σT vs TahtX

σT is a precision tool for physics students and researchers who need to propagate measurement uncertainties through calculations. Enter your experimental data, and σT handles the error math automatically. **FIVE ERROR MODES** Configure uncertainties in your data to match your orignal measurement method: • Constant — for physical constants and exact values • Absolute — fixed ±error (ruler measurements, digital readouts) • Relative — percentage-based uncertainty • Combined — both absolute and relative components (many typical multimeters) • Per-Value — individual error for each measurement **AUTOMATIC PROPAGATION** Create derived values and watch uncertainties flow through the calculation chain. σT uses Gaussian error-propagation and pre-calculated derivative-based methods to compute propagated errors correctly when combining independently measured variables. Available operations: • Basic: add, subtract, multiply, divide, reciprocal • Functions: exp, ln, sin, cos, normalize • Statistical & Sample Statistics: mean with standard error, average step width • Advanced: weighted sums, weighted products, polynomials • Physics: Lorentz factor (relativistic gamma), Logit sigmoid (Fermi-Dirac statistics) **INTERACTIVE CHARTS** Visualize your data with proper error bars. Pinch to zoom, drag to pan, double-tap to auto-fit. Add mathematical function overlays to compare your measurements against theoretical predictions, identify eligible parameter ranges matching your measurements. **EXPORT YOUR WORK** • CSV and TSV export for spreadsheets and analysis tools • High-resolution PNG charts for lab reports • Complete project files for sharing with classmates or colleagues • Copy data to clipboard with a swipe and continue in Sheets or Excel with errors in place **DESIGNED FOR LAB WORK** σT adapts to your device: • iPhone: Full-featured portable lab companion • iPad: Side-by-side layout for efficient data entry • Mac: Native desktop experience via Catalyst **YOUR DATA, YOUR DEVICE** All measurements are stored locally. No account required, no cloud sync, no tracking. σT works completely offline.

TahtX brings the classroom whiteboard directly to a student's tablet — designed from the ground up for children and pupils with low vision. Connect any IP camera mounted in the classroom and the live video appears on the student's iPad in landscape, ready to be cropped, zoomed, sharpened and color-shifted into whatever combination makes the writing on the board easy to read from the seat the student is in. KEY FEATURES • Live IP camera viewing — works with most ONVIF-compatible cameras (auto-discovery), or paste any RTSP URL manually. • Pinch-to-zoom up to 10×, two-finger pan, double-tap to toggle 1× ↔ 3× — keep handwriting in focus regardless of where the student is sitting. • Perspective crop — drag four corners onto the whiteboard so the student only sees the board, not the surrounding wall. • Whiteboard mode — a GPU shader binarizes the image into crisp black-and-white at an adjustable threshold, turning faint marker writing into sharp readable text. • 12 high-contrast color themes — yellow on black, black on yellow, green on black, warm light, warm dark, inverted gray and more, each tuned for a different vision profile. • Manual filters — contrast, brightness, sharpness, color tone and full color inversion, persisted across sessions. • 4 UI scale levels — Small / Medium / Large / Extra Large; every label, icon and control resizes so even the menus stay readable. • Low-latency playback — built on the libmpv-based media_kit engine with TCP transport and zero-buffer tuning, so what's on the board is what's on the tablet. • Settings persisted locally — set up once and the app reconnects automatically on launch. • Bilingual — Turkish auto-detected from system language, English everywhere else. WHO IT'S FOR Students with low vision who would otherwise need to sit in the front row, ask classmates to read the board, or strain their eyes from a distance. Teachers and accessibility coordinators looking for a low-cost, repeatable setup using off-the-shelf IP cameras. HARDWARE You need an ONVIF-compatible IP camera (or any camera with an RTSP URL) on the same Wi-Fi network as the iPad. Setup is a one-time process via the in-app Camera Settings screen. PRIVACY TahtX does not collect, transmit or sell any data. The app talks only to the camera you configure on your local network. No accounts. No analytics. No ads. Open source.