Datum - Engineering Notebook

Datum is an engineering project notebook for iPad. It keeps everything about a build in one place, so when you come back to a project six months later the reasoning is still sitting next to the drawings. NINE SECTIONS, ONE PROJECT IDEAS Capture thoughts as tagged cards, or use the built-in SCAMPER prompts and design constraints to get past a blank page. The prompt stays attached to your answer. SKETCH A very large sheet of drafting paper with thirteen brushes, adjustable pen sizes, and square, isometric or dot grids. Line-lock modes turn a freehand stroke into a clean straight line, snapped to 15 degrees or to the grid. Rough out a circle or hexagon and it snaps to a precise one. Measure anything in real millimetres once you have calibrated the drawing scale. CIRCUIT Schematic capture with proper symbols. Place components, wire them pin to pin, and build your own parts in a reusable library — give an ESP32 a name, notes and labelled pins on any of the four sides, and mark which pins are mandatory. A rule checker flags floating pins, missing ground or supply, direct shorts and duplicate references. Export a netlist, or push every component straight into your parts list. CAD Import and view STL models. Orbit, zoom, and switch to wireframe to check geometry. BUILD A parts list with suppliers and prices. A budget broken down by category. A cutting list for pieces to cut, mill, drill or print. An ordered build checklist. A work timer that logs hours against phases, so a finished project can tell you what it really cost in time as well as money. TESTING Decide what a pass looks like before you run it, record what actually happened, and keep a lessons-learned log of what broke and why — searchable across every project you have ever built. CALC Around forty engineering formulas, from Ohm's law to cantilever deflection to stepper steps per millimetre. Tap any field to solve for that value instead. Plus a grapher with drag-to-trace, numeric differentiation and integration, and solvers for simultaneous equations and quadratics. PHOTOS Build photos from the camera or your library, marked up with the Apple Pencil. NOTES Free text for decisions, part numbers and datasheet links. Also included: version snapshots you can roll back to, PDF export of a whole project, and templates so the next build starts from the last one. PRIVACY Datum has no account, no analytics and no server. Everything stays on your iPad, and the app makes no network requests at all. Designed for Apple Pencil, with a finger-drawing option if you have not got one to hand.