Robin: Solenoid Designer

Robin is a complete design app for axisymmetric solenoid magnets. It allows you to go from a first geometry sketch to field maps, inductance, and harmonic analysis, and it runs entirely on your Android phone or tablet. Build a magnet from stacked coil sections, each with its own dimensions, turns, and current. A live geometry preview keeps the cross-section in front of you while you iterate, and every project is saved on your device. No account, no cloud — it runs completely offline. DESIGN • Create magnets from any number of coaxial coil sections • Live cross-section preview with real dimensions and true proportions • Work in mm, cm, m, inches, mils, or feet • Per-project length units, light and dark theme FIELD • Full B(r,z) field maps: Br, Bz, and |B| on a configurable grid • Fast native solver for interactive recalculation • Pan and zoom the field slice; adjustable display and resolution ANALYSIS • Self- and mutual-inductance matrix for all coil sections • Coupling matrix and total stored magnetic energy • Zonal harmonic coefficients for field-quality work PROJECTS • Unlimited projects, stored locally with instant switching • CSV import and export for coil geometries • A built-in sample project to start from Robin is built for physicists, magnet engineers, and students who want real magnetostatics wherever they work. The solver is a native C++ compute core validated against closed-form solutions — the same core that powers the iOS version, verified to match it to within 1e-12 relative. A full field map takes moments, not minutes. Everything stays on your device. Robin collects no data and never connects to the internet.