Engagement work

A cross-platform desktop application that connects the manufacturer’s weighing instruments to an operator’s computer — over serial cable or Bluetooth, up to several instruments at once — and delivers the live reading directly into whatever software the operator is working in, at the cursor, formatted to the operator’s own conventions: units, precision, numerals in the script the paperwork uses.

The engagement covered the whole product life: the instrument protocol work against real hardware; native Bluetooth and input-delivery layers on both macOS and Windows; an interface with honest liveness — a reading that stops arriving disappears rather than freezing; a fully offline, hardware-bound licensing system under which the manufacturer issues and audits its own customer licences without any dependence on Hameem or on connectivity; a signed, universal macOS build whose signature is verified slice by slice before release, and a Windows installer produced on its own build machine; and the verification depth — some four hundred automated tests, an integration harness that drives the real serial read loop through a pseudo-terminal, and versioned bench checklists run against the instruments themselves — that lets a small product carry commercial weight.

Under the surface it is a Rust core across seventeen crates, held to an architectural rule the build itself enforces: the core may not depend on the desktop shell at all. Bluetooth is spoken through each operating system’s own socket interface rather than a virtual serial port, because a virtual port hides a dead link behind a handle that still looks healthy. A reading goes stale in under a second and disappears with it; press the shortcut then and the application types nothing and says why, because a number that arrives late is worse than no number at all. Weights render in six units and four numeral scripts, computed in integer arithmetic so that no floating-point artefact can reach an operator’s spreadsheet, with decimal places capped at what the instrument can honestly resolve.

Delivered as a shipping product, in the manufacturer’s hands, licensed to their customers under their own control.