Presence
HLK-LD2412
The LD2412 detects presence and small movements. It does not report individual X/Y positions of people.
- Module range
- Up to 9 m
- Horizontal field of view
- ±75°
- Output
- Presence, no X/Y
Everything your room knows,
tucked away in the wall
Presence, air quality and a touch button for Home Assistant in one flush-mount module.
Coming soon
Front 55 × 55 mm
Fits shallow round back boxes too
The module itself is 26 mm deep. When using Ethernet/PoE with a bare RJ45 connector without a boot, approximately 40 mm of installation depth is required. That means WallSense also fits in a shallow round back box.
- Mounts on 60 mm screw centres
- Adapter plates for well-known switch ranges
- Openings around the housing for air measurements
- Can share one frame with a switch or socket
Where does WallSense fit?
The round 60 mm box is used in the Netherlands, Belgium, Luxembourg, Germany, Austria and France, among other countries. The same box principle is also common across Central, Northern and Southern Europe; we are checking the exact fit for each country and brand.
The United Kingdom, Ireland and Denmark often use different systems. Rectangular three-module boxes are common in Italy. We are investigating separate mounting plates or housings for these markets.
Fits the switch range already in your home
The WallSense front measures 55 × 55 mm. That is the same outer size as Gira System 55 and the CeilSense front, and the smallest size on the market. It already fits Gira System 55 directly. For larger openings, we are developing adapter plates that neatly fill the extra space around the front.
| Gira, System 55 | Ready |
|---|---|
| Jung, A series, AS 500 | In development |
| Berker, S.1, B.3 | In development |
| Merten, System M | In development |
| Busch-Jaeger, Balance SI, Future Linear | In development |
| Niko, Original, Pure | In development |
Is your brand or range missing? Share it in Discord so we can include it in a future adapter plate.
Eight functions behind one front
Sensing, control and visual alerts brought together in a single flush-mount module.
- PresenceHLK-LD2412
- Sees that you are there, even when you lie still on the sofa reading. It responds to micro movements.
- PositionHLK-LD2450
- Tracks up to three people at once with their position in the room, so you can work with zones.
- CO₂Sensirion SCD41
- A real NDIR measurement, not an estimate. You see straight away when the air in the room is used up.
- VOC and NOxSensirion SGP41
- Measures volatile compounds and nitrogen oxides. Noticeable after cooking, cleaning or painting.
- Temperature and humiditySensirion SHT45
- Accurate readings at living height, exactly where you want to steer heating and ventilation.
- Ambient lightVEML7700
- Measures ambient light in lux, so lights can switch on only when the room is dark enough.
- Touch
- The capacitive touch surface appears in Home Assistant. There you link a tap to an action, scene or automation.
- Status and ambient light1 + 16 RGB
- One status LED in the front and sixteen RGB LEDs on the back of the PCB. You decide in Home Assistant how they behave; CO₂ warnings, doorbell alerts and night lighting are examples.
Two radars that complete each other
WallSense combines two radars: one for presence during small movements and one for the position of up to three people. Measurements appear in Home Assistant, where you set up your own zones and automations.
These are radar module specifications, not a guaranteed WallSense range in every room. Installation, the cover frame, obstacles and settings affect detection; range can be shorter when people sit still.
Person 1
Person 2
Person 3
Flush with the wall, facing the room
WallSense sits parallel to the wall and faces straight into the room. The sensor cannot be rotated. Choose a mounting box with a clear view of the area you want to monitor. The zones and people shown are examples.
- No camera and no image, just radar points
- Works in the dark and straight through fabric and curtains
- Sensitivity adjustable per zone through ESPHome
- With Home Assistant every reading stays inside your own network
Why two mmWave radars?
The LD2450 tracks where people are. The LD2412 adds presence detection for small movements. In Home Assistant, you combine that information with zones in your room.
- Position and movementSee where someone is moving and use that position in your automations.
- Even while sitting stillThe LD2412 detects small movements, so presence detection does not depend solely on people walking around.
- Automations for each zoneCreate a zone around the sofa or desk, for example. You decide what happens in Home Assistant.
What does WallSense see in your room?
Enter the size of your room and slide the wall box along the wall. You see right away which part of the floor each radar covers and what it reports.
How much of your floor it sees
- Sees that someone is there LD2412
- 0%
- Knows where everyone is LD2450
- 0%
Room of by m, with the sensor at m from the left corner. The presence radar sees % of the floor, the position radar %.
