How to use Lux Meter

Steps, videos and tips for the app and its tools.

See the light at a desk, a plant or a photo subject using your phone’s light sensor. Compare positions, watch changes over time and save readings with charts, notes and media.

Watch how it works.

Lux Meter light-level reading

Video coming soon

Getting started

Choose a page

Meter shows the live reading. Tools opens the extra measurement and logging pages; Saved opens kept work; Settings holds the tool and general options.

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Read the steps

Basics

Step by step.

Get started

  1. Choose a page

    Meter shows the live reading. Tools opens the extra measurement and logging pages; Saved opens kept work; Settings holds the tool and general options.

  2. Choose Room, Plants or Photo

    Pick Room, Plants or Photo. Room compares the light with the recommended level for a place, from homes and offices to hospitals, labs and shops. Plants works out plant light (PPFD) and daily light (DLI) for the light source, hours and plant you pick, and Photo gives the aperture and shutter for your ISO.

  3. Start, mark and stop a light log

    Record starts the light log: Stop saves it to Saved, Marker marks a moment in it and Pause pauses it.

  4. Choose audio or video with the log

    The right part of Record picks Log; Audio, the log's sound, saved with the log, which Record starts when none runs; or Video, which films the light with the reading drawn on.

  5. Choose a camera mode and reading overlay

    Video opens the capture camera. Choose Image for a photo or Video for a video. On the picture picks the display saved with the capture: Level bars, Graph, Number, Meter display or Off.

  6. Review captures and choose the camera

    In the camera, the thumbnail opens the latest image or video in the gallery. Use the flash button for lighting and Switch camera to choose the front or back camera.

  7. Choose display, hold and reading options

    Settings has Screen layout, Voice commands, Auto-hold when steady, Speak readings and Darken the screen in dim light, then Readings: Tilt check, Dark offset (cover the sensor and set it, so the dark reads zero), Calibrate, Place on saves and Find the sensor.

  8. Open the light tour

    Settings › Tour & lessons, the first row of the meter's settings, has the Tour (the welcome's Take the tour plays it too): short pages on Room, Plants, Photo, the light log and calibrating, each with Try it.

  9. Choose when tips appear

    The Tips switch turns on or off the tips that show once, at the moment they help; Show all tips again brings them back.

Measure

  1. Save or hold a light reading

    Save saves the reading in Records, on the Saved tab, and with Place on saves also where it was taken, for the map. Pause holds a reading on screen; Settings › Auto-hold when steady takes it by itself once the light is steady.

  2. Review the log’s audio recording

    While audio records, Record reads Stop with the recording's time; a stopped recording waits over the meter with Share and Cancel, and goes with the log when you save it, where its page in Saved plays and shares it. Use the audio slider to jump to a specific time.

  3. Explore plant, recorder and camera tools

    More tools: Plant list and Grow lamp height for plants; Recorder, with Darkness alarm, Bedroom darkness and Daylight today; Light map walk; Saved readings, your readings on a map with a PDF Report you can sign; and with the camera Color temperature, Flicker, Surface brightness, Sky darkness and Cine meter.

  4. Face the sensor toward the light

    Open the Lux meter and face the top edge of the screen toward the light. Keep your fingers off the sensor.

  5. Find light logs, maps and plant tools

    The Tools tab lists every light tool in groups, starting with Logs and maps: Log, Recorder, Light map walk and Saved readings, your readings on a map. Canopy map, under Plants, measures the light over your plants spot by spot, and Log charts the light over time once you start it; Record audio, at the end of its page on Room and Plants, records the log's sound from Start too.

  6. Recognize the sensor’s limit

    When the light is brighter than the sensor can read, the meter shows Sensor maxed out.

  7. Compare the light in different places

    Tools › Compare places shows your rooms and places on the sky scale with the light here among them and where it would rank. Tap Once to add the place you're in with this reading, or Average to measure it for a few seconds (⋮ › Average length), then give it a title, a description and a photo or video. Tap a place to change it or measure it again; ⋮ › Side by side shows two places together.

  8. Explore features and practise with lessons

    The showroom shows every feature with a short film and the way to it, and Lessons teach each part on the live sensor, where nothing you do is kept: no logs, saved readings or settings.

Save

  1. Save tool exports to Documents

    Where a light tool shares a CSV, KML or PDF file, Save puts it in the phone's Documents folder instead; on the walk, ⋮ shares or saves the track as CSV or KML, and the recorder's ⋮ shares or saves its CSV.

Calibrate

  1. Calibrate the light sensor

    Calibrate takes what a lux meter beside the phone reads, or a factor you set on its scale; How to calibrate shows the steps, and Reset goes back to × 1.00.

Guided tour

Try these steps in the app. All tour instructions stay readable here.

  1. Is there enough light to work?

    Lay the phone where you work, screen up: the sensor sits on its top edge. Pick the place and it says whether the light is enough.

  2. Will the basil grow here?

    Hold the phone at leaf height. Pick the light source and its hours: you get the plant light, the light it gathers a day, and a verdict.

  3. Set the camera by the light

    Hold the phone at your subject, top edge to the camera. Set the ISO and the aperture; the shutter speed follows.

  4. Keep a light log

    While the tool is open and the screen is on, Record keeps a reading every 5 seconds until Stop. Mark each change, like the lamp going on; Stop saves it with its chart.

  5. Review a room or lamp change

    Mark a change while the log runs, then stop it. Open the result in Saved to see its readings and chart together and create a PDF Log report.

Tool guides.

Each tool in Lux Meter has its own guide.

Tips.

Use Find the sensor first and keep fingers, a case edge and your own shadow clear of it.

For a workspace, measure where the work is done, with the phone in the same orientation each time.

For plants, measure at leaf height and select the actual light source and its hours before comparing daily-light estimates.

For incident-light photo readings, hold the sensor at the subject rather than at the camera.

If you have a trusted lux meter, place both in the same light and calibrate the phone against it.

Mark a log when a lamp switches on or the position changes so the chart explains what happened.

Still stuck?