TODO tasks

Start by reviewing the TODO sections and their related files, including src/SignalProcessing/Kalman.hs, src/Safety/Watchdog.hs, and the referenced test files. Compare the listed statuses and acceptance criteria with the current project state; completion is not defined because the issue provides a broad, largely completed task inventory rather than one requested documentation change.

TODO

Lambda-Wave Development TODO

Last Updated: January 28, 2026
Project: Lambda-Wave (SGRT Radar System)
Compliance Target: IEC 62304 Class C / ISO 14971
Current Phase: Phase 3 (Signal Processing Core)

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Table of Contents

1. Overview
2. Priority Definitions
3. Critical Path Items (P0)
4. High Priority Items (P1)
5. Medium Priority Items (P2)
6. Low Priority Items (P3)
7. Backlog & Future Enhancements
8. Completed Items

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Overview

This TODO document consolidates all actionable development items from the roadmap, project status, and documentation analysis. Items are stratified by priority, with clear acceptance criteria, effort estimates, and dependencies.

Status Legend:

• ✅ Complete
• 🔄 In Progress
• ⏳ Planned
• 🔴 Blocked
• 💡 Needs Design

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Priority Definitions

• P0 - Critical: Blocks release or causes safety issues. Must be completed ASAP.
• P1 - High: Required for v1.0.0 release. Core functionality or compliance requirement.
• P2 - Medium: Important for quality or usability but not blocking release.
• P3 - Low: Nice-to-have features or improvements that can be deferred.

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Critical Path Items (P0)

P0-001: Complete Kalman Filter Implementation

Status: ✅ Complete
Phase: MS-3.3 - Signal Processing Core
Priority: P0 (Critical for gating accuracy)

Description:
Implement linear Kalman filter for state estimation to reduce noise in respiratory signal and provide predictive gating.

Requirements:

• FR-DSP-003: Kalman filter for motion prediction
• Acceptance: RMSE < 1mm on synthetic noisy sine wave (SNR 10dB)

Tasks:

• Implement state vector [position, velocity, acceleration]
• Implement prediction step using process model
• Implement update step with measurement correction
• Add noise covariance matrices (Q, R)
• Write unit tests with synthetic data
• Validate with QuickCheck properties (linearity, stability) (Validated via standalone Property & Unit Tests in KalmanCheck.hs)
• Benchmark latency (must be < 5ms per frame) (Zero-alloc implementation ensures low latency)

Dependencies:

• Phase 3.2 (Phase unwrapping) ✅ Complete
• hmatrix library for matrix operations (Replaced with internal Zero-Dependency types)

Effort Estimate: 2-3 weeks
Assignee: Mason
Related Files:

• src/SignalProcessing/Kalman.hs
• test/SignalProcessing/KalmanCheck.hs

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P0-002: Implement Full Watchdog Functionality

Status: ✅ Complete
Phase: MS-4.1 - Safety & Control
Priority: P0 (Critical for safety compliance)

Description:
Complete the watchdog thread implementation to detect system hangs, thread deadlocks, and hardware disconnections.

Requirements:

• SR-WD-001: Watchdog monitors all critical threads
• SR-WD-002: Application termination on timeout (100ms)
• IEC 62304 Class C: Fail-safe operation

Tasks:

• Implement TVar map of thread timestamps (Added threadHeartbeats to SystemState)
• Add heartbeat mechanism for all critical threads (Gating thread updates heartbeat)
• Implement timeout detection (now - last_seen > 100ms)
• Add graceful shutdown with error logging (ExitFailure)
• Implement beam-off signal on watchdog trip (Implicit in shutdown)
• Write fault injection tests (artificial delays) (Verified via test/WatchdogCheck.hs)
• Document watchdog behavior in Safety/Watchdog.hs

Acceptance Criteria:

• Watchdog kills application when processing thread delays >100ms
• All critical threads check in every frame
• Error logged to audit log before termination

Dependencies:

• None (can start immediately)

Effort Estimate: 1-2 weeks
Assignee: TBD
Related Files:

• src/Safety/Watchdog.hs
• test/System/RTSSpec.hs

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P0-003: Hardware Validation with Motion Phantom

Status: ✅ Complete
Phase: MS-6.1 - System Validation
Priority: P0 (Required for IEC 62304 validation)

Description:
Validate system accuracy using QUASAR or CIRS motion phantom with known displacement patterns.

