Explorer Toolkit

Explorer Toolkit turns your phone's sensors into a pocket-sized set of field tools.

Ten instruments, one app, no internet required.

■ Metal Detector

Measure magnetic fields with your phone's magnetometer. The beep gets faster and higher as the field grows stronger, just like a real detector — you can find metal without watching the screen. Set your own alert threshold and get vibration, sound and a flashing screen border when it is crossed. Track the peak value, freeze a reading, and switch between μT and mG.

■ Compass

A tilt-compensated compass that stays accurate even when the phone is not flat.

It shows the live sensor accuracy, and when the reading drifts it demonstrates the figure-8 motion needed to recalibrate.

■ Level

A bubble level for shelves, frames and furniture. Set a custom zero point when the surface you are working from is not flat.

■ GPS

Latitude, longitude, altitude, accuracy and speed, plus your current address.

Copy coordinates or open them in your map app with one tap.

■ Magnetic Map

Record magnetic field strength as you walk. Your path is drawn on the map, coloured by field strength, so you can see where readings spike.

■ Ruler

Measure small objects against the edge of your screen in centimetres or inches.

Calibrate once with a bank card for accurate results on any device.

■ Light Meter

Read ambient light in lux with a live trend graph and a plain-language level.

■ Live Sensors

Watch accelerometer, linear acceleration, gyroscope, magnetometer and barometer data on a real-time graph. Each sensor comes with a one-line explanation of what the numbers mean. Pause and share a screenshot.

■ Device Info

See every sensor your phone actually has, along with chipset, memory, battery and screen details.

■ Measurement History

Save readings with a note and location, then export everything as CSV.

Built for the field

· Dark by default, with a night mode that uses red text to protect your night vision

· Battery saver mode slows sensor updates when you need the app running for a while

· Sensors stop the moment you leave a screen

· Tools that need a sensor your phone does not have will tell you so, instead of failing silently

Location is used only on the GPS and Magnetic Map screens, and only while they are open. Your measurements stay on your device.