How to measure
with it.

Common questions

Does the app send measured data anywhere on its own?

Not until you set it up. The data sits in the phone and leaves only when you share it, download it, or configure a destination under the gear icon (S3, WebDAV or SFTP). The only traffic that flows by itself is the test data of internet mapping and throughput — and even that you have to switch on.

Why does the thermometer read over 45 °C?

Because it measures the phone, not the room. A Pixel has no ambient temperature sensor; the reading comes from a sensor inside the device, warmed by the processor and the radios. During a measurement it commonly reads twenty degrees above the surrounding air. It is a fact about the device — treat it as one.

Why is there no direction drawn for Wi-Fi or Bluetooth?

Because Android does not report one. Azimuth and elevation come from GNSS only, which is why the globe holds satellites and nothing else. Wi-Fi gives strength, RTT gives range, Bluetooth AoA is not in the public API, and cells report only their identity. Samples without direction therefore light the entire ring — a sector would claim a bearing nobody knows.

The light trace is broken up. Is that a fault?

No. The light sensor reports only changes, so on a phone lying still it sends a handful of samples per second. A second without a sample breaks the trace; a line across the gap would pretend to be a measurement that never happened.

Can I lock the phone or switch apps while measuring?

Yes. The measurement runs in a foreground service and continues with the screen locked; the notification shows that it is running. What stops it is switching the phone off or the system killing the app when memory runs low — such a record is kept, marked as interrupted, and can still be downloaded.

How much data does a measurement produce?

With the sensors on, tens of thousands of rows per minute — a half-hour walk produces hundreds of megabytes of raw text. Based on the estimated size, the app offers a GZIP-compressed export by itself, which cuts it to roughly a tenth.

Is the SIM card number recorded?

No. The export carries the operator, MCC/MNC, the slot, roaming and which card carries the data. Neither ICCID nor EID is recorded — they are permanent subscription numbers that outlive even a change of phone.

Is audio recorded?

No. Only an indicative loudness in dBFS is computed from the microphone and the audio is discarded. A number goes into the file, not a recording.

Your first measurement

The app asks for permissions only when it needs them. The shortest path to a first record:

1. Grant the permissions. The Permissions card at the top shows what is granted and what is missing. Location is required even for a Wi-Fi scan — without it Android withholds the list of networks.
2. Check the technologies. The Measured technologies card offers presets and the individual sources. Next to each source name, in smaller type, sits its configured value — 50 ms or 15/45 s, for instance.
3. Press Start. While running, the controls settle under the header and stay within reach even when you scroll further down.
4. Walk. The panel shows the duration, the distance walked and the record count; the digits grow with the rate at which data arrives.
5. Stop and export. Stop ends the session, and the panel below offers a download or a share.

Distance is counted only from fixes that passed the accuracy filter. Indoors it usually stays at zero — that is what points on a floor plan are for.

Choosing technologies

A source is switched on and off by tapping its name. A source with a gear icon opens its settings on a tap, where the interval can be changed — and doing so switches it on as well.

The presets above the list switch the whole set at once. If you have your own intervals set, the app asks before switching whether to keep them as Custom; otherwise the preset would overwrite them.

A tick means “selected”, green means “has measured something”. A source can be selected and still measure nothing — typically when the technology is missing from the phone or switched off.

The sky and the ring

The Sensing card is a view of what the instrument sees right now. Collapsed it shows a compass with a needle to north; expanded, the whole sky.

Inside the globe the satellites sit at their real azimuth and elevation. Colour separates the constellation, size and brightness carry C/N0, a filled dot counts towards the fix. The globe turns and tilts with the phone: face up it looks into the zenith, held upright it looks at the horizon.

Around the globe run bands for the quantities that have no direction — noise, temperature, pressure and light. The angle along a band is time, not bearing: one minute cut into seconds, so the head of the trace sweeps like a second hand with a gap behind it where values have aged out of the minute.

The ring that ripples is a sample without direction — Wi-Fi, Bluetooth, cells. The ripples rotate, so not even the tallest of them points anywhere.

Below the globe is a legend you operate: the arrows step through the items, the middle button switches off the one you are on. A quantity loses its band, a constellation loses its dots. The filter changes the picture, not the measurement — a switched-off item keeps being measured and stays in the list with its value.

Points on a floor plan

Indoors GNSS gives no position, so there is nothing to attach the measured values to. That is what point measurement is for: stop, type a label (a room number from the floor plan, say), tap Mark point and wait a moment for samples to gather. Then walk on.

The label is optional. Without it the point stays a sequence number, which is enough for a walk along a numbered plan.

Internet mapping and throughput

Two features with a card of their own, because they behave unlike every other source: they send data over the network themselves.

Continuous internet mapping

This is not a speed test. Continuously, for the whole walk, it measures real transfer quality — download, upload, RTT, jitter — and every thirty seconds it runs a longer capacity burst. It shows how walls, corners and doors change what a user actually gets.

The card states the upper estimate of data used per half hour up front. It measures over Wi-Fi, cellular, or both at once.

Wi-Fi network throughput

Not a scan either: the phone joins the networks you list one by one, measures how much data flows through each, and disconnects again. Networks are added by SSID; the suggestions under the field come from the last scan, strongest first.

The first connection to each network brings up Android's own dialog. Clear those at the start of the walk — the phone remembers the consent. A network that fails to connect within the limit is recorded as unavailable and the walk continues.

Export and upload

The panel at the bottom offers Download (saves the file through the system dialog) or Share (hands it to another app). Based on the estimated size it switches to GZIP packing on its own.

Under the gear icon in the header are the destinations a measurement can leave for on its own:

Sending a measurement by e-mail is not among the destinations: that is the system app chooser opened by the Share button in the export panel — and mail is in it, alongside Drive or messaging.

Saving a destination switches it on straight away. The Upload after the measurement stops switch then sends every finished record by itself; with the app closed, it speaks up the next time you open it. A manual upload is always available through Upload the last measurement.

Passwords and keys are held in the phone encrypted with a key from the Android Keystore. An address without https:// is rejected for S3 and WebDAV alike — Basic authentication only encodes the password, it does not hide it.

Troubleshooting

A source is selected but measures nothing

Look at the Collection status card — it states what is happening with each technology. The usual reasons: a missing permission, the technology switched off in the phone (Bluetooth, Wi-Fi), or the device not having it at all.

The Wi-Fi scan keeps returning the same thing

Android throttles scans. The app recognises this and records the state THROTTLED or UNCHANGED instead of passing the same result off as a new measurement. Throttling can be switched off in the developer options (Wi‑Fi scan throttling).

The distance stays at zero

Only fixes that passed the accuracy filter are counted. Indoors or under trees the accuracy is worse, and the line under the panel says so — location ±28 m · too coarse, distance is not counted.

The cellular branch reports no network

There is no SIM in the phone, or the card does not carry data. The SIM and eSIM card shows what is in the device and which card carries the data.

The upload to a server failed

The message states the reason. With S3 the culprit is usually the region or the keys, with WebDAV a folder that does not exist — it is not created for you. With SFTP the first upload always ends with the server key fingerprint: compare it against the server and store it in the destination settings.

Where the limits are

The app writes down only what the system gives it and infers nothing. Which sets what you cannot expect from it:

• The direction a signal arrived from for anything other than GNSS.
• A position indoors. That is what marked points are for.
• The room temperature. The sensor measures the device.
• An active cell scan. It requires carrier privileges; an ordinary phone refuses and records the reason.
• The SIM card number. The system does not hand it to an ordinary app — and it would not go into the export even if it did.