Indoor illuminance chart card with background

Who it’s for

Facility managers, building automation engineers, and workplace managers ask “how has illuminance trended in this space recently?” The chart with background combines a compact trend line with a full-card color signal so the current status is visible at a distance.

What it does

A sensor reporting illuminance = 350 lx renders a time-series trend chart on a card whose background color reflects the current band: dark gray for Dim (0–100 lx), orange for Low (100–300 lx), dark orange for Moderate (300–500 lx), and red for Bright (above 500 lx).

• Full-card background color makes illuminance status readable across a room without reading the number
• Trend chart of illuminance over the selected dashboard time window
• Shows one sensor’s data per widget; add multiple widgets to compare trends and current status across zones

How to set up

Data keys

Key	Role	Type	Description
illuminance	Chart series	Timeseries	Illuminance in lx; change the key name to match your device’s telemetry key
Latest	Latest value	Timeseries	The headline figure above the chart. Its own color ranges are where the band colors are edited
Delta percent	Percentage change	Timeseries	Change against the previous period, as a percentage
Delta absolute	Absolute change	Timeseries	Change against the previous period, in the key’s own unit

The widget ships with a simulated function datasource key labeled Illuminance, so it draws random values until you point the datasource at a device and rename the key.

To point it at your own device: open the dashboard in edit mode, open the widget’s Datasources, pick the entity or entity alias, and replace the function key with the key your device reports.

Value ranges

Range (lx)	Level	Color
0–100	Dim	Dark Gray
100–300	Low	Orange
300–500	Moderate	Dark Orange
500+	Bright	Red

How to customize

• To change the time window — adjust the dashboard time filter to show the last hour, day, or week of illuminance readings.
• To change the band thresholds — open the widget settings and adjust the boundaries to match your space’s lighting standard.
• To change the background colors — edit the color of each range on the Latest data key.

Tips

• On a wall display, the colored background signals the current illuminance band from across the room while the embedded chart shows whether the level is stable or fluctuating due to cloud cover or daylight harvesting corrections.
• Use consistent band colors across all environment widgets so facilities staff can interpret a colored background anywhere on the dashboard without reading the label.
• Rapid illuminance fluctuations visible on the chart — not caused by cloud cover — often indicate a failing lamp ballast or a daylight sensor with a dirty lens causing erratic dimming commands.