The SEMR226 is a radar rainfall sensor. A flat radar module detects falling precipitation and reports its intensity and type: rain, snow or hail. It detects the start and end of rain faster than a mechanical gauge. It has no moving parts, so it is almost maintenance-free, and it is small and uses little energy. It connects to a SpaceEcho station and reports to EchoCloud.
Distinguishes no precipitation, rain, snow and hail.
Quick start and end detection
More sensitive and faster than a mechanical rain gauge.
Not affected by leaves
Leaves or other objects on the sensing surface do not stop it detecting rain.
No heater needed
It does not need a heating device to prevent icing.
Three interfaces
RS-485, RS-232 and SDI-12, with Modbus, NMEA-0183 or ASCII.
Applications
Weather stations
Rainfall detection.
Smart city systems
Local rainfall data.
River flood control
Monitoring rainfall intensity.
Specifications
Precipitation types
No precipitation, rain, snow, hail
Measuring range
0.01–200 mm/h (liquid precipitation)
Accuracy
±10 % of the measured value (liquid precipitation)
Resolution
0.1 mm
Drop size range
0.5–5.0 mm
Radar frequency
24 GHz
Measurement surface
8 cm²
Sample rate
1 s
Communication interface
RS-485, RS-232, SDI-12
Communication protocol
Modbus, NMEA-0183, ASCII
Supply voltage
7–30 V DC; 130 mA at 12 V
Power consumption
1.6 W
Operating temperature
−40–70 °C
Operating humidity
0–100 %
Dimensions
Ø105 × 178 mm
Weight
0.65 kg
Material
Aluminium alloy and ABS
Choosing a rain sensor
Two sensors measure rainfall on a SpaceEcho station. They work on different principles, and some sites use both.
Radar — SEMR226
No moving parts, so it needs little maintenance. It reports rain, snow or hail, and detects the start and end of rain faster than a mechanical gauge. Range 0.01–200 mm/h, accuracy ±10 % of the value for liquid precipitation. Limit: a wider error than the bucket gauge.
Bucket — SEM404
Accuracy of ±3 % over 0–4 mm/min, from collected rainfall. Limits: it does not report the type of precipitation, and the collector needs regular cleaning. See the Bucket Rain Gauge.
