Onset HOBO Temperature / RH Bluetooth Data Loggers ²⁶

HOBO Temperature/RH Bluetooth Data Loggers

Advanced HOBO® data loggers for precise monitoring of multiple environmental variables

The HOBO® MX2301A, MX230X, MX2305, MX2302A, MX2303, and MX2304 Data Loggers are versatile and reliable devices designed to monitor a wide range of environmental parameters across industrial, agricultural, and scientific applications. These loggers are equipped with high-precision sensors to measure variables such as temperature, humidity, pressure, and other critical factors, and they feature extended data storage capabilities. They are ideal for use in outdoor environments, laboratories, or industrial facilities that require continuous monitoring.

Each model is configured to meet specific needs, ranging from options with multiple inputs to devices with advanced measurement and wireless communication capabilities. The devices are designed to simplify installation and data analysis, with connectivity options such as Bluetooth to enable easy real-time data transmission to mobile devices.

Key Features

• MX2301A Model: A weatherproof data logger with integrated temperature and relative humidity sensors. Leveraging Bluetooth technology for easy setup and data download directly to your mobile device or Windows computer running Onset’s free HOBOconnect app, this logger delivers high-accuracy measurements even in harsh outdoor environments.
• MX2306 and MX2307 Models: Fully integrated, low-cost soil moisture data loggers with Bluetooth wireless data download. Available in two models—one that measures soil moisture (HOBO MX2306) and another that measures both soil moisture and soil temperature (HOBO MX2307)—these loggers are ideal for researchers and growers seeking accurate data to conserve water, improve crop yields, reduce harmful runoff, and protect ecosystems.
• MX2302A Model: A weatherproof data logger with external temperature and relative humidity sensors. Using Bluetooth technology for easy setup and data download directly to your mobile device or Windows computer running the free Onset HOBOconnect app, this logger provides high-accuracy measurements in harsh outdoor environments.
• MX2303 Model: A weatherproof data logger with two external temperature sensors. Using Bluetooth technology for easy setup and data download directly to your mobile device or Windows computer running the free Onset HOBOconnect app, this logger offers high-precision measurements in harsh outdoor environments.
• MX2304 Model: A weatherproof data logger with one external temperature sensor. Using Bluetooth technology for easy setup and data download directly to your mobile device or Windows computer running the free Onset HOBOconnect app, this logger provides high-accuracy measurements in harsh outdoor environments.
• MX2305 Model: A weatherproof data logger with one internal temperature sensor. Using Bluetooth technology for easy setup and data download directly to your mobile device or Windows computer running the free Onset HOBOconnect app, this logger delivers high-accuracy measurements in harsh outdoor environments.

• Specifications
• In the Box
• Required Items
• Optional Items

• Temperature Sensor
  Range	MX2301A and MX2305 internal sensors: -40 to 70°C (-40 to 158°F) MX2302A external temperature sensor: -40 to 70°C (-40 to 158°F) MX2303 and MX2304 external sensors: -40 to 100°C (-40 to 212°F), with sensor tip and cable immersed in fresh water up to 50°C (122°F) for one year
  Accuracy	±0.25°C from -40 to 0°C (±0.45°F from -40 to 32°F) ±0.2°C from 0 to 70°C (±0.36°F from 32 to 158°F) ±0.25°C from 70 to 100°C (±0.45°F from 158 to 212°F), MX2303 and MX2304 only
  Resolution	MX2301A and MX2302A: 0.02°C (0.036°F) MX2303, MX2304, and MX2305: 0.04°C (0.072°F)
  Drift	0.01°C (0.018°F) per year

  
  

  Relative Humidity Sensor* (MX2301A and MX2302A only)
  Range	0 to 100% RH, -40° to 70°C (-40° to 158°F); exposure to conditions below -20°C (-4°F) or above 95% RH may temporarily increase the maximum RH sensor error by an additional 1%
  Accuracy	±2.5% from 10% to 90% RH (typical) up to a maximum of ±3.5% including hysteresis at 25°C (77°F); below 10% RH and above 90% RH ±5% typical
  Resolution	0.01%
  Drift	1% per year typical

