Air Temperature and Relative Humidity Sensor

The EE181 is a rugged, accurate air temperature and relative humidity (RH) probe that is ideal for long-term, unattended applications. It includes a proprietary coating on the RH element that increases the life of the element and protects it from dirt, dust, salt, or other contaminants. A 1000 Ω PRT measures air temperature for the -40° to +60°C range. For optimum results, the EE181 should be recalibrated annually.

Benefits and Features

  • Well-suited for long-term, unattended applications
  • Accurate, rugged, reliable
  • Outstanding long-term stability
  • Wide operating temperature range
  • User cleanable
  • Compact and easily interchangeable
  • Low power consumption
  • Compatible with most Campbell Scientific dataloggers


Supply Voltage 7 to 30 Vdc (typically powered by the datalogger’s 12 V supply)
Average Current Consumption < 1.2 mA
Filter Description 30 μm pore size, stainless-steel mesh
Startup Time 2 s
Housing Body Material Plastic
Housing Classification IP65
Sensor Diameter 2.1 cm (0.83 in.)
Length 16.0 cm (6.3 in.)
Weight 290 g (10.2 oz) with 5 m cable
Air Temperature
Sensor 1000 Ω Platinum Resistance Thermometer (PRT)
Operating Temperature Range -40° to +60°C
Storage Temperature Range -40° to +80°C
Output Signal Range 0 to 1 Vdc
Accuracy ±0.2°C (at +23°C)
Relative Humidity
Sensor Capacitance
Measurement Range 0 to 100% RH (non-condensing)
Output Signal Range 0 to 1 Vdc
Temperature Dependence Typically 0.03% RH/°C
-NOTE- Accuracy specifications include hysteresis, non-linearity, and repeatability.
Accuracy at -15° to +40°C
  • ±(1.3 + 0.003 • RH reading) % RH (0 to 90% RH)
  • ± 2.3% RH (90 to 100% RH)
Accuracy at -25° to +60°C ± (1.4 + 0.01 • RH reading) % RH
Accuracy at -40° to +60°C ± (1.5 + 0.015 • RH reading) % RH



Sensor Mounts

When exposed to sunlight, the EE181 must be housed in a 10-plate solar radiation shield. Campbell Scientific recommends the MetSpec RAD10E, which uses a double-louvered design that offers improved sensor protection from driving rain, snow, and insect intrusion. This shield also has lower self-heating in bright sunlight combined with higher temperatures (> 24°C [~75°F]) and low wind speeds (< 2 m s-1 [~4.5 mph]), giving a better measurement.

The EE181 will work with R. M. Young 10-plate radiation shields (41003-5 or 41003-5A), but these shields require a special adapter (pn 28415) to accommodate the sensor girth.

The RAD10E and 41003-5 attach to a crossarm, mast, or user-supplied pipe with a 2.5 to 5.3 cm (1.0 to 2.1 in.) outer diameter. The 41003-5A radiation shield attaches to a CM500-series pole or a user-supplied pole with a 5.1 cm (2.4 in.) outer diameter.