HOBO MX2201 Pendant Temperature Data Logger

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The HOBO MX2201 waterproof temperature logger leverages the power of Bluetooth Low Energy (BLE) to deliver accurate temperature measurements straight to your mobile device with Onset's free HOBOconnect app. Designed for durability, this compact waterproof logger is ideal for measuring temperature in streams, lakes, oceans, and soil environments. Data collection in the field has never been easier!

Add the MX Gateway for remote access to your data in Onset's cloud-based HOBOlink software (indoor deployments).

Mounting Requirements: It is very important that the logger housing does not get distorted when mounted. When mounting these loggers to any non-flat surface, such as rebar or posts, we recommend using the Mounting Boot (BOOT-MX2201-2201). This boot is also useful for mounting loggers so they can be easily removed for service.

Manufactured by: Onset
Model: HOBO MX2201 Pendant Temperature Data Logger

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Soil temperature
Water temperature


Temperature Sensor (MX2201 and MX2202)
Range -20° to 70°C (-4° to 158°F) in air
-20° to 50°C (-4° to 122°F) in water

Accuracy ±0.5°C from -20° to 70°C (-4° to 158°F)
Resolution 0.04°C (0.072°F)
Drift <0.1°C (0.18°F) per year
Response Time 17 minutes typical to 90% in air moving 1 m/s, unmounted
7 minutes typical to 90% in stirred water, unmounted
Radio Power 1 mW (0 dBm)
Transmission Range Approximately 30.5 m (100 ft) line-of-sight
Wireless Data Standard Bluetooth Smart (Bluetooth Low Energy, Bluetooth 4.0)
Logger Operating Range -20° to 70°C (-4° to 158°F) in air
Logging Rate 1 second to 18 hours
Buoyancy (Fresh Water) 2g (0.07 oz) positive
Waterproof To 30.5 m (100 ft)
Memory 96,000 measurements
Battery CR2032 3V lithium, user replaceable
Battery Life 1 year typical at 25°C (77°F) with logging interval of 1 minute and Bluetooth Always On in software.
2 years typical at 25°C (77°F) with logging interval of 1 minute and Bluetooth Always Off in software.
Faster logging intervals and statistics sampling intervals, burst logging, remaining connected with the app, excessive downloads, and paging may impact battery life.
To ensure proper battery installation, see Battery Information for detailed instructions on replacing the battery.
Time Accuracy ± 1 minute per month at 25°C (77°F)
Full Memory Download Approximately 45 seconds; may take longer the farther the device is from the logger
Wetted Materials Polypropylene case, EPDM O-ring
Dimensions 3.35 x 5.64 x 1.8 cm (1.32 x 2.22 x 0.69 inches)
Weight 12.75 g (.45 oz)