EM21 Environmental Monitor


Product Specifications


  • 6.3 x 6.3 x 2.25 cm (2.48 x 2.48 x .89 in)


  • 75.6 g

Operating Temperature

  • -40° to 60°C


  • 3+ year battery life, user-replaceable AA battery

Probe (EM22)

  • Stainless steel (5.0 x .33 cm), 28AWG hermetically-sealed PFA jacket (sterilizable). Total probe and wire length = 120 cm

Ingress Protection

  • IP67 rated waterproof and dustproof per IEC standard 60529; designed for splash, spray, and dust (body no intended for prolonged submersion)

Data Logging Capacity

  • When vehicle is on, typical power draw is 1W (3 months)

Data Upload

  • Automatic (zero touch) wireless data upload via Samsara gateway

Included Sensors

  • Temperature (Built-In):
    Range: -40° to 60° C (limited by operating range)
    Accuracy: -10° to 60° C, Typical: ±0.3°, C Max: ±0.4° C -40° to -10° C, Typical: ±0.7°, C Max: ±0.9° C

Temperature (External Probe – EM22)

  • Range: -55° to 100° C
  • Accuracy: -55° to 100° C Typical: ±1.0° C
  • Time Constant: 5.0s (oil bath)


  • Range: 0-95% RH
  • Accuracy: 0 to 80% RH Typical: ±2.0% Max: ±3.0% 80 to 90% RH Typical: ±2.5% Max: ±3.8% 90 to 95% RH Typical: ±3.0% Max: ±4.5%
  • Time Constant: 18s (1 m/s airflow)


  •  Samples every 4 seconds, transmits new data to the cloud in real-time


  • Automatically detects and connects to any sensor associated with same account

Wireless Range

  • 100 ft / 30 m (line of site). Actual range depends on RF interference, building materials, and physical obstacles

Radio Frequency

  •  2.4 Ghz, proprietary low-power sensor data protocol

Visibility and Management

  •  Real-time visibility, SMS and email alerts, and historical reports via Samsara Cloud dashboard for web and mobile devices

All-Inclusive License

  • Requires EM license, which includes maintenance and support, dashboard access, sensor data storage, and feature updates

STARTING AT $10.50 PER MONTH: 1, 3, 5 year license options

The EM21 Wireless Environmental Monitor is a wireless, waterproof, data-logging sensor that monitors temperature and humidity. The EM21 is ideal for ensuring food safety during transportation, monitoring warehouse conditions, and other applications that rely on environmental data to ensure quality and maintain compliance. The EM21 is a part of a complete solution designed to enhance efficiency, safety, customer service, and compliance.

  • Wirelessly monitors temperature and humidity
  • Durable waterproof design with LCD display
  • Class-leading electronics with multi-year battery life with single AA battery
  • Scales from small operations to thousands of assets
  • Easy plug-and-play installation takes 15 minutes

All Samsara hardware has a warranty that lasts as long as a valid license for said hardware is maintained. For more information, click here.


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