Ultrasonic Wind and Rain Combo Sensor

Environmental monitoring programmes that require wind and rainfall data typically deploy separate instruments — a cup anemometer and wind vane for wind, a tipping bucket rain gauge for precipitation. Each adds mounting complexity, maintenance requirements, and failure points. The Sensorbee Wind and Rain Combo Sensor combines ultrasonic wind measurement with infrared optical rainfall detection in a single unit with no moving parts. Wind speed to 45 m/s, direction to ±1°, and precipitation with 0.2 mm resolution — all from one maintenance-free device that integrates with the Air Pro 2 and Air Lite monitoring platforms.

How It Works

The combo sensor integrates two measurement technologies in a single housing:

Ultrasonic wind measurement uses the same transit-time principle as the standalone wind sensor (SB3611). Pairs of ultrasonic transducers emit sound pulses along two perpendicular axes. The difference in transit times between upwind and downwind pulses on each axis resolves both wind speed and direction simultaneously, with no rotating parts.

Infrared optical rainfall detection measures precipitation using a fundamentally different approach from traditional tipping bucket rain gauges. An infrared optical sensor detects raindrops as they pass through the measurement volume, determining rainfall intensity and accumulation without the mechanical tipping mechanism that dominates conventional rain gauge designs.

This dual-technology approach means the entire sensor operates without a single moving part — no cups, vanes, bearings, or tipping buckets.

Why Combined Wind and Rain Data Matters

Wind and rainfall data together provide the meteorological context needed for comprehensive environmental assessment:

• Dust suppression management — construction site dust management plans use wind speed thresholds to trigger suppression activities and rainfall data to determine when natural wetting makes suppression unnecessary. The combo sensor provides both inputs from a single instrument
• Dispersion modelling — atmospheric dispersion models use wind speed, direction, and atmospheric stability (influenced by cloud cover and precipitation) to predict pollutant spread. On-site meteorological data improves model accuracy
• Wet deposition assessment — rainfall washes pollutants from the atmosphere, affecting both air quality and surface water quality. Concurrent precipitation and air quality data supports wet deposition analysis
• Environmental permit compliance — monitoring programmes required by environmental permits often specify both wind and precipitation measurement. The combo sensor satisfies both requirements from a single mounting point
• Data quality context — some air quality measurements are affected by rainfall (particularly light-scattering PM sensors). Concurrent precipitation data flags periods where meteorological conditions may have influenced pollutant readings

No Moving Parts: Eliminating Maintenance

The elimination of moving parts is the combo sensor's primary operational advantage:

No tipping bucket — traditional rain gauges use a small bucket that fills and tips at a calibrated volume, counting tips to calculate rainfall. These mechanisms block with debris, insects, and bird droppings. The infrared optical approach has no funnel to clog, no pivot to seize, and no bucket to contaminate.

No cup anemometer — rotating cups wear bearings, accumulate ice, and lose calibration accuracy over time. The ultrasonic wind measurement is electronically stable and requires no mechanical calibration.

Over 2 years operational life without maintenance intervention — reducing site visits, maintenance costs, and the data gaps that occur when instruments are offline for servicing.

Measurement Performance

Wind performance matches the standalone wind sensor: 1% RMS accuracy at 10 m/s reference speed, ±1° direction accuracy, and 0–45 m/s speed range. The 1 m/s threshold provides reliable measurement across the wind speed range relevant to environmental monitoring and construction site safety.

Rainfall performance delivers 0.2 mm resolution with ±10% accuracy. The infrared optical method measures rainfall intensity continuously rather than in discrete bucket-tip increments, providing smoother precipitation data without the stepwise artefacts that characterise tipping bucket recordings. The rain sensor operates from 0 to +55°C — note the higher lower limit compared to the wind function, as the optical sensor requires above-freezing conditions for liquid precipitation measurement.

Wind Sensor or Wind and Rain Combo?

