Built Heightly, a web app that measures your height with just your phone camera and a sheet of paper.

Parents still track their kids’ growth with pencil marks on a door frame, and most height apps either need AR (which doesn’t work in iPhone browsers) or just guess. I wanted something anyone can open from a link, on any phone, so I built it on Base44:

📄 A sheet of A4 paper becomes the ruler. The app finds it automatically and snaps to its edges 🧍 Real-time body detection finds the head and feet and guides you into place (paper, distance, straight phone, height) 🎯 Takes 10 readings, locks the result in about 10 seconds, and refuses impossible results instead of guessing 📈 Saves heights for the whole family, calculates growth automatically and flags who’s due to measure again 🔒 Privacy first: photos stay on your phone

Process: I designed every screen first, then built and tested it. My first version showed a random number 😅, so I added pose detection and a paper-based scale, then fixed issues like distance changing the result, until a known-height test read within about 1 cm.

Live App: https://grow-track-spot.base44.app