No new features here — just making an existing system more reliable and easier to interface with.
The goal was to design a compact key-like device that fits into existing machines with a very specific mechanical footprint, while providing a clean and repeatable electrical connection.
The housing geometry was entirely derived through reverse engineering: every dimension, alignment point, and insertion behavior had to match the host machine closely enough to guarantee consistent positioning and reliable operation. For the contacts, pogo pins were the natural choice — robust, tolerant of small misalignments, rated for many insertion cycles. An integrated LED gives immediate visual feedback on status.
What’s interesting about this kind of project is that the challenge isn’t inventing something new. It’s designing something new that fits perfectly within the constraints of something old.