Getting started with SONOFF Dongle Plus MG24 Zigbee adapter using Home Assistant

We have received a sample of the SONOFF Dongle Plus MG24 (also known as Dongle-PMG24) Zigbee/Thread USB dongle for review. As its name implies, it’s based on a Silicon Labs EFR32MG24 wireless chip, and the company claims up to 200 meters range thanks to an included 3dBi antenna.

It is compatible with Windows, Linux, macOS, Raspberry Pi OS, and other operating systems that support USB serial drivers. The dongle works seamlessly with popular open-source platforms, such as Home Assistant, Zigbee2MQTT, ioBroker, and OpenHAB.

In this review, we will go through an unboxing of the SONOFF Dongle Plus MG24, before connecting it to a Raspberry Pi 4 running Home Assistant. We will use two Zigbee devices from SONOFF: the  AirGuard TH (SNZB-02DR2) temperature and humidity sensor with an LCD, and the MINI DUO-L (MINI-ZB2GS-L) dual-channel/2-gang Zigbee 3.0 switch to demonstrate how to use the dongle with Home Assistant.

SONOFF Dongle Plus MG24 unboxing

The packaging clearly indicates that it is the SONOFF Dongle Plus MG24 Zigbee/Thread USB dongle supporting Home Assistant and Zigbee2MQTT.

The back of the box displays a concise summary of the specifications for the Zigbee/Thread USB Dongle /  Zigbee Gateway.

The SONOFF Dongle Plus MG24 ships with a 1-meter USB extension cable, a Quick Start Guide, and a note about the antenna.

You’ll need to connect it to a device with a spare USB port that outputs at least 5V/500 mA, which should be the case for most devices.

The external antenna can be rotated up to a maximum of 180°. The manufacturer recommends not forcing it beyond this range to prevent damage to the connector.

Adding the SONOFF Dongle Plus MG24 to Home Assistant

We’ve connected the dongle to a Raspberry Pi 4 running a recent version of Home Assistant.

Now we can go to the Home Assistant dashboard to add the Dongle Plus MG24 device, going to Settings → Devices & Services → Zigbee Home Automation (ZHA). It’s just that easy. For more details, refer to the online manual.

We can enter the SONOFF Dongle Plus MG24 page to check a few details.

We are now ready to add Zigbee sub-devices.

Using the SONOFF Dongle Plus MG24 with SONOFF AirGuard TH on Home Assistant

The first Zigbee device used for testing is the SONOFF AirGuard TH (SNZB-02DR2) Zigbee temperature and humidity sensor equipped with the TLSR8656F512ET32 MCU. It features a 3.6-inch LCD screen that displays real-time temperature and humidity values, along with the highest and lowest readings over the past 24 hours, all shown on a single screen. We would have preferred a model with a PM2.5/PM10 particle sensor, which the SONOFF AirGuard PM2.5/PM10 (SAWF-07P) offers, but it connects through Matter over Wi-Fi, instead of Zigbee.

First, insert two AAA batteries for power. Then, press and hold the button on the sensor for about 5 seconds to enter Pairing mode. The screen will display the pairing icon symbol.

We can now go to the Zigbee Home Automation (ZHA) integration in Home Assistant and click Add device. The system will search and add the SNZB-02DR2 automatically.

Once thedevice is successfully added, you will see information in the Sensors (Humidity and Temperature), Configuration, and Diagnostic (Battery level…) sections.

In the Diagnostic section, we can also enable two more entities: RSSI (Received Signal Strength Indicator) and LQI (Link Quality Indicator) to evaluate the quality and strength of the Zigbee signal.

The screenshot above is when the Zigbee sensor is close to the Raspberry Pi 4 / Dongle Plus MG24 with maxed out LQI (255) and high RSSI. We walk around the house and in the street to estimate the range. The limit we got with the SNZB-02DR2 is approximately 40 meters away.

The last RSSI value before losing the signal was -103 dBm, and LQI dropped to 0.

