Volume 01 · A precision toolkit
Six instruments.
One trunk.
A spirit level, compass, sound meter, flashlight, on-screen ruler, and protractor — beautifully crafted, all on-device, no logins.
Free
Offline
iOS & Android
— A note from the workshop
Most "all-in-one tools" apps feel like a junk drawer. ToolTrunk is the opposite — each instrument is hand-tuned to feel like a real device, calibrated against the sensor it leans on, and given enough screen to do its job properly.
— Built solo by PlayPal Apps
— The toolkit / six instruments
Six tools, each hand-tuned.
No filler. No upsell screens. No fake features. Just six instruments built to feel like the real thing.
01 — Spirit Level
Spirit Level
Surface (2D bubble) and bar (1D) modes, calibratable to any reference plane. Gentle haptic when you hit true level.
02 — Compass
Compass
True heading with cardinal letters, accuracy readout, and a bearing-lock so you can keep a target while you move.
03 — Sound Meter
Sound Meter
Live decibels on a half-circle gauge with peak / average stats and a smooth chart history of recent samples.
04 — Flashlight
Flashlight
Steady torch, SOS pattern, strobe, plus a coloured screen-light for when the camera flash isn't enough.
05 — Ruler
Ruler
On-screen ruler with credit-card calibration. Drag the line; read millimetres, centimetres, or inches with sub-mm precision.
06 — Protractor
Protractor
Touch-based angle measurement with degree ticks along the arc and snap-to-common-angles at 30 / 45 / 60 / 90.
— Datasheet
A small spec sheet,
in case you care.
Built on the sensors your phone already has. The numbers below describe how each instrument is wired.
Spirit level source 3-axis accelerometer
Compass source Magnetometer
Level filter Low-pass · α = 0.18
Compass tilt comp. Hardware (CoreLocation / SensorManager)
Sound meter source Microphone · meanDecibel
Sound display Half-circle gauge · 90-point trail
Ruler default density 6.30 px/mm (calibratable)
Protractor snap 0, 15, 30, 45, 60, 75, 90 …
Network calls Only Google AdMob, on demand
Local storage Theme, units, calibration
Min Android API 24 (Nougat)
Min iOS iOS 15
Open the trunk.
Free on iOS & Android — no sign-up, no tracking of your measurements.