Dustin Gamble

← Back to projects

Fast Mechanical Safe Decoder

A rapid mechanical concept for decoding combination-safe behavior with physical feedback and iteration.

Problem / context

Many lock mechanisms hide useful physical signal behavior behind interfaces that are hard to observe consistently by hand. The goal for this project was to build a compact electromechanical test rig that could automate dial motion, capture signal cues, and speed up repeatable experimentation.

Approach

The build combined fast mechanical prototyping with embedded control software:

The original sketch implemented a keypad-driven 3-stage search flow:

  1. Stage 1 sweep to identify strongest third-number contact signature.
  2. Stage 2 sweep with stage-1 candidate fixed to identify the best second-number candidate.
  3. Stage 3 sweep with first two candidates fixed, checking opening behavior with timeout-based detection.

Auto-run mode chained all three stages, while manual commands supported quick nudges and spot checks. This kept tuning practical during hardware iteration.

The linked code lab preserves the handwritten baseline (SafeTherapy_v0.33.ino) and documents a suggested cleanup starter (SafeTherapy_v0.34_suggested.ino) to improve readability and future maintainability without losing the original behavior.

Outcome / lessons

The project demonstrated that mechanism-heavy experiments move much faster when motion control, sensing, and logging are tightly integrated. It reinforced a recurring engineering theme: testability and setup time have a first-order effect on iteration speed.

It also showed the value of preserving historical code while creating a cleaner forward path. Keeping the original implementation intact and documenting a modernization path made the work easier to revisit and improve later.

Links