The HOBO U12 Temperature/Relative Humidity/Light/External Data Logger contains internal sensors for monitoring three common indoor parameters, as well as 3rd party sensors when using the 4-20 mA cable. A fourth channel accepts a wide range of external sensors, including temperature, AC current, AC voltage, CO2, 4-20mA, and DC voltage cables.


12-bit resolution provides high accuracy
Large memory for long-term deployments or fast sampling
Five models to choose from, with flexible measurement options
Programmable and push button start

 AC Current
Relative Humidity
DC Voltage
AC Voltage
Carbon Dioxide
Light Intensity


Measurement range:
Temperature: -20° to 70°C (-4° to 158°F)
RH: 5% to 95% RH
Light intensity: 1 to 3000 footcandles (lumens/ft2) typical; maximum value varies from 1500 to 4500 footcandles (lumens/ft2)
External input channel (see sensor manual): 0 to 2.5 DC Volts
Temperature: ± 0.35°C from 0° to 50°C (± 0.63°F from 32° to 122°F), see Plot A
RH: ±2.5% from 10% to 90% RH (typical), to a maximum of ±3.5%, see Plot B
 Light intensity: Designed for indoor measurement of relative light levels, see Plot D for light wavelength response
External input channel (see sensor manual): ± 2 mV ± 2.5% of absolute reading
Temperature: 0.03°C at 25°C (0.05°F at 77°F), see Plot A
RH: 0.03% RH
Temperature: 0.1°C/year (0.2°F/year)
RH: <1% per year typical; RH hysteresis 1%
Response time in airflow of 1 m/s (2.2 mph):
Temperature: 6 minutes, typical to 90%
RH: 1 minute, typical to 90%
Time accuracy: ± 1 minute per month at 25°C (77°F), see Plot C
Operating temperature:
Logging: -20° to 70°C (-4° to 158°F)
Launch/readout: 0° to 50°C (32° to 122°F), per USB specification
Battery life: 1 year typical use
Memory: 64K bytes (43,000 12-bit measurements)
Weight: 46 g (1.6 oz)
Dimensions: 58 x 74 x 22 mm (2.3 x 2.9 x 0.9 inches)
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).

Producing Area:USA