Sensy-One S1 Pro Multi Sense mmWave Multisensor | Zigbee Version

Looking for the Wi-Fi / ESPHome version? Check out the Sensy-One S1 Pro Multi Sense (Wi-Fi version) here.

Multifunctional Presence and Air Quality Sensor for Home Assistant (Zigbee)

The Sensy-One S1 Pro Multi Sense (Zigbee Version) is an advanced presence and environmental sensor, specially developed for Home Assistant. This compact sensor combines real-time mmWave presence detection via the Hi-Link LD2450 radar module with extensive air quality measurement, ambient light measurement, an RGB status light, and a built-in buzzer for alerts. Thanks to the native Zigbee protocol, the sensor integrates locally and seamlessly into Home Assistant via ZHA or Zigbee2MQTT, without requiring Wi-Fi credentials, cloud accounts, or ESPHome configurations.

Connectivity and Protocols

The S1 Pro Zigbee is powered by the powerful ESP32-C6 microcontroller (32-bit RISC-V single-core processor) with native 2.4 GHz IEEE 802.15.4 Zigbee connectivity. The sensor connects directly to your Zigbee coordinator and operates locally via ZHA (with the included Sensy-One custom quirk) or Zigbee2MQTT. The device is designed as a Zigbee End Device (does not act as a router/repeater) with minimal network load, ensuring your Zigbee network performs optimally.

Platform Compatibility

Fully optimized for Home Assistant via ZHA and Zigbee2MQTT. The S1 Pro Zigbee is primarily intended for HA users and offers full support for the official Sensy-One Zone Editor integration with Heatmap functionality. All sensor data and controls remain 100% local within your own network.

Power Supply and Energy

The sensor operates on 5V USB-C and has a standard USB-C port at the bottom for cable mounting. Optionally, you can use the S1 Pro Female USB-C Add-on to place the sensor upright on a cabinet or desk, or the S1 Pro Male USB-C Add-on to connect directly to a wall adapter without a cable.

mmWave Presence Detection

The Hi-Link LD2450 radar module offers 24 GHz mmWave detection with an adjustable range of 20 cm to 6 meters, a horizontal field of view of 120°, and a vertical range of approximately 70°. The sensor detects up to three people simultaneously and reports their exact position (in cm), distance, and movement speed (in cm/s) every 0.5 seconds to Home Assistant. You can set up 3 polygon detection zones and 1 polygon exclusion zone (with a maximum of 8 points per polygon). Each zone has adjustable presence delays and motion thresholds, and supports both single-target and multi-target modes.

Air Quality with Bosch BME688

The built-in Bosch BME688 sensor measures estimated CO₂ level (eCO₂), estimated VOC level (volatile organic compounds), air quality index (IAQ, from 0 to 500), gas resistance (in kΩ), temperature, humidity, and atmospheric pressure. The sensor provides early insight into changes in indoor air, allowing automations to intervene before comfort or concentration decreases. The temperature offset is easily adjustable via software.

Optional CO₂ Sensor (SCD40 Add-on)

For applications requiring absolute accuracy, the S1 Pro supports the optional S1 Pro CO₂ Add-on with the Sensirion SCD40 module. This NDIR sensor measures true CO₂ concentrations (up to 40,000 ppm) and connects directly to the S1 Pro PCB without soldering. The SCD40 also supports forced calibration and factory settings directly from Home Assistant.

Automatic Sensor Compensation

The S1 Pro sensor can be easily provided with a temperature offset from Home Assistant to adjust measurements to specific placement or environmental conditions. The BME688 and the optional SCD40 module can thus be perfectly calibrated for consistent measurement results.

Ambient Light Sensing

Integrated ambient light measurement via the Lite-On LTR-381RGB-01 sensor measures the current light intensity in Lux. This allows lighting and shading automations to react naturally to changing daylight and cloud cover based on actual light values instead of fixed schedules.

