Datum — Support

Getting Started

Datum is an engineering project notebook for iPad. Tap + on the project list to create a project, then work through the nine sections down the left-hand sidebar — ideas, sketch, circuit, CAD, build, testing, calc, photos and notes. No account, no sign-up: everything is stored on your own iPad.

A full walkthrough of every section and what each button does is built into the app. It appears the first time you open a project, and you can bring it back any time from the ··· menu at the top of the sidebar, or the ? button on the project list.

Frequently Asked Questions

Do I need an Apple Pencil?
It is much better with one — you get pressure, tilt and palm rejection. But you don't need one. Tap the hand icon in the Sketch toolbar to turn on finger drawing. With it on, pan and zoom using two fingers instead of one.

How do I draw a straight line?
Use the line-lock button in the Sketch toolbar. Set it to Straight and any stroke you draw becomes a clean line between where you started and finished. Angle 15° snaps to the nearest 15 degrees so horizontals and verticals are exact, and Grid snap puts both ends on the nearest grid intersection.

How do measurements work?
Tap the ruler icon and drag across whatever you want to measure. To get real millimetres, first set the drawing scale: tap the scale button next to the ruler, or tap "Calibrate scale" in measure mode and draw along something whose length you already know.

Can I add my own circuit components?
Yes. In the Circuit section, tap Component library at the bottom of the palette, then +. Give the part a name, notes, and pins on any of the four sides — use Add Pins to create several at once. Tick Required on any pin that must be connected, and the circuit checker will raise an error if you leave it floating. Saved parts are reusable across every project.

My STL file won't load.
Datum reads both binary and ASCII .stl files. If a model fails, check the file opens in another viewer — partially downloaded or truncated files are the usual cause. Very large models take a few seconds to parse.

Where is my data stored? Does it sync?
Everything is stored locally on your iPad. There is currently no cloud sync between devices, and the app makes no network requests at all. Your projects are included in your device's normal encrypted backups. See the Privacy Policy for full details.

How do I get my project out of the app?
Open the ··· menu in the sidebar and choose Export PDF. You pick which sections to include and get a single document covering the whole project. You can also share a sketch as an image, share an annotated photo, or export a circuit netlist as a text file from the circuit check sheet.

Can I undo a change?
The Sketch and photo markup canvases have undo and redo buttons. For the wider project, use Snapshots in the ··· menu — take one before a big change and you can roll the sketch, circuit, CAD model and notes back to that point.

The app opened on a screen saying it can't open its database.
That means the stored data doesn't match the current version's data model, usually after an update. Tap Try again first. If it keeps happening, please email me before using Reset local data — that permanently deletes every project on the device, and I would rather help you recover it.

Still need help?

Email chrislegge151@outlook.com and I'll get back to you. It helps if you mention your iPad model, your iPadOS version, and which section of the app you were in.