About

This is not merely a visualization tool; it is a forensic utility for input devices. In competitive gaming (eFPS, Fighting Games), hardware integrity is as critical as reflex speed. A standard potentiometer-based analog stick has a finite lifespan, often degrading into "drift" or non-linear response curves within 400 - 600 hours of use. This application interfaces directly with the browser's Gamepad API to expose the raw data stream typically hidden by game engines.

We provide advanced metrics such as Circularity Error Rates (determining how perfectly a stick traces a circle) and Polling Rate Jitter (measuring the stability of the connection). This allows users to distinguish between network lag, software configuration issues, and physical sensor failure. Whether you are validating a new Hall Effect controller or diagnosing an old DualShock, this tool provides the raw mathematical truth of your hardware's performance.

Formulas

Circularity Error Calculation: To test the quality of an analog stick's range, we calculate the deviation of the magnitude from 1.0 during a full rotation. A perfect stick traces a circle where x² + y² always equals 1.

Error_avg = n∑i=1 | √x_i² + y_i² − 1 | × 100%

Drift Magnitude: The vector distance from the true center (0,0) when the stick is mechanically released.

Drift = √(x − 0)² + (y − 0)²

Reference Data

Metric	Definition	Ideal Range	Diagnostic Relevance
Polling Rate	Frequency of data updates sent to the host.	125 - 1000 Hz	High rates reduce input latency but require stable USB/Bluetooth connections.
Circularity Error	Average deviation from a perfect unit circle during rotation.	≤ 10%	High error results in uneven acceleration in aiming (aim assist dead spots).
Axis Centering	Coordinate value when the stick is untouched.	0.0000 ± 0.05	Deviations > 0.10 indicate Stick Drift requiring deadzone adjustment.
Jitter (Variance)	Fluctuation in the time interval between updates.	< 2 ms	High jitter causes "stuttering" camera movement even with high FPS.
Resolution	Smallest detectable step of movement.	16-bit	Low resolution results in "stair-stepping" aim rather than smooth curves.

Frequently Asked Questions

Potentiometers use physical wipers against a resistive track to measure position. Friction causes them to wear out, leading to drift. Hall Effect sensors use magnets to measure position without physical contact, making them virtually immune to drift and significantly more durable.

Browsers (Chrome/Firefox) throttle the Gamepad API polling to match the screen refresh rate (typically 60Hz or 144Hz) or to save resources. Furthermore, Bluetooth connections are inherently less stable than wired USB connections, introducing natural variance (jitter) in the signal.

Not necessarily. Many official controllers (like older Xbox pads) use a "squarish" gate, resulting in higher error rates at the diagonals. However, if you feel uneven acceleration in games, this error rate confirms the hardware limitation.

The standard Web Gamepad API currently supports basic axes and buttons. Advanced features like Adaptive Triggers or Haptic Feedback (beyond basic rumble) require proprietary drivers or specific browser flags that are not universally available in the web standard yet.