terra-view/docs/SOUND_LEVEL_METERS_DASHBOARD.md

Sound Level Meters Dashboard

Overview

The Sound Level Meters dashboard is a new feature in SFM (soon to be rebranded as Terra-view) that provides real-time monitoring and control of Rion NL-43/NL-53 sound level meters through the SLMM backend integration.

Features

1. Dashboard Summary Statistics

• Total Units: Count of all SLM devices in the system
• Deployed Units: Active devices currently in the field
• Active Now: Units that have checked in within the last hour
• Benched Units: Devices not currently deployed

2. Unit List (Sidebar)

• Searchable list of all deployed SLM units
• Real-time status indicators:
  • 🟢 Green: Active (recently checked in)
  • ⚪ Gray: No check-in data
• Quick unit information:
  • Device model (NL-43, NL-53, etc.)
  • Location/address
  • Network address (IP:port)
• Click any unit to view its live data

3. Live View Panel

When a unit is selected, the live view panel displays:

Control Buttons

• Start: Begin measurement
• Pause: Pause current measurement
• Stop: Stop measurement
• Reset: Reset measurement data
• Start Live Stream: Open WebSocket connection for real-time DRD data

Real-time Metrics

• Lp (Current): Instantaneous sound level in dB
• Leq (Average): Equivalent continuous sound level
• Lmax (Peak): Maximum sound level recorded
• Lmin: Minimum sound level recorded

Live Chart

• Real-time line chart showing Lp and Leq over time
• 60-second rolling window (adjustable)
• Chart.js-powered visualization with dark mode support
• No animation for smooth real-time updates

Device Information

• Battery level and power source
• Frequency weighting (A, C, Z)
• Time weighting (F, S, I)
• SD card remaining space

Architecture

Frontend Components

Main Template

File: templates/sound_level_meters.html

The main dashboard page that includes:

• Page header and navigation integration
• Stats summary section (auto-refreshes every 10s)
• Two-column layout: unit list (left) + live view (right)
• JavaScript functions for unit selection and WebSocket streaming

Partial Templates

1. slm_stats.html - Summary statistics cards

   • Auto-loads on page load
   • Refreshes every 10 seconds via HTMX

2. slm_unit_list.html - Searchable unit list

   • Auto-loads on page load
   • Refreshes every 10 seconds via HTMX
   • Supports search filtering

3. slm_live_view.html - Live data panel for selected unit

   • Loaded on-demand when unit is selected
   • Includes Chart.js for visualization
   • WebSocket connection for streaming data

4. slm_live_view_error.html - Error state display

Backend Components

Router: backend/routers/slm_dashboard.py

Endpoints:

GET /api/slm-dashboard/stats

Returns HTML partial with summary statistics.

GET /api/slm-dashboard/units?search={term}

Returns HTML partial with filtered unit list.

GET /api/slm-dashboard/live-view/{unit_id}

Returns HTML partial with live view panel for specific unit.

• Fetches unit details from database
• Queries SLMM API for current measurement state
• Queries SLMM API for live status (DOD data)

POST /api/slm-dashboard/control/{unit_id}/{action}

Sends control commands to SLMM backend.

• Valid actions: start, stop, pause, resume, reset
• Proxies to http://localhost:8100/api/nl43/{unit_id}/{action}

Integration with SLMM

The dashboard communicates with the SLMM backend service running on port 8100:

REST API Calls:

• GET /api/nl43/{unit_id}/measurement-state - Check if measuring
• GET /api/nl43/{unit_id}/live - Get current DOD data
• POST /api/nl43/{unit_id}/start|stop|pause|resume|reset - Control commands

WebSocket Streaming:

• WS /api/nl43/{unit_id}/live - Real-time DRD data stream
• Proxied through SFM at /api/slmm/{unit_id}/live
• Streams continuous measurement data for live charting

Database Schema

Table: roster

SLM-specific fields in the RosterUnit model:

device_type = "slm"  # Distinguishes SLMs from seismographs
slm_host = String                   # Device IP or hostname
slm_tcp_port = Integer               # TCP control port (default 2255)
slm_model = String                   # NL-43, NL-53, etc.
slm_serial_number = String           # Device serial number
slm_frequency_weighting = String     # A, C, or Z weighting
slm_time_weighting = String          # F (Fast), S (Slow), I (Impulse)
slm_measurement_range = String       # e.g., "30-130 dB"
slm_last_check = DateTime            # Last communication timestamp

Navigation

The Sound Level Meters page is accessible from:

• URL: /sound-level-meters
• Sidebar: "Sound Level Meters" menu item (between Fleet Roster and Projects)
• Icon: Speaker/sound wave SVG icon

Real-time Updates

The dashboard uses three mechanisms for real-time updates:

1. HTMX Polling (10-second intervals)

   • Summary statistics
   • Unit list
   • Ensures data freshness even without user interaction

2. On-Demand Loading (HTMX)

   • Live view panel loads when unit is selected
   • Control button responses

3. WebSocket Streaming (continuous)

   • Real-time DRD data for live charting
   • User-initiated via "Start Live Stream" button
   • Automatically closed on page unload or unit change

Measurement Duration Tracking

Important: The NL-43/NL-53 devices do not expose measurement duration via their API. Elapsed time and interval counts are only visible on the device's on-screen display (OSD).