  
  

  Response Time (typical, to 90% of change)
  Temperature	Without solar radiation shield: MX2301A internal sensor: 17 minutes in air moving at 1 m/s With RS1/M-RSA solar radiation shield: MX2301A internal sensor: 24 minutes in air moving at 1 m/s With RS3-B solar radiation shield: Same as above
  MX2302A External Sensor	Without solar radiation shield: 3 minutes, 45 seconds in air moving at 1 m/s With RS1/M-RSA solar radiation shield: 7 minutes, 45 seconds in air moving at 1 m/s With RS3-B solar radiation shield: 6 minutes, 30 seconds in air moving at 1 m/s
  MX2303/MX2304 External Sensors	Without solar radiation shield: 3 minutes in air moving at 1 m/s; 20 seconds in stirred water With RS1/M-RSA solar radiation shield: 7 minutes in air moving at 1 m/s With RS3-B solar radiation shield: 4 minutes in air moving at 1 m/s
  MX2305 Internal Sensor	Without solar radiation shield: 17 minutes in air moving at 1 m/s With RS1/M-RSA solar radiation shield: 24 minutes in air moving at 1 m/s With RS3-B solar radiation shield: Same as above

  
  

  RH
  MX2301A Internal Sensor	Without solar radiation shield: 30 seconds in air moving at 1 m/s With RS1/M-RSA solar radiation shield: 40 seconds in air moving at 1 m/s With RS3-B solar radiation shield: Same as above
  MX2302A External Sensor	Without solar radiation shield: 15 seconds in air moving at 1 m/s With RS1/M-RSA solar radiation shield: 30 seconds in air moving at 1 m/s With RS3-B solar radiation shield: 30 seconds in air moving at 1 m/s

  
  

  Logger
  Operating Range	-40° to 70°C (-40° to 158°F)
  Radio Power	1 mW (0 dBm)
  Transmission Range	Approximately 30.5 m (100 ft) line of sight
  Wireless Data Standard	Bluetooth Low Energy (Bluetooth Smart)
  Logging Rate	1 second to 18 hours
  Logging Modes	Fixed interval (normal, statistical) or burst
  Memory Modes	Wrap when full or stop when full
  Start Modes	Immediate, push-button, date & time, or next interval
  Stop Modes	When memory is full, push-button, date & time, or after a set logging period
  Time Accuracy	±1 minute per month from 0° to 50°C (32° to 122°F)
  Battery Type	3.6-volt 2/3 AA lithium battery, user-replaceable
  Battery Life	2 years typical with 1-minute logging interval and Bluetooth Always On enabled; 5 years typical with 1-minute logging interval and Bluetooth Always On disabled. Faster logging intervals, statistical sampling intervals, burst logging, staying connected to the app, excessive downloads, and paging may impact battery life.
  Memory	MX2301A and MX2302A: 128 KB (63,488 measurements max) MX2303, MX2304, and MX2305: 128 KB (84,650 measurements max)
  Full Memory Download Time	Approximately 60 seconds; may take longer the farther the device is from the logger
  Dimensions	Logger enclosure: 10.8 x 5.08 x 2.24 cm External temperature sensor diameter: 0.53 cm External temperature/RH sensor diameter: 1.17 cm External sensor cable length: 2 m Solar radiation shield mount: 10.8 x 8.3 cm
  Weight	Logger: 75.5 g Solar radiation shield mount: 20.4 g
  Materials	Acetal, silicone gasket, stainless steel screws

• • 1x HOBO Temperature Data Logger
  • Screws
  • Cable Ties
• • HOBOMobile App (Free)
  • Compatible Smartphone or Tablet
• • Accessories
    
    • Solar Radiation Shields
    • NIST Temperature Point Certification
    • NIST Relative Humidity Initial Calibration Service Certification
    • NIST Traceable Certification Installation Charge
    • Certificate of Compliance
    Maintenance
    
    • Replacement Batteries (2-pack)