Support
Trueplane for iPhone
Questions, bug reports and suggestions are welcome by email:
Please include your iPhone model and iOS version. Replies usually within a few working days.
Frequently asked
The reading is not exactly zero on a surface I know is level.
That is your device's factory sensor offset, and it is normal. Run
Settings → Calibrate device. The two-position routine measures the offset
and removes it from every orientation.
What is the difference between Set Zero and Calibrate?
Calibrate corrects the instrument — it removes your phone's own error, once per
device. Set Zero changes what you compare against — it declares the current
surface to be zero, so you can match one surface to another. Both are explained
inside the app under Settings → How it works.
What does a negative reading mean?
Plus means the right or top edge is the high side; minus means it falls away the
other way. The bubble always drifts toward the high side, like a real spirit
level.
How accurate is it?
Sensor noise on a modern iPhone sits around 0.02–0.05°. While the device rests
still and the status reads “Steady”, averaging reduces that by roughly
a factor of ten. Moving in the hand, expect considerably less.
The numbers change too quickly to read.
Settings → Readout refresh. Each update shows the average over its
interval, so a slower setting is both calmer and more accurate. The vial keeps
tracking live regardless.
Can I get my measurements out of the app?
Yes. History → share icon exports everything as CSV, in degrees.