In labs handling sample tubes, racks hold dozens of positions, each tied to a sequence number by the filling order. Before scanning tubes into a permanent inventory system, techs need a quick way to pinpoint the right slot, especially under time pressure with hundreds of tubes per rack.

I built FT4ED Locator as a lightweight web app to solve this. Enter a sequence number, and it highlights the exact grid position. Or tap any slot, and it shows the sequence number.

This is useful especially in situations where the tubes may have been placed incorrectly during scanning. The application can help re-orient the tech by allowing them to quickly pinpoint the exact physical location where a tube should be placed based on it's sequence number.

The grid mimics the physical rack: 16 rows by 5 columns. Inputs are bidirectional. The user can type a number to highlight a cell, or click/tap on any cell to get the sequence number. The application is client-side for realtime feedback as the user interacts with the page.

Under the hood, it's Rust compiled to WebAssembly and served statically to deliver native-like speed without a backend.