phone-sensors

Single-file HTML tools probing what a smartphone's sensors can do from inside a browser. No apps, no installs, no servers. This page requests nothing — green badges mean your device can run the tool. source

Combine these

Every tool here is a part. The interesting projects are compositions — proof: echolocation.html is just mic-range's FFT pointed at hearing-range's tone generator.

camera + OCR + IndexedDB → walk a bookstore, catalog every spine shelf-by-shelf (an OpenBookMap). Parts: ocr-spine-select.

accelerometer + geolocation → pothole logger: every jolt above threshold stamped with GPS coordinates. Parts: gait-fingerprint's peak detector.

speaker chirp + mic FFT → sonar. Already exists: echolocation measures distance to walls from echo time-of-flight.

flashlight Morse TX + camera Morse RX → optical chat between two phones, no radio, with the Vigenère layer from morse-transmit. Parts: morse-light, morse-vision.

magnetometer + dead reckoning → walk a room, map wiring and pipes in the walls. Parts: magnetometer-waterfall, inertial-blueprint.

camera pulse + Web Audio synth → your heartbeat as a drone instrument. Parts: heartRate, sensor-etch's violin.

What the browser can't reach

The gaps are the privacy lesson. The phone has all of these; each "no" below is a deliberate decision — WiFi scan results alone would let any page geolocate you within meters, indoors, silently.

Sensor	Web access?
Camera, microphone	Yes, with permission
Accelerometer, gyroscope, compass	Yes — iOS prompts once, Android Chrome asks nothing
Magnetometer (raw)	Chrome only, behind a flag
GPS	Yes, standard geolocation API, with permission
Bluetooth LE	Chrome only — not iOS Safari, not Firefox
WiFi scanning	No, anywhere
Cell tower / signal strength	No, anywhere
Barometer (pressure)	No
Heart rate / SpO2 sensor	No (native apps only — but see the camera-PPG workaround above)
LiDAR depth	No
Fingerprint / Face ID	Authentication only via WebAuthn, never raw biometrics