Wi-Fi HaLow Connectivity for Tasmota IoT Devices

This bachelor thesis investigated how a Wi-Fi HaLow module can be connected to an ESP32-C3 microcontroller and how such a solution could be integrated into Tasmota.

Prototype setup with ESP32-C3 and Murata Type 2HL module

Initial situation

Wi-Fi HaLow, also known as IEEE 802.11ah, is a sub-GHz Wi-Fi technology designed for long-range and low-power communication. It is interesting for IoT devices that need IP-based connectivity but are installed in locations where conventional Wi-Fi coverage is weak, for example in basements, meter cabinets or technical rooms.

The project partner was Gantrisch Energie AG which offer the gPlug product family. The selected Wi-Fi HaLow hardware was the Murata Type 2HL module, which is based on the Newracom NRC7394 chipset. The target platform was an ESP32-C3 microcontroller running a Tasmota IoT firmware.

Problem statement / Project goal

The main challenge was that Tasmota does not natively support the selected Wi-Fi HaLow module. The preferred approach was to use the Murata module in host mode and integrate it as a normal network interface. During the project, this approach turned out to be too complex for the ESP32-C3 target because the available host-mode software depends strongly on a Linux host environment.

As a fallback, the project investigated the standalone firmware of the NRC7394. In this mode, the Wi-Fi HaLow module handles networking internally, while the ESP32-C3 controls it with AT commands over SPI. The goal was therefore to build a working proof of concept and to document a feasible path toward a Tasmota and gPlug integration.

Solution developed and its benefits

The final result is an ESP32-C3 proof of concept for controlling the Murata Type 2HL module in standalone AT-command mode. The prototype can scan for a Wi-Fi HaLow access point, connect to a HaLowLink 2, obtain an IP address and transmit UDP payload data.

• Verified the Murata Type 2HL hardware and Wi-Fi HaLow connectivity in reference setups.
• Evaluated the Newracom host-mode and standalone software approaches.
• Built and flashed standalone AT-command firmware for the NRC7394.
• Ported the ATCMD_HSPI host concept to an ESP32-C3 prototype.
• Implemented SPI, HSPI, AT-command handling and UDP measurement commands.
• Measured application-level UDP payload transmission in indoor and outdoor scenarios.
• Documented limitations and a realistic future integration path for Tasmota and gPlug.

The project outcome was not a finished Tasmota integration. Instead, it provides a practical foundation for a future Tasmota driver that could provide Wi-Fi HaLow control.

Results

The prototype successfully demonstrated that an ESP32-C3 can control the Murata Type 2HL module over SPI and use it for Wi-Fi HaLow communication. Stable UDP payload transmission was achieved in short-range and selected indoor scenarios. The measured throughput was approximately 0.131 Mbit/s in the implemented measurement setup. This value should be interpreted as application-level prototype throughput, not as the maximum Wi-Fi HaLow throughput.

Key terms

• Wi-Fi HaLowSub-GHz Wi-Fi technology for long-range and low-power communication.
• IEEE 802.11ahThe specification for Wi-Fi HaLow.
• ESP32-C3The microcontroller used as the host platform.
• TasmotaThe target IoT firmware environment.
• Murata Type 2HLThe Wi-Fi HaLow module used in the project.
• NRC7394The Newracom Wi-Fi HaLow chipset inside the Murata Type 2HL module.
• AT commandsText-based commands used by the ESP32-C3 to control the Wi-Fi HaLow module.
• SPIThe host interface used between the ESP32-C3 and the Murata Type 2HL module.
• IoTInternet of Things: Embedded systems and devices communicating over the internet or local networks..
• gPlugAn IoT adapter product family by Gantrisch Energie AG for Swiss smart-meter customer interfaces.

Customer

Gantrisch Energie AG
Hermann Hüni
Im Than 7
3150 Schwarzenburg
Gantrisch Energie AG
gPlug

Team