Calibration

Every room is different. Ceiling height, furniture, airflow and, when recessed, the space above the ceiling all affect the readings. This page shows per sensor what you will be able to adjust and how to make a good comparison.

Planned behavior. The firmware for CeilSense Pro is not written yet. The settings on this page follow an earlier prototype and can still change at release.

What You Can Adjust

How to Make a Good Comparison

• Wait at least 30 minutes after a start. The first SCD41 readings are not meaningful.
• Turn the LED ring off, so its heat and light do not play a part.
• Keep conditions stable: no open windows, no direct sun and no heating that just switched on.
• Use a reliable reference at the height of the sensor, not at desk height.
• Compare several readings over time, not a single value.

Radar: LD2412 + LD2450

Tune the LD2412 first. Move on to the LD2450 zones once Presence behaves well.

Dynamic Background Correction

This teaches the LD2412 what the empty room looks like. Run it after installation and when presence stays on in an empty room.

1. Empty the room: no people, no pets.
2. Stop moving objects such as fans and curtains.
3. Open the device page in Home Assistant.
4. Press LD2412 Start Dynamic Background Correction. You find it under Diagnostic.
5. Leave the room and wait until LD2412 Dynamic Background Correction is off again.

Important: If someone is in the room during the correction, the radar can learn that person as background.

Presence Timeout

LD2412 Presence Timeout and LD2450 Presence Timeout set how many seconds presence stays on after the last detection. Raise the timeout if presence drops out while someone sits still. Lower it if the room should read as empty sooner.

Distance Gates

The LD2412 divides its range into gates. At the default resolution of 0.75 m, each gate covers about 0.75 m, counted from the sensor and not across the floor.

• LD2412 Maximum Distance Gate (2 to 13) is the furthest gate it uses. Lower it when the radar sees past the room, for example through a thin wall.
• LD2412 Minimum Distance Gate (1 to 12) is the closest gate it uses.
• LD2412 Distance Resolution changes the length of a gate: 0.2 m, 0.5 m or 0.75 m. A smaller value gives more precision but a shorter range.

Thresholds per gate are not among the planned entities.

LD2450 Zones

The LD2450 has 3 rectangular zones in the radar. Coordinates are in millimeters, with the sensor at zero.

1. Walk through the area you want and note LD2450 Target 1 X and LD2450 Target 1 Y at the corners.
2. Enter them in LD2450 Zone 1 X1, Y1, X2 and Y2.
3. Set LD2450 Zone Type:
   • Detection: the radar only reports targets inside the zones.
   • Filter: the radar ignores targets inside the zones.
   • Disabled: no zone filtering.
4. Check LD2450 Zone 1 Target Count while you walk in and out of the zone.

LD2450 Multi Target Tracking switches between tracking several people and one person.

Polygon zones in the Room Designer will follow with release firmware for this configuration.

Radar: LD2460

The firmware will run the LD2460 in top installation mode. Leave Tracking Radar Installation Mode on top. Tracking Radar Installation Height and Tracking Radar Installation Angle are for wall mounting and are not needed on the ceiling.

Walk Test

Do this before you draw zones in the Room Designer.

1. Walk in a straight line through the room and watch Tracking Target 1 X and Tracking Target 1 Y. One of them should change clearly.
2. Walk at a right angle to that line. Now the other coordinate should change clearly.
3. Sit still in the area you care about and check that you stay detected.

The LD2460 reports coordinates in steps of 0.1 m, so small jumps are normal.

Detection Range

Tracking Radar Detection Distance, Tracking Radar Detection Start Angle and Tracking Radar Detection End Angle create one detection sector in the radar. On the ceiling the radar accepts 0.1 to 4.0 m and 0 to 360 degrees. The start angle must be lower than the end angle.

Use this to cut off a whole direction at the source. For irregular room shapes, use the polygon and exclusion zones in the Room Designer.

The radar stores these settings itself. After a restart the entities can show unknown for a moment, and changing a value can briefly pause target updates.

Reflections

Mirrors, metal wardrobes, windows and other large reflective surfaces can create a second stable target or shift a position.

1. Temporarily cover the surface to confirm the cause.
2. Remove a whole direction with the detection angles, or draw an exclusion zone in the Room Designer for a local area. The radar has two exclusion slots.

Sensitivity

Sensitivity of the LD2460 is not a Home Assistant entity. It is available through the HLK Radar Tool app, and the module stores the setting.

Radar: LD6002B

Tuning options for the LD6002B follow with the firmware, which is not finished yet.

Light Sensor

Illuminance shows the light level in lux. The sensor measures the light that reaches the ceiling, not the light on your desk. There is no offset entity for light, and whether a separate corrected value follows, as on CeilSense V2, is decided with the firmware.

For automations, simply use the value the entity shows when the room is as bright as you want it. To compare with a lux meter, hold the meter just below the sensor with the LED ring off and compare at several light levels.

CO2

Automatic self-calibration is planned to be off on CeilSense Pro, unlike on CeilSense V2. The reading will not correct itself over time, so you decide when to calibrate with SCD41 Calibrate Fresh Air.

The button sets the reading to 426 ppm, so it only belongs in fresh air. Use it with care, because a press in stale air shifts the readings that follow.

1. Ventilate the room well, with no people in it. Fresh outdoor air is about 400 to 430 ppm.
2. Wait until SCD41 CO2 is stable.
3. Press SCD41 Calibrate Fresh Air on the device page under Configuration.

The SCD41 is planned to use the air pressure from the BMP388 for compensation. You do not need to set anything for this.

Temperature and Humidity

Recessed mounting and heat from electronics influence the temperature reading. Use temperature mainly for trends and wait until the sensor has stabilized after a start before you judge it.

SCD41 Extra Temperature Offset and SCD41 Humidity Offset correct the SCD41 readings without reflashing. They run from -20 to +20 in steps of 0.1 and are kept after a restart. SCD41 Humidity Offset starts at 0. SCD41 Extra Temperature Offset comes on top of the factory correction and its starting value is set by the firmware, so it may not be 0. Note the value that is there before you change it.

1. Make a comparison as described at the top of this page.
2. Calculate the difference: reference minus reading.
3. Add that difference to the value of the offset on the device page under Configuration.

Examples:

• SCD41 Temperature reads 24.5 °C and your reference reads 23.8 °C: the difference is -0.7, so lower SCD41 Extra Temperature Offset by 0.7.
• SCD41 Humidity reads 48% and your reference reads 52%: the difference is 4, so raise SCD41 Humidity Offset by 4.

Both offsets only change the value that is shown. SCD41 Extra Temperature Offset does not recalculate humidity, so check humidity separately. Neither offset has any effect on CO2.

The entities and settings of the SHT45 follow with release firmware.

VOC and NOx

The SGP41 gives indices from 1 to 500, not ppm. There is nothing to calibrate. After a start or a move, allow several hours of normal operation before you judge the readings, and look at trends instead of single values.

Air Pressure

BMP388 Pressure needs no calibration and has no offset entity. BMP388 Temperature is the temperature inside the device, so do not compare it with room temperature.

Optical Smoke Sensing

There is nothing for you to calibrate. The measurement builds its own baseline after every start, is not calibrated against any smoke alarm standard and is not a safety function. See Optical Smoke Sensing.

Good to Know

• Keep notes of the settings and offsets you changed.
• Check the calibration again after you move the sensor.
• Radar settings are stored in the radar module. LD2412 Factory Reset and LD2450 Factory Reset put them back to factory settings.

Related

• Sensor Definitions
• Radar and Sensor Modules
• Troubleshooting