AC-1Alarm delivered to gateway within 500ms of trigger
- AC-2Out of range: retry every 10s for 5 min
- AC-3Alarm visible in app within 3s of gateway receipt
- AC-4Alarm persists until acknowledged by authorised user
- AC-5LED red blink + vibration confirm alarm active
- AC-6OTA completes without interrupting alarm monitoring
Risk Assessment (ISO 14971)
- HIGH
Missed alarm - patient safety event
Sticky-msg retry + geofence backup
- HIGH
Gateway out of range - undelivered
Flash-buffer offline, 5-min retry
- MED
OTA brick - device offline
Dual-bank DFU, abort-to-alarm fallback
- LOW
BLE pairing failure at site
NFC fallback + installer QR flow
Product Artefacts Delivered
- PRD V1 - personas, use cases, acceptance criteria
- Product Spec V1 - hardware + firmware requirements
- Risk Assessment V1 (23 risks) + V2 (31 risks, post-field)
- Q3 2024 Roadmap + Watcherr Pro Validation
CONFIDENTIAL · Watcherr V1 PRD · Property of Watcherr / ixicare
PRD · Product Spec · Risk Assessment V1+V2 · Q3 2024 Roadmap
Full PRD and supporting artefacts available upon request
Results
The V1 PRD and Product Specification drove the initial firmware and Android app build, shipping to the first care-home pilots in Belgium. The Risk Assessment V1→V2 evolution tracked 8 additional risk scenarios surfaced from field deployments, with mitigations mapped to firmware changes (sticky-message guarantee for alarm delivery, geofence breach on gateway loss). The Q3 2024 Roadmap was presented to company stakeholders and shaped the final engineering backlog before Watcherr rebranded as ixicare. The Watcherr Pro Validation presentation demonstrated conformance of shipped hardware against the original product spec to external partners.
Gallery & Demos
Alert Workflow - Caregiver Notification
Step-by-step visualization of how a resident's alert reaches the care staff smartphone in real time.
System Architecture - How It Works
Diagram explaining the complete workflow: device → gateway → cloud → mobile app alert delivery.
Mobile App Interface
Caregiver mobile app showing active devices, alert history, and quick acknowledge buttons for urgent requests.
Click any image or video to expand · ← → keys navigate
On-Device Activity Recognition - Care Wristband
On-device caregiver activity classification for a Nordic nRF52 wristband, covering IMU data collection, Edge Impulse training, TFLite Micro firmware, and a BLE activity viewer. It runs in 64 KB of RAM without a cloud round-trip.
Hardware & Firmware QA - IoT Wearable Platform
QA lead for the full Watcherr device family - owned test planning, structured firmware release gating, battery life validation, and risk assessment across Watcherr Lite (B7/B8), Watcherr Pro, and the G1 Gateway. 23 test reports spanning 10+ firmware versions, 344+ test cases passed with a 97.4% pass rate.
BLE Wearable System Architecture & Protocol Design
Contributed to the system architecture and protocol design for the Watcherr IoT wearable platform: 7 custom communication protocols (BLE packet definition, OTA DFU trigger, alarm state machine, RPC, WebSocket, sticky notification, sticky message), fail-safe system design, and software state-loop architecture spanning device, gateway, and cloud.
Interested in this work?
I can walk through the architecture and code during an interview.