Calibration Guide for UltimateSensor

Calibrating your UltimateSensor ensures accurate measurements of CO2 levels, environmental parameters, and presence detection. Follow these steps to properly calibrate your sensor.

mmWave Radar Calibration (LD2450)

The UltimateSensor uses the Hi-Link LD2450 mmWave radar for presence detection. This sensor can track up to 3 people simultaneously with position tracking. If you're experiencing issues like constant presence detection or missed detections, follow this calibration guide.

Common Issue: Constant Presence Detection

If your UltimateSensor always shows "occupied" even when the room is empty, this is usually caused by:

• Detection through walls: The 24GHz radar can penetrate drywall and thin walls
• Reflections from objects: Large metal objects, mirrors, or glass can cause false reflections
• Zone configuration: Detection zones may extend beyond your room
• Sensor sensitivity: Default settings may be too sensitive for your environment

Method 1: Zone Configuration via Home Assistant (Recommended)

The LD2450 uses zone-based detection rather than gate-based. You can configure up to 4 detection zones:

1. Open Home Assistant → Settings → Devices & Services → ESPHome
2. Select your UltimateSensor device
3. Configure zone boundaries:

Setting	Description	Range
Zone X Begin X	Left boundary	-4000 to 4000 mm
Zone X End X	Right boundary	-4000 to 4000 mm
Zone X Begin Y	Near boundary (closest to sensor)	0 to 6000 mm
Zone X End Y	Far boundary (furthest from sensor)	0 to 6000 mm

Understanding the coordinate system:

        Sensor (0,0)
           |
    -X <---+---> +X
           |
           v
          +Y (distance from sensor)

Example: Limit detection to a 3m × 4m area directly in front:

• Zone 1 Begin X: -1500 (1.5m left)
• Zone 1 End X: 1500 (1.5m right)
• Zone 1 Begin Y: 0 (start at sensor)
• Zone 1 End Y: 4000 (4m away)

4. Adjust Max Distance:

   • Find "Max Distance" setting
   • Reduce from 600cm to match your actual room size
   • This prevents detection through walls into adjacent rooms

5. Set Occupancy Off Delay:

   • Increase the delay if presence flickers on/off
   • Recommended: 5-15 seconds for most rooms

Method 2: Via HLK Radar Tool App (Bluetooth)

The official Hi-Link app provides a visual interface for tuning the LD2450:

1. Download the app:

   • iOS: Search "HLK Radar Tool" in the App Store
   • Android: Search "HLK Radar Tool" in Google Play Store

2. Enable Bluetooth on the sensor:

   • The LD2450 has Bluetooth enabled by default
   • Make sure your phone is within Bluetooth range (a few meters)

3. Connect to the sensor:

   • Open the HLK Radar Tool app
   • Select "LD2450" as the device type
   • Scan for nearby devices and connect
   • The sensor will appear with its MAC address

4. Available settings in the app:

   • Detection zones: Configure X/Y boundaries visually
   • Max detection distance: Limit the radar range
   • Target tracking: View real-time target positions
   • Firmware update: Update to latest firmware if available

5. Save your configuration after making changes

Tip: The app shows a real-time visualization of detected targets. Walk around your room while watching the app to understand how the sensor sees your space.

Troubleshooting Constant Presence

If you still have constant presence detection after configuration:

Issue	Cause	Solution
Always shows occupied	Detecting through walls	Reduce Max Distance, shrink zone boundaries
Detects pets	Animals in detection zone	Adjust zone height (Y boundaries) to exclude floor level
Flickers on/off	Person at zone edge	Increase zone size or adjust Off Delay
Detects ceiling fan	Moving objects in zone	Adjust zone to exclude fan area
Random triggers	Reflections from metal/glass	Reposition sensor or adjust zones away from reflective surfaces

Testing Your Configuration

After adjusting settings:

1. Leave the room completely and verify "Occupancy" shows OFF
2. Enter the room and check detection speed (should detect within 1-2 seconds)
3. Sit still for a few minutes and verify presence is maintained
4. Walk to room edges and verify zone boundaries work as expected
5. Check adjacent rooms to ensure no false triggers through walls

Advanced: Target Tracking Entities

The LD2450 provides detailed tracking data for up to 3 targets:

Entity	Description
Target X Active	Whether target X is currently detected
Target X Distance	Distance to target in mm
Target X X	Horizontal position (left/right) in mm
Target X Y	Depth position (distance from sensor) in mm
Target X Speed	Movement speed in m/s
Target X Angle	Angle from sensor center in degrees

Use these entities to debug detection issues — if a target shows constant activity when the room is empty, you've found the source of false triggers.

