Sensors and Measurement Data¶

Kamerplanter is designed for four data sources for climate, substrate, and light data: automatic IoT/MQTT sensors, Home Assistant, weather services for outdoor and greenhouse locations, and manual entry. Home Assistant (automatic polling), weather services (for outdoor/greenhouse locations with GPS coordinates), and manual entry at the tank are currently usable in production — the direct IoT/MQTT connection is specified but not yet implemented (details below).

Prerequisites¶

• At least one location set up (site or location)
• For automatic data: sensors linked in Home Assistant and Kamerplanter connected to Home Assistant — see Home Assistant Integration

The Data Sources at a Glance¶

The specification defines a four-tier fallback chain. Currently, two automatic paths (Home Assistant and weather services for outdoor/greenhouse locations) and manual entry at the tank are implemented — only the direct IoT/MQTT connection is still missing:

1. Automatic (IoT/MQTT) — planned
2. Home Assistant REST API — REAL, implemented
3. Weather service (outdoor/greenhouse only) — REAL, implemented
4. Manual entry — REAL, currently tank only

1. Automatic (IoT/MQTT) — planned The sensor data model already has an mqtt_topic field reserved for a future direct MQTT connection. This ingestion path is not yet implemented — the field currently has no effect and does not need to be filled in.

2. Home Assistant (automatic) A background job polls the current value of every active sensor with a configured HA entity ID every 5 minutes and writes it to the time-series database (source ha_auto). This is one of two automatic paths currently implemented.

3. Weather service (outdoor/greenhouse only) For outdoor and greenhouse locations with stored GPS coordinates, you can configure and prioritize one or more weather services (Open-Meteo, German Weather Service, OpenWeatherMap) or your own Home Assistant weather source as a data source — if your preferred source becomes unavailable, the next one automatically takes over. See Weather Sources per Location for details.

4. Manual Entry — currently tank only

Linking Sensors to a Location¶

Step 1: Open Site or Location¶

Navigate to Locations and open the site or location the sensor belongs to.

Step 2: Add Sensor¶

In the Sensors section, click Add Sensor.

Step 3: Configure the Sensor¶

Fill in the form:

HA Entity Autocomplete¶

If Home Assistant is configured, the dialog automatically loads the available Home Assistant entities when opened. Selecting an entity from the list makes Kamerplanter automatically fill in:

• the suggested sensor name,
• the matching unit of measurement,
• a suggested metric type (if Home Assistant provides a device_class from which the metric type can be derived),
• the entity ID itself.

If no Home Assistant entities are found (e.g. because no HA integration is set up or Home Assistant is currently unreachable), the dialog instead shows a free-text HA Entity ID field where you enter the entity name manually.

Metric Types in the Form¶

The metric type is chosen from a fixed list:

The first four metric types (temperature, humidity, VPD, CO2) and PPFD are typical for climate sensors on a site/location. The rest (pH, EC, water temperature, TDS, dissolved oxygen, ORP, fill level) are mainly relevant for tanks — see Tank Management. The form does not technically enforce this mapping; for example, you can also create an external EC sensor on a location.

Understanding Monitored Parameters¶

Climate Parameters¶

Temperature (°C) Air temperature in the growing area. Optimal ranges depend on phase — typically 22–26 °C in the vegetative phase, 18–24 °C in flowering.

Relative Humidity (rH, %) Too high humidity promotes mould (Botrytis, powdery mildew). Too low humidity increases water stress.

VPD (kPa) — Vapor Pressure Deficit VPD is the most important climate parameter for optimal plant growth. It combines temperature and humidity into a single value describing how strongly the air draws moisture from leaves:

• VPD too low (< 0.4 kPa): Plant transpires too little, nutrient uptake reduced, mould risk
• VPD optimal (0.8–1.2 kPa): Best growth and nutrient uptake
• VPD too high (> 1.6 kPa): Plant closes stomata, nutrient deficiency despite adequate fertilization

Kamerplanter calculates VPD from temperature and humidity (Tetens formula) and compares it against the target for the active growth phase.

CO2 concentration (ppm) Normal indoor air: approximately 400–500 ppm. Plants benefit from 800–1500 ppm (with sufficient light). Above 1500 ppm brings little additional benefit and may cause discomfort for people.

Water and Nutrient Solution Parameters (Tank)¶

In practice, these values are recorded at the tank — automatically via Home Assistant or manually (see Tank Management):

EC (mS/cm) Electrical conductivity of the nutrient solution shows salt concentration. Significantly higher runoff EC than input EC signals salt accumulation in the substrate and is a sign that a flush is needed.

pH Value pH determines nutrient availability. Outside the optimal range (hydroponics: 5.5–6.5; soil: 6.0–7.0) plants cannot absorb nutrients even when enough is present.

Water temperature, TDS, dissolved oxygen, ORP Additional water quality metrics, especially relevant for hydroponic/aquaponic systems. Dissolved oxygen is important for root health in nutrient-solution systems without substrate (e.g. DWC — Deep Water Culture, see Tank Management).

Light Parameters¶

PPFD (µmol/m²/s) — Photosynthetic Photon Flux Density Indicates how much photosynthetically useful light reaches the plant per second. Rough guidelines:

• Low light plants: 100–300 µmol/m²/s
• Medium light plants: 300–600 µmol/m²/s
• High light plants: 600–1200+ µmol/m²/s

DLI (mol/m²/d) — Daily Light Integral DLI is not a stand-alone sensor reading; it is calculated from PPFD × lighting duration — among other things as part of photoperiod transition schedules (see Environment Control & Actuators).

Outdoor Sensors: Setting Up a Weather Service¶

If you have no outdoor sensor of your own, you can instead retrieve climate data from a weather service or your Home Assistant installation — configured per site in the Weather Source section of the site detail page.

In short:

1. The site needs GPS coordinates (currently only editable via the API — see Locations & Substrates).
2. You select a public weather service (Open-Meteo — recommended, no API key required; German Weather Service; OpenWeatherMap — requires your own API key) or your Home Assistant weather source.
3. Optionally, you prioritize several sources as a fallback chain and check each source before saving via Test Source.

For the full step-by-step guide, see Weather Sources per Location.

Sensor Failures, Fallback, and Interpolation¶

The planned behavior is as follows: if a sensor delivers no data for more than 6 hours, Kamerplanter will detect the failure, show a warning, switch to the next available source, and create a "Check sensor" task. Short outages (under 2 hours) are planned to be bridged by interpolating the last known values.

Data Retention¶

Automatically collected measurements are downsampled in stages and eventually deleted (raw data 90 days, then hourly and daily averages — see Data Retention & Anonymization).

Frequently Asked Questions¶

See Also¶

• My Plant Doesn't Look Well — Symptom Diagnosis
• Weather Sources per Location
• Dashboard
• Tasks
• Tank Management
• Home Assistant Integration
• Data Retention & Anonymization
• Guides: VPD Optimisation