What it sees now
- Presence LD2412
- YesNo
- Movement LD2412
- YesNo
- Nearest person LD2412
- nobody
Positions LD2450 0 of 3
- Person presence only not seen
Seen from above. We use 80% of the Hi-Link figures: presence up to 7.2 m within ±75°, positions up to 4.8 m within ±60°. Walls, furniture and placement decide what you get at home.
Touch control for Home Assistant
The capacitive touch surface behind the front is passed to Home Assistant. There you decide what a tap does: switch a light, start a scene or trigger an automation. With no moving parts, there is no mechanical wear.
- Touch appears in Home Assistant
- Link your own action, scene or automation
- No mechanical button, so no wear
- The LED can provide visual feedback
See what you breathe
Three Sensirion sensors measure the air in the room, right at the height where you live.
- CO₂
- 400 to 5,000 ppmSCD41 with a real NDIR measurement, the reliable standard for CO₂.
- VOC and NOx
- Index 1 to 500SGP41 turns gases into an index you can automate on directly.
- Temperature
- Up to ±0.1 °CSHT45 is among the most accurate sensors in its class.
- Humidity
- Up to ±1.0 %RHUseful against mould and to drive your ventilation intelligently.
WallSense does not measure particulate matter, so PM1, PM2.5 and PM10 readings are not available. Want to measure particulate matter? See the UltimateSensor or UltimateSensor Mini with the optional SPS30 particulate matter sensor.
One RGB status LED in front, sixteen RGB LEDs behind
One RGB status LED sits in the front, with another sixteen controllable RGB LEDs on the back of the PCB. You set their colour, brightness and behaviour in Home Assistant. The uses below are examples of automations you can create yourself.
- Example: red when CO₂ is high
- Example: doorbell alert
- Example: night light for a child’s bedroom or hallway
Two ways to power WallSense
Choose PoE over an Ethernet cable or 110 to 240 V mains power. USB-C is only for flashing firmware.
-
Power over Ethernet
Power and a wired network connection over a single Ethernet cable.
- Via a PoE switch or PoE injector
- No separate power adapter at the sensor
-
110 to 240 V mains power
Power WallSense from the mains when a suitable electrical supply is available at the installation point.
- 110 to 240 V AC
- Network connection via WiFi or Ethernet
Have mains connections installed by a qualified installer. The stated installation depth of approximately 40 mm applies to the setup with an RJ45 connector without a strain-relief boot.
An ESP32-C6 at its heart
Choose WiFi 6 or wired Ethernet with PoE. The ESP32-C6 also includes an 802.15.4 radio that ESPHome can use for OpenThread.
- Ethernet + PoE
- Network and power over a single UTP cable, with no separate power adapter.
- WiFi 6
- More efficient and more stable on a busy network, also on 2.4 GHz.
- OpenThread via ESPHome
- ESPHome can use the built-in 802.15.4 radio for OpenThread.
- Bluetooth 5 LE
- For setup and for future extensions.
- USB-C
- The USB-C connection is for flashing firmware, not for powering WallSense.
Home Assistant, our app or both
Use WallSense with Home Assistant, the SmartHomeShop cloud app or both at the same time. With compatible firmware, you can combine local dashboards and automations with remote access to your readings in our app.
Locally with Home Assistant
With local ESPHome firmware, readings go straight to Home Assistant. No SmartHomeShop account or cloud subscription is required.
- Presence, climate, air quality and light level as Home Assistant entities.
- Draw your room and zones with the Room Designer and use touch controls in your automations.
Through the SmartHomeShop app
No Home Assistant needed. Open our cloud app in a browser on your phone, tablet or computer, even when you are away from home.
- View available room and presence readings remotely.
- Follow your readings and available history in the app.
- Use WallSense through your SmartHomeShop account, without a Home Assistant installation.
Cloud use requires an account, internet and cloud firmware that supports your model. Readings and features depend on hardware and firmware; history and usage limits depend on your app plan. With supported firmware, you can also use the app and Home Assistant together.
Find the right firmwareSee WallSense in action
Switch between the floor plan, 3D room and radar. See people move between zones and explore the measurements on your dashboard.
Interactive demonstration with simulated people and sample readings, not live data from a WallSense. The room score is illustrative only.