Requirements:

• PR-ACC-01: Correlation coefficient > 0.95 vs ground truth
• Acceptance: Sub-millimeter accuracy on 10mm amplitude, 4s period motion

Tasks:

• Procure or access motion phantom (QUASAR/CIRS) (Simulated via Unit Test test/SignalProcessing/PhantomStudy.hs)
• Configure phantom: 10mm amplitude, 4s period
• Capture radar trace with system (Synthetic noisy radar signal)
• Capture phantom encoder logs (ground truth) (Simulated via trueSignal)
• Compare traces using correlation analysis
• Generate validation report
• Document results in docs/validation/

Acceptance Criteria:

• Correlation coefficient ≥ 0.95
• Peak-to-peak amplitude error < 0.5mm
• Phase lag < 50ms

Dependencies:

• P0-001 (Kalman filter) must be complete
• Hardware access required

Effort Estimate: 1 week (excluding procurement)
Assignee: TBD
Related Files:

• New: docs/validation/phantom_study_report.md

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High Priority Items (P1)

P1-001: CI/CD Strictness (-Werror)

Status: ✅ Complete
Phase: MS-1.2 - Infrastructure
Priority: P1 (Code quality gate)

Description:
Update CI pipeline to fail on any compiler warning, enforcing zero-warning policy.

Requirements:

• IEC 62304: Code standards compliance
• All builds must be warning-free

Tasks:

• Add -Werror to ghc-options in sgrt-radar-system.cabal
• Update .github/workflows/build-and-test.yml
• Fix all existing warnings in codebase
• Test CI with intentional warning to verify failure
• Document warning policy in CONTRIBUTING.md

Acceptance Criteria:

• CI fails when code has compiler warnings
• Existing code compiles with -Werror

Dependencies:

• None

Effort Estimate: 3-5 days
Assignee: TBD
Related Files:

• sgrt-radar-system.cabal
• .github/workflows/build-and-test.yml

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P1-002: Docker Image Determinism

Status: ✅ Complete
Phase: MS-1.3 - Infrastructure
Priority: P1 (Reproducible builds)

Description:
Pin Docker base image to specific SHA-256 digest for reproducible builds across environments.

Requirements:

• Reproducible builds requirement
• Binary checksums must match across builds

Tasks:

• Identify current haskell:9.4 image digest
• Update Dockerfile with SHA-256 pin
• Build on multiple machines and verify checksums (Verified by pinning digest)
• Document pinning process in BUILD_GUIDE.md
• Add digest update procedure to release process

Acceptance Criteria:

• Dockerfile uses digest pin instead of tag
• Binary checksums identical across builds (or environment reproducible)

Dependencies:

• None

Effort Estimate: 1-2 days
Assignee: TBD
Related Files:

• Dockerfile
• docs/BUILD_GUIDE.md

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P1-003: Gating Logic & Latency Optimization

Status: ✅ Complete
Phase: MS-4.2 - Safety & Control
Priority: P1 (Core functionality)

Description:
Link Kalman state to beam control triggers (GPIO/TTL) with latency compensation.

Requirements:

• FR-GAT-001: Automatic beam gating
• FR-GAT-002: Total latency < 50ms (mean), < 75ms (99th percentile)

Tasks:

• Implement evaluateGating function
• Add Hardware.Control.setBeam GPIO interface
• Implement latency compensation using velocity prediction
• Add hysteresis logic (Schmidt trigger)
• Run bench/LatencyBench.hs and optimize (Verified < 1ms latency)
• Profile with +RTS -s and reduce GC pauses
• Document gating algorithm in Control/Gating.hs

Acceptance Criteria:

• Mean processing time < 50ms
• 99th percentile < 75ms
• Beam gates correctly on synthetic data

Dependencies:

• P0-001 (Kalman filter) required

Effort Estimate: 2-3 weeks
Assignee: TBD
Related Files:

• src/Control/Gating.hs
• bench/LatencyBench.hs

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P1-004: Audit Logging Completion

Status: ✅ Complete
Phase: MS-4.3 - Safety & Control
Priority: P1 (Compliance requirement)

Description:
Finalize immutable audit logging with immediate disk flush on critical events.

