Monthly Archives: January 2022

WTN300: Wireless Cold Chain Temperature/RH Sensor

The WTN300 is a wireless temperature/RH sensor node operating in the Sub-GHz band. It is powered by two AAA batteries. Sleep mode power consumption is less than 2 microamps.

Multiple geographies supported

  • FCC (900 MHz band) certified Radio
  • ETSI (868 MHz band) certified Radio
  • India (865-867 MHz band) compliant Radio

This node talks to a WiSense gateway with WIFI, RS-232, RS-485, serial over USB simple UART interface.

The node supports three different types of temperature sensors

  • DS18B20 over I2C link (-55 deg C to + 50 degrees C)
  • PT-100/PT-1000 (-100 deg C to +50 degrees C)
  • TMP102 for ambient air sensing (-5 to +50 degrees C)

It uses the HIH8120 for relative humidity.

Installation is simple. Insert two AAA batteries and switch on the node. It will automatically connect to the gateway and start sending data. The gateway will send data to the configured endpoint which can be local or in the cloud. Supported standards/formats include MQTT, JSON, HTTP, HTTPS etc.

WTN300 Wireless Temperature/RH node


WTN300 Wireless Temperature/RH node


The sensor node mounted on the outside a refrigeration unit. You can see a thin flat cable connecting this external enclosure to the sensing element inside the refrigerator. You can also see a half-wave dipole antenna.


3D printed enclosure inside a refrigeration unit. The connector cable is thin and flat to ensure a good seal is maintained when the door is closed.


Graph showing data from five sensor nodes deployed in five different refrigerators at a customer location.
Y-axis is temperature in degree C while X-axis is time.

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