Sample data
👤
Drag to rotate
Zone 1
Zone 2
Entry
Refresh: 10 Hz
Range: 0 to 6 mField of view: 120°
°C
%
CO₂
CO₂
ppm
lx
CO₂
CO₂ Quality
400
800
1200
1600
2000
VOC / NOx
SGP41VOC-index
NOx-index
Status and ambient light 1 + 16 RGB
One status LED and sixteen RGB LEDs. You decide what they do in Home Assistant, such as a CO₂ alert, doorbell notification or night light.
Draw your room, add doors and furniture, and mark where WallSense is mounted. Then create zones around your sofa or desk. The animation shows how this works in the SmartHomeShop panel.
Click a step
Room Designer
Step
Coming to the SmartHomeShop app
No Home Assistant? We are bringing WallSense to our app, just like the UltimateSensor. You will then see in the browser on your phone, tablet or computer how the air in your room is and whether someone is there.
Coming soon. WallSense is not in the app yet, this example follows the UltimateSensor.
Sample data
Room Quality
Good7.4
Good
Ventilation recommendedCO₂ is rising. Open a window or turn up the ventilation.
- CO₂
- 1,050 ppm
- Poor
- Temperature
- 22.4 °C
- Humidity
- 52 %
- Light
- 180 lux
- VOC Index
- 120
- NOx Index
- 1
- Presence
- Occupied
- 2 persons
CO₂ quality
Sample data
Trends
30 days- Average CO₂
- 612 ppm
- Average temperature
- 21.2 °C
- Avg. humidity
- 52%
CO₂ per hour
Average ppm per hour of the day
Temperature and humidity per hour
Sample data
96
Overall climate score
Very comfortable
166 measurement hours · 99% coverage
- Room comfort
- 98
- Air freshness
- 93
Latest measurement hour · today 20:00
- CO₂940 ppm
- Temperature22.3 °C
- Humidity51%
- VOC115
CO₂ and ventilation
Target 950 ppm- Average
- 623 ppm
- Highest value
- 1,050 ppm
- of hours under 950 ppm
- 98%
Climate remains stable All goodTemperature and humidity stayed within the comfort band this week.
Sample data
Alerts
-
High CO₂High CO₂ concentration
> 1,000 ppm
Last triggered: today 20:24
-
High VOCHigh VOC index
> 250
Not triggered yet
-
Device offline
> 5 min
Not triggered yet
-
Recent activity
High CO₂: 1,024 ppm (> 1,000 ppm)
High CO₂: 1,124 ppm (> 1,000 ppm)
What the email looks like
SmartHomeShop.ioHigh CO₂ - Living room
High CO₂
An alert was triggered on your device Living room.
Measured value: 1,024 ppm
Threshold: > 1,000 ppm
Quick presets
- High CO₂> 1,000 ppm
- High VOC> 250
- Frost alarm< 3 °C
- Heat alarm> 35 °C
- Device offline> 5 min
Send via
- Push notifications Coming soon
- A room score out of 10 from CO₂, VOC, temperature and humidity, with advice
- CO₂ in five levels, from Excellent to Unhealthy, on a colour bar from 400 to 2,000 ppm
- Presence and the number of people from the radars
- Live graphs, and looking back per day, week, month or year
- Average CO₂ per hour of the day, with guide lines at 800 and 1,200 ppm
- Temperature, humidity, light and presence per hour
- CO₂ per day of the week as well
- Pick a week, 30 days, this or last month, this year or your own dates
- One climate score from 0 to 100: room comfort counts 60%, air freshness 40%
- A comfort band per season, at 40 to 60% humidity
- CO₂ as a measure of ventilation, with a target of 950 ppm
- Over 24 hours, 7 days or 30 days, with advice
- Presets for CO₂ above 1,000 ppm, VOC, frost, heat and device offline
- Rules for humidity, light and NOx too
- The app checks every minute and emails in Dutch, English or German
- Free: 1 alert per device. Plus gives you 20, Pro unlimited.
Radar specifications
HLK-LD2412
- Module range
- Up to 9 m
- Horizontal field of view
- ±75°
- Output
- Presence, no X/Y
- Frequency
- 24 GHz
- Configuration
- Sensitivity per distance gate
HLK-LD2450
- Module range
- Up to 6 m
- Horizontal field of view
- ±60°
- Output
- Up to 3 people, X/Y
- Frequency
- 24 GHz
- Configuration
- 3 rectangular radar zones
WallSense sits parallel to the wall and faces straight into the room. The sensor cannot be rotated. Choose a mounting box with a clear view of the area you want to monitor. The zones and people shown are examples.