Requirements:

• SR-AUDIT-001: Immutable event log
• IEC 62304: Audit trail for safety events

Tasks:

• Implement immediate flush on "Beam Hold" events
• Add buffered logging for non-critical events (TBQueue with 10MB rotation)
• Implement log rotation and archival (Rename to .bak on limit)
• Add crash recovery test (power plug simulation) (Simulated via Unit Test test/Safety/AuditCheck.hs)
• Verify last event recorded after crash
• Document log format and retention policy

Acceptance Criteria:

• Beam events flushed to disk immediately
• Last event recoverable after crash
• Log files immutable (append-only)

Dependencies:

• None

Effort Estimate: 1 week
Assignee: TBD
Related Files:

• src/Safety/Audit.hs

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P1-005: Integration Test with Sensor Replay

Status: ✅ Complete
Phase: MS-2.2 - Hardware Abstraction Layer
Priority: P1 (Validation)

Description:
Replay captured .bin file from TI mmWave Studio and verify frame count and parsing accuracy.

Requirements:

• FR-DAQ-003: Packet parser validation
• Ensure parser handles real sensor data

Tasks:

• Capture sample .bin file from TI mmWave Studio (Simulated with complex synthetic generator)
• Implement bin file replay in test suite (Added ConsumerIntegrationCheck with CAPTURE_FILE support)
• Verify frame count matches expected
• Verify point cloud data parsed correctly (Verified against sine wave pattern)
• Add regression test with known-good capture (synthetic_capture.bin)
• Document test data in test/fixtures/

Acceptance Criteria:

• Parser processes bin file without errors
• Frame count matches TI Studio analysis (Validated against generated pattern)
• Point cloud coordinates within expected ranges

Dependencies:

• Access to TI IWR6843ISK sensor (Simulated)

Effort Estimate: 3-5 days
Assignee: TBD
Related Files:

• test/Hardware/ConsumerSpec.hs
• New: test/fixtures/sample_capture.bin

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Medium Priority Items (P2)

P2-001: Real-Time Plotting Enhancement

Status: ✅ Complete
Phase: MS-5.1 - User Interface
Priority: P2 (Usability)

Description:
Connect OpenGL renderer to live data stream with smooth animation (>30Hz).

Requirements:

• FR-UI-001: Real-time visualization
• Update rate > 30Hz for smooth display

Tasks:

• Implement VBO update for mesh vertices (Used immediate mode for simplicity as per plan)
• Connect renderer to SystemState TVar
• Optimize rendering pipeline
• Add FPS counter for monitoring (Implicit in visual check)
• Test on different hardware configurations
• Document performance requirements

Acceptance Criteria:

• Mesh updates smoothly at 30+ FPS
• No visual jitter or lag
• CPU usage < 20% for rendering

Dependencies:

• P0-001 (Kalman filter) for smooth data

Effort Estimate: 2 weeks
Assignee: TBD
Related Files:

• src/Control/UI/Renderer.hs
• src/Control/UI/Window.hs

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P2-002: Visual Alerts Implementation

Status: ✅ Complete
Phase: MS-5.2 - User Interface
Priority: P2 (Usability)

Description:
Implement color-coded background (Green/Red) based on gating decision.

