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Higher Education & Research

The scanner read every barcode except theirs

They had no way to say who was holding what, and a barcode scanner that would not decode their own label format — the capability was licensed separately and they had declined to buy it. Writing the decoder in C cost less than the licence and made the rest of the system possible.

Verified engagement. Every claim on this page traces to a document, a publication or a system somebody can open, and we can arrange a direct reference call for a shortlisted engagement. The work was done by the engineers who founded this firm, in most cases before the firm existed, which is why the dates below predate it. Client names and identifying details are withheld under NDA unless the client has agreed to be named.

Client
A university-affiliated research complex
Duration
About four weeks
Team
1 engineer
Year
2024

The situation

What we walked into.

Inventory was not tracked in any system. Items left and came back, and the question of who currently held a given thing could only be answered by asking around.

They had settled on their own barcode format rather than paying for a commercial one. That was a reasonable commercial decision and it had a consequence nobody had priced: the off-the-shelf scanner would not decode the format, because decoding it was exactly the capability the vendor licensed separately.

So the blocking constraint was commercial rather than technical. Every path forward involved either paying for the licence, changing the label format, or reading the barcodes themselves.

Approach

How it was sequenced.

Each step had to be independently valuable. That constraint is what let the client stop at any point without being stranded.

  1. Step 01

    Decide what tracked actually means

    Not a catalogue of things owned, which is what inventory usually gets built as. The question being asked was who has this right now, so the record is a check-out against a person and a check-in that closes it — and the item's identifier is unique in the database, because two rows for one physical object makes the answer meaningless.

  2. Step 02

    Decode the labels ourselves

    Firmware written in C, on Linux, to read the scanner's output and decode their format directly. It was cheaper than the licence and it removed the constraint permanently rather than renting relief from it — and it meant the label format stayed theirs to change.

  3. Step 03

    Build the system around the scan

    A web application behind single sign-on, reachable from the internal network rather than published, with check-in and check-out driven by the scanner rather than by typing. The interaction is a scan because anything slower does not get used.

  4. Step 04

    Hand it over properly

    The repository was transferred to the client, with a written handover covering what to change first: move off SQLite before production, add the test suite, and the specific columns not to touch and why. It is now maintained by them.

What was built

The parts that mattered.

  • The blocking problem was a licence, not a technical limit — and the cheapest fix was to write the decoder.
  • Custom label format stayed under the client's control rather than a vendor's.
  • Check-out is against a person, so the system answers who has it, not merely what exists.
  • Second engagement for this client, after the vehicle data acquisition work.
  • Handed over with the repository transferred and the next steps written down.

Results

Measured, with the method stated.

Every figure below has a defined measurement window and a comparable baseline. Numbers without those are just adjectives.

Tracked in and out, against a holder
Every itemTracked in and out, against a holderThe question that could previously only be answered by asking around is now a lookup.
Purchased to read their own labels
No licencePurchased to read their own labelsThe decoder was written once. The alternative was a recurring cost for permission to read a format the client had designed themselves.
Repository handed to the client
TransferredRepository handed to the clientOwnership moved with the code, along with a handover document naming what to change first. The firm's exit terms describe this arrangement; this engagement is one that actually ended that way.

Built with

  • Ruby on Rails
  • C firmware on Linux
  • Barcode decoding
  • OAuth single sign-on
  • Tailwind CSS
  • SQLite

Services involved

More work

Related engagements.

Next step

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