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CO2 Sensor Calibration

The UltimateSensor uses the SCD41.

SCD41 Specifications

• CO2 Measurement Range: 400 to 5,000 ppm
• Temperature Measurement Range: -10 to 60 °C (14 to 140 °F)
• Humidity Measurement Range: 0 to 100 %RH

CO2 Accuracy Specifications:

• 400-1,000 ppm: ±(50 ppm + 2.5% of reading)
• 1,001-2,000 ppm: ±(50 ppm + 3% of reading)
• 2,001-5,000 ppm: ±(40 ppm + 5% of reading)

1. Automatic Baseline Calibration (ABC)

   • The sensor uses an Automatic Baseline Calibration (ABC) algorithm to self-calibrate over time. Ensure the sensor is exposed to fresh air (400 ppm CO2) regularly for the ABC to function correctly.

2. Manual Calibration

   • If you need to calibrate the sensor manually, follow these steps:

     Step-by-Step Manual Calibration via Home Assistant

     1. Prepare the Environment & Ultimate Sensor Mini

        • Place the Ultimate Sensor outdoors on a clear day within range of your WiFi network (note that the sensor is not waterproof). Power on the UltimateSensor and wait at least 5 minutes before continuing to the next step.

     2. Access Home Assistant

        • Open Home Assistant in your web browser or the mobile app.

     3. Navigate to ESPHome Integration

        • Go to Settings.
        • Select Devices & Services.
        • Find and open the ESPHome integration.

     4. Select UltimateSensor Mini

        • Locate the UltimateSensor device from the list of ESPHome devices.
        • Click on the device to open its settings.

     5. Calibrate the CO2 Sensor

        • Press the Calibrate CO2 button in the Controls section. The sensor will start to calibrate. Let the calibration process run for at least 1 minute. Note: The sensor is calibrated to 419 ppm. As of April 2022, the average fresh air CO2 concentration is 419 ppm.

     6. Verify Calibration

        • After calibrating, verify that the CO2 readings are accurate.
        • You may need to repeat the process or adjust the settings if the readings are not correct.

CO2 Levels and Health Implications

The levels of CO2 in the air and potential health effects are:

• 350-450 ppm: Healthy outdoor air level.
• 600 ppm: Healthy indoor air level.
• 800 ppm: Acceptable level for indoor air quality.
• 1,000 ppm: Ventilation recommended.
• 1,200 ppm: Ventilation necessary.
• 2,000 ppm: Negative health effects, such as drowsiness and poor air quality.
• 5,000 ppm: Dangerous with long-term exposure.

Temperature and Humidity Sensor Calibration

1. Temperature Calibration

   • Ensure the sensor is placed in a stable environment with a known temperature.
   • Adjust the temperature offset in the ESPHome YAML to match the known temperature.

2. Humidity Calibration

   • Place the sensor in an environment with a known humidity level.
   • Adjust the humidity offset in the ESPHome YAML to match the known humidity.

Light Intensity Sensor Calibration

1. Calibration Steps
   • Use a lux meter to measure the light intensity in the sensor’s environment.
   • Adjust the light sensor’s readings in the ESPHome YAML to match the lux meter reading.

VOC and Particulate Matter Sensor Calibration

1. VOC Calibration

   • Place the sensor in an environment with known VOC levels.
   • Adjust the sensor's ESPHome YAML to adjust the VOC readings accordingly.

2. Particulate Matter Calibration

   • Use a reliable particulate matter reference device to measure the PM levels.
   • Adjust the sensor’s PM readings in the ESPHome YAML to match the reference device.

Additional Notes

• Calibration Frequency

  • Regular calibration ensures ongoing accuracy. Perform manual calibration every 6-12 months or after relocating the sensor.

• Environmental Factors

  • Avoid placing the sensor in direct sunlight or areas with extreme temperatures and humidity for prolonged periods.

For detailed instructions, refer to the ESPHome or Home Assistant documentation on sensor calibration. If you encounter issues, join our Discord community for support.

By following these calibration steps, you can ensure that your UltimateSensor provides accurate and reliable environmental data for your smart home system.