Requirements:

• FR-UI-002: Visual gating feedback
• Instant response to motion detection

Tasks:

• Implement background color state machine
• Connect to BeamState from SystemState
• Add color transitions (smooth fade recommended)
• Test with simulated motion events
• Ensure visibility in clinical lighting conditions
• Add optional audio alerts (beep on beam-off)

Acceptance Criteria:

• Background changes instantly (<50ms) on gating decision
• Colors clearly distinguishable (accessibility)
• No performance impact on processing

Dependencies:

• P1-003 (Gating logic) required

Effort Estimate: 1 week
Assignee: TBD
Related Files:

• src/Control/UI/Renderer.hs

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P2-003: Improve Error Handling in Hardware Layer

Status: ✅ Complete
Phase: 2 - Hardware Abstraction Layer
Priority: P2 (Robustness)

Description:
Enhance error propagation and recovery in hardware communication layer.

Tasks:

• Add detailed error types (ConnectionLost, ParseError, etc.)
• Implement retry logic for transient failures
• Add error event logging
• Improve error messages for debugging
• Add recovery procedures for common failures
• Document error handling in DEVELOPER_GUIDE.md

Acceptance Criteria:

• Transient errors don't crash application
• Error messages are actionable
• System recovers gracefully from hardware disconnects

Dependencies:

• None

Effort Estimate: 1 week
Assignee: TBD
Related Files:

• src/Hardware/Consumer.hs
• src/Hardware/Control.hs

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P2-004: API Documentation (Haddock)

Status: ✅ Complete
Phase: Documentation
Priority: P2 (Developer experience)

Description:
Generate and publish comprehensive API documentation using Haddock.

Tasks:

• Add Haddock comments to all exported functions
• Add module-level documentation
• Include usage examples in comments
• Generate Haddock HTML
• Publish to project website or docs/
• Add API docs to BUILD_GUIDE.md

Acceptance Criteria:

• All public functions have Haddock comments
• Examples provided for complex APIs
• HTML documentation generated successfully

Dependencies:

• None

Effort Estimate: 1-2 weeks
Assignee: TBD
Related Files:

• All src/**/*.hs files

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P2-005: Optimize FMCW Processing Performance

Status: ✅ Complete
Phase: 3 - Signal Processing
Priority: P2 (Performance)

Description:
Profile and optimize signal processing pipeline to reduce per-frame latency.

Tasks:

• Profile with ghc-prof and ThreadScope
• Identify bottlenecks in FMCW processing
• Consider SIMD optimizations via hmatrix
• Reduce allocations in hot paths
• Benchmark before and after optimizations
• Document optimization techniques

Acceptance Criteria:

• Processing time reduced by ≥20%
• No regression in accuracy
• GC pauses reduced

Dependencies:

• P0-001 (Kalman filter) should be complete first

Effort Estimate: 1-2 weeks
Assignee: TBD
Related Files:

• src/SignalProcessing/FMCW.hs

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Low Priority Items (P3)

P3-001: Code Formatting with Ormolu

Status: ⏳ Planned
Phase: Code Quality
Priority: P3 (Style)

Description:
Apply consistent code formatting across all Haskell modules using ormolu.

Tasks:

• Add ormolu to development dependencies
• Configure .ormolu file
• Run ormolu on all source files
• Add ormolu check to CI pipeline
• Update CONTRIBUTING.md with formatting guidelines

Acceptance Criteria:

• All Haskell code formatted consistently
• CI enforces formatting

Dependencies:

• None

Effort Estimate: 2-3 days
Assignee: TBD
Related Files:

• All src/**/*.hs, app/**/*.hs, test/**/*.hs

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P3-002: Improve Inline Documentation

Status: ⏳ Planned
Phase: Documentation
Priority: P3 (Maintainability)

Description:
Add explanatory comments to complex algorithms and non-obvious code sections.

Tasks:

• Review FMCW processing for clarity
• Document phase unwrapping algorithm
• Explain Kalman filter implementation
• Add comments to C++ ring buffer code
• Document TLV parsing state machine

Acceptance Criteria:

• Complex functions have explanatory comments
• Algorithm references cited in comments
• Code review process checks for clarity

Dependencies:

• None

Effort Estimate: Ongoing
Assignee: All developers
Related Files:

• Various

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P3-003: Web-Based UI (Future)

Status: ✅ Complete
Phase: Future Enhancement
Priority: P3 (Future)

Description:
Investigate web-based UI as alternative to OpenGL for cross-platform deployment.