Visual and Audible Feedback

A built-in WS2812 RGB-LED and an MLT8530 piezo buzzer provide immediate visual and clear audible feedback. If the Zigbee connection is lost, the LED gives a purple "breathing" signal. After reconnection, the stored status is automatically restored. All feedback can be fully controlled via Home Assistant automations, from subtle status indicators to clear alarms.

Physical and Installation

The housing is made of high-quality resin and specifically designed for minimal interference with mmWave signals, passive cooling, and optimal airflow past the environmental sensors.
Dimensions: 50 mm high, 35 mm wide, 25 mm deep.
The sensor has a standard USB-C port at the bottom and internal connectors for expansion with CO₂ and USB-C add-ons.

Mounting Options (Add-ons)

The S1 Pro supports various optional mounting adapters for flexible placement. With the S1 Pro Corner Ball Mount Add-on, you can precisely position the sensor in 90-degree corners, while the S1 Pro Standard Ball Mount Add-on allows for sleek mounting on any wall surface. For standing placement on a desk or dresser, use the S1 Pro Female USB-C Add-on. The S1 Pro Male USB-C Add-on allows direct connection to a wall adapter. For true CO₂ measurements, simply snap on the S1 Pro CO₂ Add-on.

Software and Updates

No ESPHome knowledge or Wi-Fi setup is required. For ZHA users, Sensy-One provides a custom quirk for seamless operation in Home Assistant. With the Sensy-One Zone Editor Add-on, you can also create interactive 2D and 3D floor plans, track live targets, analyze spatial heatmaps, and draw detection and exclusion zones. Any firmware updates and recovery can be easily performed via USB.

Environment and Durability

Intended for indoor use in standard living and working spaces. The high-quality resin housing is durable and provides excellent heat dissipation. Not suitable for damp or very dusty environments such as bathrooms or workshops without additional protection.

Performance and Zigbee Network Load

The sensor is specifically designed for minimal Zigbee network load, even with active multi-target tracking. The average network load remains well below 1% (based on the 250 kbit/s IEEE 802.15.4 Zigbee data rate):

• Quiet room: approx. 0.04% load
• Normal tracking of 1 person: approx. 0.46% – 0.65% load
• Busy activity with multiple people: approx. 1.10% load
• Maximum continuous load: approx. 1.80% load
• Short peak load during bursts: max. approx. 5.15%

This leaves more than enough capacity for your other Zigbee devices in the network.

Air Quality Index (IAQ) Classification

The BME688 provides an air quality index (IAQ) that offers real-time insight into the indoor climate. The index provides clear, human-readable IAQ values and classifications in Home Assistant. The sensor detects VOCs from cooking fumes, cleaning products, off-gassing from furniture, and human presence, allowing ventilation systems to activate in a timely manner.

Safety and Privacy

The sensor operates 100% locally via Zigbee. No data is sent to the cloud, and the sensor does not require Wi-Fi network passwords or external accounts. Your privacy is fully guaranteed.

Package Contents

Standard delivery includes the S1 Pro Multi Sense Zigbee edition consisting of:

• S1 Pro Multi Sense PCB (ESP32-C6)
• S1 Pro Multi Sense housing (Resin)
• Hi-Link LD2450 mmWave radar module
• ESD-safe packaging

* Optional add-ons (such as the CO₂ sensor, ball mounts, and USB-C adapters) are sold separately. A USB-C power cable and 5V adapter are not included.

Use Cases

The S1 Pro Zigbee is ideal for Home Assistant users who have based their smart home on Zigbee and want reliable presence detection without burdening the Wi-Fi network. Thanks to mmWave technology, the sensor detects people even when they are stationary (e.g., on the couch or behind a desk). Perfect for controlling lighting, climate control, and monitoring indoor climate via ZHA or Zigbee2MQTT.

