Sonoff Zigbee Indoor Siren SNZB-09P

Product detailed description

Sonoff SenseGuard SNZB-09P Zigbee alarm siren: loud alarm and quiet reminder in one

Sonoff SNZB-09P (SenseGuard Indoor Siren) is a smart indoor siren with Zigbee 3.0 that turns your door, motion or water leak sensors into a fully fledged home alarm. When a sensor detects a problem, the siren sounds at up to 105 dB, flashes its red light ring, or does both at once.

Unlike classic sirens, it does not always scream the same way. You set the volume, tone, alarm duration and light in the app separately for each situation, so the same device can scare off a burglar one day and gently remind you of an open window the next. It requires a compatible Zigbee gateway, for example the Sonoff Zigbee Bridge PRO.

105 dB you can hear across the whole floor

At maximum volume, the Zigbee siren reaches 105 dB at a distance of 1 m, easily covering an entire floor of a flat or house, deterring intruders and waking even heavy sleepers. If you do not need full power, three more levels are available: approximately 75, 82 and 93 dB. The lower levels suit notifications where you do not want to wake the whole house.

10 tones and a red light alarm

The siren has 10 built-in alarm tones. You can assign a different one to each sensor, so the sound alone tells you whether the front door opened or water is leaking in the bathroom. Custom sound files cannot be uploaded; the choice is limited to the built-in tones.

On the front there is a red light ring that can be controlled independently of the sound. Choose sound only, flashing light only, or both. The light alarm is useful in the dark, in noisy environments, or at night when you do not want to wake a child but need to see that something is happening. Alarm duration can be set from 1 second up to 15 minutes.

USB-C power with backup battery

Main power is supplied via USB-C 5 V / 1 A. Inside there is also a 600 mAh lithium battery: during a power cut the siren automatically switches to battery and stays online, which matters for security because burglars switch off circuit breakers more often than you might think. When power returns, the battery recharges automatically. According to the manufacturer, it lasts more than 300 days on battery in silent mode, so you can place it even where there is no socket.

Automations with sensors and cameras

The real power of a smart siren shows in automations. Pair it, for example, with the SNZB-04PR2 door and window sensor, SNZB-03PR2 PIR motion sensor or the SNZB-05P water leak sensor and set a different action for each event: full volume and a sharp tone for an intrusion, a quiet tone for an open window. The siren also reports its own status: USB power disconnection, loss of connection and sabotage, i.e. tamper detection when removed from its mount. These events can also trigger a notification on your phone.

The same siren also works as a home doorbell or reminder. At low volume and with a soft tone it lets you know that the washing machine has finished, someone rang at the gate or the fridge was left open.

Installation is simple: attach the removable mount to the wall with screws or 3M double-sided tape, with no changes to your electrical wiring. A short press of the pairing button also lets you check whether the siren is within range of the gateway or a Zigbee router. You will find the full range of Zigbee products in our shop.

Who is the SNZB-09P siren for

• Owners of a Sonoff Zigbee gateway or NSPanel Pro who want to add a real alarm to their sensors.
• Users of Home Assistant with Zigbee2MQTT or ZHA building their own alarm system without monthly fees.
• Tenants and flats where you do not want to drill or run cables.
• Small businesses, storerooms and garages that need an affordable, loud indoor siren.
• Households that want audible alerts for water leaks, open windows or finished appliances.

Use cases

• Alarm when a door opens at night: when the house is armed and the door sensor reports opening, the siren sounds 105 dB and turns on the red light.
• Water leak warning: a sensor under the washing machine or boiler triggers a specific tone, so you know straight away where to run. 💧
• Siren for a Home Assistant alarm panel: controlled via Zigbee2MQTT as part of an alarm with home/away/night modes.
• Silent light alarm: flashing only, without sound, for example when a child is asleep or for a hard-of-hearing family member.
• Gate doorbell: a button or sensor at the gate triggers a soft tone at low volume.
• Garage or workshop alarm: a motion sensor triggers the alarm outside working hours, even during a power cut.

Key features

• Volume up to 105 dB: 4 levels, approximately 75 / 82 / 93 / 105 dB at 1 m.
• 10 built-in tones: assign a different sound to each sensor or event.
• Red light ring: controllable independently of the sound.
• Adjustable alarm duration: from 1 second up to 15 minutes.
• 600 mAh backup battery: automatic switchover during a power cut and more than 300 days in silent mode.
• Tamper detection: alerts you when someone removes the siren from its mount.
• Power monitoring: reports USB power disconnection and battery level.
• Zigbee 3.0 with up to 100 m range: in open space, with a range check via the button.
• OTA updates: update the firmware via eWeLink or Home Assistant.

Technical specifications

Protocols and compatibility

• Zigbee 3.0 (IEEE 802.15.4): the siren requires a Zigbee gateway or coordinator; it does not work on its own over Wi-Fi.
• Sonoff gateways (eWeLink): the manufacturer recommends Zigbee Bridge PRO, Zigbee Bridge Ultra, NSPanel Pro and iHost. The eWeLink app gives you all features, including tones, volume, alarm duration and history.
• Home Assistant + Zigbee2MQTT: full support according to the manufacturer (sound, light, tone, volume, duration, battery, tamper, OTA), for example with the Sonoff Dongle Plus MG24.
• Home Assistant ZHA: native support has not yet been merged into ZHA (PR #5136 is awaiting approval). For all features you currently need to add a quirk script following the guide in the Sonoff Help Center.
• Samsung SmartThings: works with the Aeotec Smart Home Hub V3 and a driver from Sonoff; OTA updates are not supported here.
• Amazon Alexa and Google Home: alarm on/off only, via the eWeLink cloud integration.
• IFTTT: alarm on/off, requires an eWeLink subscription.

Why choose the Sonoff SNZB-09P

• One siren for everything: from a 105 dB alarm to a quiet doorbell, just change the automation settings.
• Works without mains power: the backup battery keeps the alarm online when someone switches off the breaker.
• Open platform: eWeLink, Home Assistant and SmartThings, with no mandatory monthly fees.
• Fits the Sonoff ecosystem: the same app and gateway as your Sonoff SenseGuard sensors.

You will find more sirens, locks and home security accessories in the category Entrance security.

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