BUTTONSCOPE
Methodology
We read events and values exposed by browser APIs.
Mouse timing uses performance.now and pointer events.
Keyboard tests separate repeat=true from new presses and display key and code.
Controller tools read buttons, axes and mapping through Gamepad API.
Displayed intervals are browser timing, not electrical switch timing.
Background scheduling, focus, acceleration, remapping and connection changes can affect observations.
User thresholds are exploratory settings, not manufacturer tolerances.
Keep the procedure constant, repeat observations, change one condition and consult the device maker before concluding there is a hardware problem.