phyphox

5 June 20263 min read

Physics experiment app by RWTH Aachen University. Turns the phone into a lab instrument using its built-in sensors. Available on Android (F-Droid, Play Store) and iOS (App Store). Open source under GPLv3.

Sensors Used

Sensor	Data
Accelerometer	Linear acceleration (with/without g), vibration
Gyroscope	Rotation rate (rad/s)
Magnetometer	Magnetic field strength, calibrated/uncalibrated
Microphone	Audio waveform, frequency, amplitude
Speaker	Tone generation, sonar output
Barometer	Absolute pressure (hPa)
GPS	Position, speed, altitude
Ambient light	Illuminance (lux)
Proximity	Near/far state
Camera	Photometric data, depth (LiDAR/ToF where available)
Bluetooth	External sensors via BLE

Built-in Experiments

Mechanics

Experiment	Sensor	Measures
Acceleration (without g)	Accelerometer	Raw linear acceleration
Acceleration with g	Accelerometer	Raw acceleration incl. gravity
Acceleration Spectrum	Accelerometer	FFT of acceleration, dominant frequency
Centrifugal acceleration	Gyroscope + Accelerometer	Relationship between angular and centrifugal acceleration
Inclination	Accelerometer	Angle of inclined plane
Pendulum	Gyroscope	Pendulum frequency → gravitational acceleration
Spring	Accelerometer	Frequency of spring pendulum
Roll	Gyroscope	Rotational speed inside rolling tube
Free fall (magnetic)	Magnetometer	Drop along magnet array → linear acceleration
Motion stopwatch	Accelerometer	Stopwatch triggered by shocks
(In)elastic collision	Accelerometer	Energy loss of bouncing ball

Acoustics

Experiment	Sensor	Measures
Audio Scope	Microphone	10ms oscilloscope view with edge trigger
Audio Spectrum	Microphone	FFT, dominant frequency
Audio Autocorrelation	Microphone	Autocorrelation, signal frequency
Audio Amplitude	Microphone	Signal amplitude (calibratable)
Frequency history	Microphone	Frequency over time
Acoustic Stopwatch	Microphone	Time between sound events
Free fall (acoustic)	Microphone	Fall duration via sound
Doppler effect	Microphone	Doppler shift from a base frequency
Speed of Sound	Microphone (2 phones)	Sound velocity with measuring tape
Sonar	Microphone + Speaker	Distance or speed of sound
Tone Generator	Speaker	Sine tone at configurable frequency

Magnetism

Experiment	Sensor	Measures
Magnetic field	Magnetometer	Raw field data (calibrated/uncalibrated)
Magnetic Spectrum	Magnetometer	FFT of magnetic field
Magnetic ruler	Magnetometer	Speed and distance via magnet markers
Linear acceleration on air track	Magnetometer	Acceleration along magnetic track

Other

Experiment	Sensor	Measures
Elevator	Barometer	Speed and height travelled in elevator
Pressure	Barometer	Raw pressure data
Pressure in a bag	Barometer	Pressure under applied weight
Light	Light sensor	Raw ambient light
Optical stopwatch	Light sensor	Time intervals via brightness threshold
Proximity stopwatch	Proximity	Time intervals via near/far transitions
Gyroscope	Gyroscope	Raw rotation rate
Location (GPS)	GPS	Raw position data

Remote Access

Enable in-app via the menu. Phyphox starts a web server on port 8080 — open http://<phone-ip>:8080 from any browser on the same network to control the experiment and view live graphs.

REST API

All endpoints return JSON. The phone IP and port 8080 are the base URL.

GET /get?<buffer>[=threshold] — read sensor data

/get?time&acc_x&acc_y&acc_z # latest value from each buffer

/get?acc_x=full # entire buffer

/get?time=3 # values where time > 3

/get?acc_x=42|time # values where time buffer > 42

Response:

json

{

"buffer": {

"acc_x": { "size": 1000, "updateMode": "partial", "buffer": [0.12, ...] }

"status": {

"measuring": true,

"timedRun": false,

"session": "abc123"

}

GET /control?cmd=<command> — control experiment

Command	Effect
`?cmd=start`	Start measurement
`?cmd=stop`	Pause measurement
`?cmd=clear`	Clear buffers and stop
`?cmd=set&buffer=abc&value=42`	Write value into a buffer

GET /config — experiment structure (v1.1.6+)

Returns buffer names/sizes, input configuration, and recommended export groups.

GET /meta — device metadata (v1.1.8+)

Returns device and app version information.

GET /time — clock sync (v1.1.8+)

Maps experiment time to Unix time. Response is an array of {experimentTime, systemTime, event} objects (events: start, pause).

GET /export?format=<n> — bulk export

Format	n
Excel	`0`
CSV	`2`

Data Export

From the app: menu → Export. Formats: CSV, TSV, Excel. Can also be triggered over the network via /export.

Custom Experiments

Web Editor

Visual (Blockly-based) editor at phyphox.org/editor. Build experiments by wiring together input, analysis, and view blocks. Export as .phyphox XML file, then load onto device via QR code, URL, or file share.

File Format

Experiments are XML files with a .phyphox extension:

xml

<title>My Experiment</title>

<category>Mechanics</category>

<data-containers>

</data-containers>

<input>

</sensor>

</input>

</analysis>

<views>

</graph>

</view>

</views>

</set>

</export>

</phyphox>

View elements: <graph>, <value>, <edit>, <button>, <slider>, <toggle>, <dropdown>

Input types: accelerometer, gyroscope, magnetometer, pressure, light, proximity, gps, microphone, camera, bluetooth

External Hardware

BLE sensors can be integrated via the Bluetooth input module. Arduino and MicroPython libraries are available for building custom sensor peripherals.

Experiment collection (all built-in .phyphox files): github.com/phyphox/phyphox-experiments