The choice depends on whether your monitoring programme requires precipitation data:

• Wind sensor only (SB3611) — 450 g, wind speed and direction only. Choose this when rainfall measurement is not required by your monitoring plan or is provided by a separate instrument
• Wind and rain combo (SB3602) — 950 g, wind speed, direction, and rainfall. Choose this when both wind and precipitation data are needed, particularly for construction site environmental monitoring where dust management plans require both parameters

Both sensors share the same wind measurement specifications and mounting system. The combo sensor adds approximately 500 g and the infrared rain detection capability.

Integration With Sensorbee Platforms

The combo sensor connects to the Air Pro 2 and Air Lite, providing wind and rainfall data alongside air quality, noise, and vibration measurements. The Sensorbee Cloud presents all meteorological parameters alongside environmental data, enabling:

• Rainfall-flagged air quality data — identify measurement periods where precipitation may have influenced particulate matter readings
• Wind rose and precipitation analysis — visualise wind patterns and rainfall accumulation over monitoring periods
• Automated dust management alerts — combine wind speed thresholds with rainfall status to determine when dust suppression activities are required
• Complete environmental reporting — meteorological data integrated with all other monitoring parameters for comprehensive site reports

For a complete weather station capability, combine the wind and rain combo with:

• Precision temperature and humidity sensor (SB3104) — ambient temperature and humidity
• Pyranometer (SB3662) — solar radiation measurement

Installation

Mount the combo sensor at an appropriate height with clear exposure to wind and precipitation from all directions. The included universal bracket and hose clamps support pole and wall mounting. Position away from buildings and structures that would obstruct wind flow or create rain shadow effects.

Connect the cable to the Air Pro 2 or Air Lite base station. The platform automatically detects both the wind and rain measurement channels and begins logging data. No calibration, orientation adjustment, or software configuration is needed at the deployment site.

The rain sensor element should remain unobstructed — avoid mounting positions where overhanging structures could shield the sensor from rainfall or cause dripping artefacts that produce false precipitation readings.

Applications

• Construction site weather monitoring — combined wind and rainfall data for dust management plans, environmental monitoring programmes, and safe working condition assessment
• Environmental monitoring stations — complete meteorological data alongside air quality measurements for regulatory compliance and environmental assessment
• Dispersion modelling support — on-site wind and precipitation data for atmospheric dispersion model validation and input
• Agricultural weather stations — wind and rainfall monitoring for crop management, irrigation planning, and frost risk assessment
• Renewable energy assessment — wind resource data alongside precipitation patterns for site evaluation and performance analysis
• Event weather monitoring — portable deployment for outdoor events where wind and rain conditions affect safety and operational decisions

Frequently Asked Questions

Can the rain sensor measure snowfall?

The infrared optical sensor measures liquid precipitation. Snowfall, sleet, and freezing rain below 0°C are outside the rain sensor's operating range. The wind measurement function continues operating down to -15°C regardless of precipitation type.

How does the optical rain sensor compare to a tipping bucket?

Tipping buckets are the traditional standard and offer very precise volumetric measurement when properly maintained. The infrared optical sensor trades some absolute accuracy (±10%) for zero maintenance, no moving parts, and continuous measurement without discrete tipping artefacts. For environmental monitoring applications where ±10% rainfall accuracy is acceptable, the optical approach eliminates the maintenance burden of keeping tipping bucket mechanisms clean and functional.

Does heavy rain affect wind measurements?

The ultrasonic wind measurement operates through rainfall without significant impact. Very heavy precipitation may cause brief signal attenuation, but the sensor algorithms are designed to maintain wind measurement quality through all but the most extreme rainfall events.

Is the mounting bracket included?

Yes — the sensor ships with a universal wall/pole bracket and two hose clamps, ready for installation on standard poles or wall surfaces.

Can I upgrade from the wind-only sensor to the combo?

The wind sensor (SB3611) and wind and rain combo (SB3602) use the same mounting system. Upgrading involves replacing the sensor unit on the existing mount and connecting the new cable to the base station.