The connection symbol disappears from the SNZB-02DR2 display, and the connection will only be restored after a few minutes. The photo below was taken inside the house within range of the Home Assistant gateway, but the connectivity had yet to be restored.

There’s nothing special to do at this point, and the Zigbee system will automatically reconnect within a few minutes.

Installation and connection of the SONOFF MINI DUO-L Zigbee switch to Home Assistant

The second Zigbee device we tested is the SONOFF MINI DUO-L (MINI-ZB2GS-L) Zigbee 3.0 2-gang switch based on a Silicon Labs EFR32MG22 MCU. It features an ultra-compact design and does not require a neutral wire. It is specifically designed to fit perfectly into standard wall switch boxes and supports a maximum total load of 12A.

The first step is to install the MINI-ZB2GS-L inside a wall electrical box where a single or dual-switch box was present. We’ll connect each switch to the S1 or S2 terminal and a L input, the live wire from the light(s) to the remaining L inputs, and finally the wires from the loads (light bulbs) to the L1 or L2 terminal to control two separate lighting circuits independently.

We had a single switch, so we only connected S1, L1, one L, and L1 terminals. If goes without saying that all that was done with the 220V mains turned off with the breaker down in our electrical box. In some countries, this may be illegal, or at least void your warranty, to do the wiring by yourself, and the installation must be made by a qualified electrician.

You should see the Green LED blink at this point. It was blinking fast in our case, so we pressed and held the button to next it for 5 seconds using an insulated screwdriver to enter Pairing mode, at which point the LED will flash slowly.

We can now go to the Home Assistant dashboard and navigate Settings → Devices & Services → select Zigbee Home Automation (ZHA) and click Add device to start searching for devices, and the MINI-ZB2GS-L will be detected within seconds.

The MINI-ZB2GS-L switch will show on the Zigbee Home Automation (ZHA) page along with the dongle and temperature/humidity sensor.

We can control either switch to turn the lights on/off through the Controls section.

Two Opening entities are also added to the Sensors section. These are supposed to report the physical switch status, but they are always stuck in Closed mode. Finally, the Configuration section allows the user to set up the start behavior of each switch.

Conclusion

It was our first time using Home Assistant with Zigbee, and we found the SONOFF Dongle Plus MG24 to be easy to use with a Raspberry Pi 4 running Home Assistant. The device proved to be a stable Zigbee coordinator for the two Zigbee devices we tested it with.

Both the SONOFF AirGuard TH (SNZB-02DR2) Zigbee temperature and humidity sensor and MINI DUO-L (MINI-ZB2GS-L), a Zigbee 3.0 dual-channel switch where automatically detected using the ZHA integration. The former reported temperature, humidity, battery level, and RSSI/LQI signal strength/quality information. We used to evaluate the range to about 40 meters. The AirGuard TH looks battery efficient since the battery level is still reported to be 100% after several weeks. We can control the MINI DUO-L switch from the Home Assistant dashboard or app, and directly from the physical light switch, and the On/Off status is updated in real-time. What’s not working are the “Opening” entities, which are supposed to report the status of the physical light switches, but they are stuck in Closed mode at all times.

Overall, the SONOFF Dongle Plus MG24 is a high-performance, easy-to-use Zigbee USB dongle that fully supports the popular Home Assistant open-source home automation platform. It is ideal for users who want to build or expand a long-term Zigbee-based smart home system.

We’d like to thank SONOFF for providing these new Zigbee devices for review. You can purchase the Dongle Plus MG24 for $32.90, the AirGuard TH for $14.90, and the MINI DUO-Lfor $21.90, and even less if you use the coupon code “cnxsoft” to get a 10% discount. Alternatively, you’ll also find the Dongle Plus M24 on the company’s Amazon store for $35.90, as well as the AirGuard TH ($14.90) and MINI DUO-L ($21.90).

CNXSoft: This article is a translation – with some additional insights – of the original review on CNX Software Thailand by Suthinee Kaerdkaew.

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