Humidity and Temperature Sensor with EFM Processor and Dual RS232 Interfaces

  • 2495

We currently have 2 in stock.


This module contains a Measurement Specialties HTU21D(F) Humidity and Temperature Sensor.

This sensor is a fully calibrated humidity and temperature sensor that can be used for weather stations or other environmental monitoring.

The board contains an EFM32ZG108 Gecko low power microcontroller and two RS232 serial ports allowing it to be daisy chained in a network. Pre-Programmed for use in an openHAB Home Automation system or can be Re-Programmed for other uses.


  • HTU21D(F) Humidity and Temperature Sensor
    • Humidity sensor
      • Range of 0-100% Relative Humidity
      • Selectable resolution of 8, 10, 11, or 12-bits
      • Measuring time is typically 2ms @ 8bits and 14ms @12-bits
    • Temperature sensor
      • Range of -40°C to +125°C
      • Selectable resolution of 11 to 14-bits
      • Accuracy of ±0.3°C
    • Fully calibrated
    • Low power consumption 450µA typical
    • Fast response time
  • +3.6V to +6V Input Voltage
  • Power management designed for very low standby power
  • Small Size: PCB is 20mm x 20mm (0.79" x 0.79")
  • EFM32ZG108 Gecko Microcontroller
    • ARM Cortex-M0+
    • Low Power Operation
    • 32KB Flash Memory
    • 4KB RAM
  • MAX3232 Dual RS232 Line Driver/Receiver
  • Two 4 Pin DF11 Right Angle Male Connectors each with Power and RS232
  • 6 Pin DF11 Right Angle Male Connector for Programming and Debug
  • Pre-Programmed with openHAB Item Firmware for Plug-and-Play
  • Pre-Programmed Firmware is Designed for Low Power Operation
  • May be Programmed with the Arduino IDE


  • Home automation
  • Environmental monitoring


Schematic: HTU21Dx2_C
Eagle Files
EFM32ZG108 Data Sheet
EFM32ZG Reference Manual
HTU21D/HPP845 Data Sheet

 Arduino IDE Examples:



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