Omnimo nRF52840 in Home Automation

If you’re looking to dip your toes into the world of Zigbee development, this project is for you. In this tutorial, we’ll guide you through building a wireless temperature and humidity sensor using the Omnimo nRF52840 dev board paired with the Temp&Hum 24 Click (HDC3021 Sensor). The sensor data will be broadcast over Zigbee and integrated into Home Assistant using the ZHA (Zigbee Home Automation) integration.

What You’ll Need

Hardware

Omnimo nRF52840 Dev BoardA compact, powerful development board based on the Nordic Semiconductor nRF52840 SoC, featuring Bluetooth Low Energy (BLE) and Zigbee capabilities.

TEMP&HUM 24 CLICKA MikroElektronika Click board equipped with the HDC3021 sensor, capable of measuring temperature and humidity with high accuracy.

Segger J-Link Programmer or another way to program nRF52840 chip

Software Tools

nRF5 SDK for Thread and Zigbee v4.2.0The official Nordic SDK that provides the tools and libraries needed to develop Zigbee applications.

Segger Embedded Studio for ARM (V7.32a)The IDE used for compiling and flashing the firmware.

Githttps://github.com/OmarEMbed/Omnimo-nRF52840-zigbee-temperature-humidity-sensor

Home Assistant with the ZHA integration enabled

Step 1: Set Up Your Development Environment

Download the SDK

Head over to Nordic’s website and download the nRF5 SDK for Thread and Zigbee v4.2.0. Extract it to a directory of your choice.

Install Segger Embedded Studio

Download and install Segger Embedded Studio for ARM (V7.32a) from the official website.

Clone the Project Repository

Navigate to the examples/zigbee/experimental folder in the extracted SDK directory and clone this project repository https://github.com/OmarEMbed/Omnimo-nRF52840-zigbee-temperature-humidity-sensor into it.

Step 2: Understand the Code

Read Sensor Data

The HDC3021 sensor on the Temp&Hum 24 Click measures temperature and humidity. The code interfaces with the sensor via TWI to retrieve these readings.

Broadcast Data Over Zigbee

Using the nRF52840’s Zigbee stack, the sensor data is packaged and transmitted wirelessly to a Zigbee coordinator (e.g., your Home Assistant setup with ZHA).

Step 3: Compile and Flash the Firmware

Open the Project

Launch Segger Embedded Studio and open the.emProject file located in project directory cloned from https://github.com/OmarEMbed/Omnimo-nRF52840-zigbee-temperature-humidity-sensor

Build the Project

Click the Build button to compile the code. Ensure there are no errors during compilation.

Flash the Firmware

Connect your Omnimo nRF52840 board to your computer using a Segger J-Link programmer.

Step 4: Integrate with Home Assistant

Enable ZHA Integration

If you haven’t already, enable the Zigbee Home Automation (ZHA) integration in Home Assistant. Follow the official ZHA setup guide if needed.

Pair the Sensor

• Power the Omnimo nRF52840 board using USB Type-C or Battery
• Put your Zigbee coordinator into pairing mode.
• Reset the Omnimo nRF52840 board to initiate pairing.
• Once paired, the sensor should appear in Home Assistant under the Devices section.

Verify Data

Check the Temperature and Humidity entities created by the sensor. You should see real-time readings from the TEMP&HUM 24 CLICK sensor.