We read everything. One person answers, usually within a working day.
A bug, a feature request, a material you would like added, or a result that disagrees with what you expected — all welcome. If you are reporting a result that looks wrong, the checklist below says what to include; without those details it is guesswork on both sides.
2-Sensor mode is free with no limitations. One purchase unlocks the multi-sensor modes — 3-Sensor, 3-Sen+, 4-Sensor, 4-Sen+, 3D and 3D+. It is a one-time purchase, not a subscription.
Everything else is in the free version too: the materials library with temperature compensation, your own custom materials, photo annotation, PDF reports, and measurement backup and restore.
Open the unlock screen and tap Restore purchase (or, in Settings › Upgrade, Restore previous purchase), signed in to the same App Store or Google Play account you bought with. The unlock is tied to that store account, not to the device. If it still does not restore, write to us with the store receipt and we will sort it out.
First, check the first sensor dropdown for each pair. That setting carries the sign of the time difference, and getting it the wrong way round is the single most common cause of a position that looks wrong.
If that is right, there is a real limitation worth knowing about. In 3-Sensor and in 3D the measurement is exactly determined: two positions can fit your numbers equally well, and the app shows one of them without saying so. For a source inside the sensor array this does not happen — that is the case the app is built for. For a source outside the array, it can. If the answer looks mirrored, measure one more pair and use 3-Sen+ or 3D+: those are over-determined, so the second solution disappears, and the RMS residual they report tells you how well your measurements agree with each other.
The most reliable figure is the one you measure on the part in front of you: that is what the calibration step is for — a known distance and the time the wave takes to cross it. The materials library is there when you cannot calibrate, and it compensates for temperature, but a handbook figure for "steel" can be some way from the panel you are standing next to.
Accelerometers and something to capture their signals with enough time resolution to read the difference in arrival times — an oscilloscope or a measurement system. The app does the geometry; the arrival times come from your instrument.
You can add your own material in the app. If you think a shipped figure is wrong, send it with the source you are comparing against and we will check it.
At nvh.evdiag.net, in 30 languages — a full user guide and a one-page quick reference.
Yes, that is what they are for. Print them, put your name on them, hand them to customers. The measurement is your professional judgement, not ours.