Solution: Track measurement start time in your application when calling the /start endpoint:

// When starting measurement
const startTime = new Date();
localStorage.setItem(`slm_${unitId}_start`, startTime.toISOString());

// Calculate elapsed time
const startTime = new Date(localStorage.getItem(`slm_${unitId}_start`));
const elapsed = (new Date() - startTime) / 1000; // seconds

Future Enhancement: SLMM backend could store measurement start times in a database table to track duration across sessions.

Testing

Add Test Data

Use the included script to add test SLM units:

python3 add_test_slms.py

This creates:

• 3 deployed test units (nl43-001, nl43-002, nl53-001)
• 1 benched unit (nl43-003)

Running the Dashboard

1. Start SLMM backend (port 8100):

   cd /home/serversdown/slmm
   uvicorn main:app --host 0.0.0.0 --port 8100
   

2. Start SFM (port 8000):

   cd /home/serversdown/sfm/seismo-fleet-manager
   uvicorn backend.main:app --host 0.0.0.0 --port 8000 --reload
   

3. Access dashboard:

   http://localhost:8000/sound-level-meters
   

Testing Without Physical Devices

The dashboard will work without physical NL-43 devices connected:

• Unit list will display based on database records
• Live view will show connection errors (gracefully handled)
• Mock data can be added to SLMM for testing

Future Enhancements

Near-term

1. Measurement Duration Tracking

   • Add database table to track measurement sessions
   • Display elapsed time in live view
   • Store start/stop timestamps

2. Historical Data View

   • Chart historical Leq intervals
   • Export measurement data
   • Comparison between units

3. Alerts & Thresholds

   • Configurable sound level alerts
   • Email/SMS notifications when thresholds exceeded
   • Visual indicators on dashboard

Long-term

1. Map View

   • Display all SLMs on a map (like seismographs)
   • Click map markers to view live data
   • Color-coded by current sound level

2. Batch Operations

   • Start/stop multiple units simultaneously
   • Synchronized measurements
   • Group configurations

3. Advanced Analytics

   • Noise compliance reports
   • Statistical summaries
   • Trend analysis

Integration with Terra-view

When SFM is rebranded to Terra-view:

1. Multi-Module Dashboard

   • Sound Level Meters module (this dashboard)
   • Seismograph Fleet Manager module (existing)
   • Future monitoring modules

2. Project Management

   • Link SLMs to projects
   • Combined project view with seismographs + SLMs
   • Project-level reporting

3. Unified Navigation

   • Top-level module switcher
   • Consistent UI/UX across modules
   • Shared authentication and settings

Technical Notes

HTMX Integration

The dashboard extensively uses HTMX for dynamic updates without full page reloads:

• hx-get: Fetch and swap content
• hx-trigger: Auto-refresh intervals
• hx-swap: Content replacement strategy
• hx-target: Specify update target

Dark Mode Support

All components support dark mode:

• Chart.js colors adapt to theme
• Tailwind dark: classes throughout
• Automatic theme detection

Performance Considerations

• WebSocket connections are per-unit (only one active at a time)
• Chart data limited to 60 points (1 minute) to prevent memory bloat
• Polling intervals balanced for responsiveness vs server load
• Lazy loading of live view panel (only when unit selected)

Files Modified/Created

New Files

• templates/sound_level_meters.html
• templates/partials/slm_stats.html
• templates/partials/slm_unit_list.html
• templates/partials/slm_live_view.html
• templates/partials/slm_live_view_error.html
• backend/routers/slm_dashboard.py
• add_test_slms.py
• docs/SOUND_LEVEL_METERS_DASHBOARD.md

Modified Files

• backend/main.py - Added route and router import
• templates/base.html - Added navigation menu item

Support

For issues or questions:

• Check SLMM API documentation: /home/serversdown/slmm/docs/API.md
• Review SFM changelog: CHANGELOG.md
• Submit issues to project repository

---

Version: 1.0.0 Created: January 2026 Last Updated: January 5, 2026