Pros

• Native Zigbee connectivity (ZHA and Zigbee2MQTT) via powerful ESP32-C6 RISC-V processor
• Extremely low Zigbee network load (typically <1%), leaving ample capacity for other devices
• Advanced mmWave detection (LD2450) with tracking of 3 people, position/speed, and 4 configurable zones
• 100% local: no Wi-Fi settings, cloud account, or ESPHome required
• Bosch BME688 environmental sensor for eCO₂, VOC, IAQ, temperature, humidity, and atmospheric pressure
• Optional NDIR CO₂ sensor (SCD40 add-on) easily connectable without soldering
• Fully compatible with the Sensy-One Zone Editor Add-on for 2D/3D visualization and heatmaps
• RGB status LED and piezo buzzer for configurable visual and audible notifications

Cons

• Operates as a Zigbee End Device; does not act as a Zigbee router/repeater to extend the network
• Requires a suitable Zigbee coordinator (such as Sonoff, SkyConnect, Zigate, etc.) connected to Home Assistant

Manual and Support

• Find documentation and manual here (GitHub)
• Sensy-One Zone Editor Home Assistant Add-on
• Need support? The Sensy-One team is active on Discord and happy to help!

Frequently Asked Questions

Does the S1 Pro Multi Sense Zigbee work with Home Assistant?

Yes, the sensor is designed for Home Assistant and works via ZHA (with the included custom quirk) or via Zigbee2MQTT. After putting the sensor in pairing mode, it will be immediately recognized by your Zigbee network.

How do I pair and install the Zigbee sensor?

Connect the sensor to a 5V USB-C power supply. When the sensor is not connected to a Zigbee network, the built-in RGB-LED will emit a purple breathing light. Put your Zigbee coordinator in Home Assistant (ZHA or Zigbee2MQTT) into pairing mode to add the device. For zone configuration, you can use the Sensy-One Zone Editor add-on.

Which network protocol does this version of the S1 Pro use?

This version uses Zigbee (IEEE 802.15.4 at 2.4 GHz) via the ESP32-C6 chip. Are you looking for the Wi-Fi / ESPHome variant? Then check out the S1 Pro Wi-Fi version.

Does the S1 Pro Zigbee act as a Zigbee Router or Repeater?

No, the S1 Pro Zigbee is designed as a Zigbee End Device and does not act as a router/repeater. This was deliberately done to keep the network impact minimal and prevent interference.

Doesn't continuous mmWave tracking burden my Zigbee network too much?

No, the device is optimized for extremely low network impact. Even with heavy multi-target tracking, the network load remains around 1.10% (with a continuous maximum of 1.80%). This leaves more than enough capacity for your other Zigbee sensors and lights.

What is the range of the mmWave sensor?

The Hi-Link LD2450 radar module has an adjustable range of 20 cm to 6 meters, with a horizontal field of view of 120° and a vertical range of approximately 70°. It can track up to 3 people simultaneously and reports position and speed every 0.5 seconds.

What is the difference between the BME688 and the optional SCD40 CO₂ sensor?

The BME688 calculates an estimated CO₂ value (eCO₂) based on VOC (volatile organic compound) measurements, which is ideal for general air quality indication. The SCD40 (optional add-on) uses NDIR technology for true CO₂ measurements up to 40,000 ppm, which is perfect for spaces where exact CO₂ values are crucial (such as bedrooms and offices).

Which add-ons are available for the S1 Pro Zigbee?

There are five modular add-ons available: the S1 Pro CO₂ Add-on (Sensirion SCD40), S1 Pro Female USB-C Add-on (for standing placement), S1 Pro Male USB-C Add-on (for direct plug-in to a power adapter), S1 Pro Standard Ball Mount Add-on (for wall mounting), and S1 Pro Corner Ball Mount Add-on (for corner mounting). All add-ons are plug-and-play and do not require soldering.

How do I update the firmware of the Zigbee sensor?

Firmware updates and any recovery are performed via a USB-C connection to your computer. Consult the official GitHub repository of the S1 Pro Zigbee for the latest firmware files and instructions.