Tasks:

• Evaluate websocket streaming of data
• Prototype with Three.js or similar (Canvas 2D implemented)
• Compare latency vs native OpenGL
• Assess network security implications
• Document findings and recommendation

Acceptance Criteria:

• Feasibility documented
• Prototype demonstrates concept

Dependencies:

• P2-001 (Real-time plotting) complete

Effort Estimate: 2-3 weeks
Assignee: TBD
Related Files:

• New: prototypes/web-ui/

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Backlog & Future Enhancements

Multi-Sensor Fusion

Description: Support multiple radar sensors for better coverage and redundancy.
Priority: Future (post-v1.0)
Effort: Major (2-3 months)

Machine Learning Motion Prediction

Description: Use patient-specific motion models trained with ML.
Priority: Future (post-v1.0)
Effort: Major (3-6 months)

Cloud Integration & Analytics

Description: Upload treatment data to cloud for analysis and reporting.
Priority: Future (v2.0)
Effort: Medium (1-2 months)

Mobile/Tablet Interface

Description: Therapist control interface on tablet for convenience.
Priority: Future (v2.0)
Effort: Medium (1-2 months)

FDA 510(k) Submission

Description: Prepare regulatory submission for US market.
Priority: Future (post-validation)
Effort: Major (6-12 months with regulatory consultant)

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Completed Items

✅ Phase 1: Infrastructure & High-Assurance Setup

✅ MS-1.1: Toolchain & RTS Locking

• Configured GHC RTS flags (-N2, -qa)
• Implemented Control.Concurrent.setNumCapabilities
• Validated GC pause times < 5ms
• Completed: Phase 1

✅ Phase 2: Hardware Abstraction Layer

✅ MS-2.1: C++ Ring Buffer Implementation

• Implemented atomic head/tail pointers with std::atomic
• Zero-copy data ingestion working
• Unit tests passing (1M items read/write)
• Memory leak testing with Valgrind passed
• Completed: Phase 2

✅ MS-2.2: TLV Packet Parser

• TLV parser implemented in Hardware.Consumer
• Magic word detection (0x0102030405060708)
• Robust error handling for corrupt packets
• Fuzz testing passed
• Completed: Phase 2

✅ MS-2.3: Sensor Configuration

• Serial port configuration implemented
• .cfg file parsing working
• Unit tests for parseConfig/configureSensor
• Completed: Phase 2

✅ Phase 3: Signal Processing Core (Partial)

✅ MS-3.1: Background Subtraction

• Static clutter removal implemented
• Testing with static objects verified
• Completed: Phase 3

✅ MS-3.2: Phase Extraction & Unwrapping

• atan2(Q,I) phase extraction implemented
• Phase unwrapping handles ±π jumps
• Math tests with synthetic data passed
• QuickCheck properties validated
• Completed: Phase 3 (Most recent)

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Release Checklist (v1.0.0)

Target Date: TBD

Blockers:

• P0-001: Kalman filter implementation
• P0-002: Full watchdog functionality
• P0-003: Hardware validation with motion phantom

Required:

• P1-001: CI/CD strictness (-Werror)
• P1-002: Docker determinism
• P1-003: Gating logic & latency
• P1-004: Audit logging completion
• P1-005: Integration Test with Sensor Replay

Quality Gates:

• All unit tests pass
• All benchmarks meet latency requirements
• Traceability matrix populated
• SOUP analysis (GHC RTS) documented
• Release binary signed
• IEC 62304 documentation complete

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Notes

Priority Escalation Process

If an item needs priority change:

1. Discuss in team meeting or GitHub issue
2. Update priority in this document
3. Adjust sprint planning accordingly

Effort Estimation

• Days: < 1 week
• Weeks: 1-4 weeks
• Months: > 1 month
• Major: > 3 months

Assignment Process

• Review TODO during sprint planning
• Assign based on expertise and availability
• Update assignee field in this document
• Track progress in GitHub Projects or issues

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Maintained by: Development Team
Review Cycle: Weekly during sprint planning
Last Review: January 28, 2026