Trigger Linearity Test — Smooth 0→100% Response Curve

The tool reads what the sensor reports to the browser, not what the trigger feels like under your finger. The mechanical pivot can travel smoothly while the carbon track or Hall sensor underneath is reading in jumps — your finger glides cleanly through a region where the sensor is skipping past damaged contact, so the pull feels fine but the score reflects the actual sensor output. This is one of the most common failure patterns on lightly used controllers, especially when a single trigger has had heavy use in one game and the other has not. The fix is usually a clean of the trigger pivot and a system-level recalibration before any harder step.

A standard trigger uses a potentiometer — a small carbon-coated resistive strip with a metal wiper that slides across it as you pull. The position of the wiper changes the resistance, which the controller reads as a value between 0 and 1. The problem is mechanical wear: the wiper drags across carbon over thousands of pulls, eventually damaging the coating and producing the stepped, plateaued, or jumping curves you see in the tool. A Hall-effect trigger replaces all of that with a magnet on the trigger arm and a magnetic field sensor on the board. Nothing touches anything, so nothing wears. Hall triggers cost more up front but the analog response stays linear for the life of the controller. Several modern third-party pads — 8BitDo Ultimate, GameSir Cyclone, Scuf and Battle Beaver builds — ship with Hall triggers as standard.

Firmware updates occasionally reset the controller's stored calibration values for triggers and sticks. The mechanical hardware hasn't changed, but the firmware no longer knows exactly where "fully released" and "fully pressed" sit on this specific unit. The result is a curve that looks compressed — peak values reading 0.92 instead of 1.0, or a rest value sitting at 0.04 instead of 0. Running the system-level trigger recalibration (Step 2 in the fixes section) restores the original score in a single pass. This is worth trying before any other diagnostic if a previously clean controller suddenly tests poorly after a console update.

Probably not. The PS5 DualSense's adaptive triggers contain a small motor and gear assembly that physically varies the resistance and travel of the trigger under game control — games like Returnal and Gran Turismo push tension changes through the triggers as part of gameplay. When those games close, the adaptive hardware does not always reset to a perfectly neutral state. Subsequent pulls in this tool may feel stiffer or softer than usual until the trigger has been cycled fully a few times. The linearity score should still be high if the sensor itself is healthy; the variation you feel is the adaptive hardware, not a fault. If the score is also degrading, then the sensor underneath is wearing the same way any other DualSense trigger does, and the adaptive feel is unrelated.

Yes — the trigger return spring is the most overlooked cause. A weakened or partially seated spring lets the trigger arm catch and release unevenly as it travels, which produces a curve with brief flat regions or visible wobble even though the sensor itself is fine. You can usually feel a bad spring: the trigger feels slightly notchy or fails to return fully on its own. The fix is to open the controller, check that the spring is correctly seated in its pivot pocket, and replace it if it has lost tension. Replacement springs cost a couple of dollars and are part of most trigger module kits, so a single parts order usually covers either fix.

No. The score compares the shape of your pull against an ideal linear line scaled to your peak value, so a slow clean pull and a fast clean pull produce the same result. What pull speed does affect is the visual readability of the trace on the graph — a very fast pull compresses the trace into the left side of the graph and makes stepping harder to see at a glance, while a slow pull spreads it across the full width. For diagnostic confidence, especially when looking for small plateaus, deliberately slow pulls are easier to read visually. The score itself is unchanged.

The Switch Pro Controller works as long as the browser detects it — connect it over USB or pair via Bluetooth and the trigger picker should respond. The catch is that the Switch Pro's ZL and ZR are digital triggers, not analog ones. They report as 0 or 1 with nothing in between, so the linearity test isn't meaningful — the curve will look like a vertical line jumping from rest to fully pressed. Joy-Cons have no analog triggers at all; their ZL and ZR are also pure digital buttons. The test is built for controllers with proper analog triggers: DualShock 4, DualSense, Xbox One, Xbox Series, and most modern third-party PC pads.

Heavy-use triggers — R2 or RT on a pad used mainly for shooters or racing — typically start showing measurable wear at around 12 to 18 months of daily play, and serious degradation at the two-year mark. Light-use triggers can stay clean for the full lifetime of the controller. The wear is mechanical and proportional to use, so a pad that mostly plays platformers will outlast one that mostly plays Call of Duty or Forza by a factor of two or three on trigger life specifically. Hall-effect triggers don't follow this curve at all — the sensor reads the same after five years as it did on day one because there is no physical contact between the moving and the sensing parts.

The honest answer depends on the rest of the controller. A pad where only one trigger has gone is well worth a five to fifteen dollar replacement module and a 20-minute swap — you keep the pad you're used to, including any stick precision and button response you've trained on. A pad where multiple components are degrading — both triggers, stick drift, a sticky face button — is approaching end of life regardless, and replacement is the rational call. If you're going to replace, look at controllers shipping with Hall-effect triggers from the factory; the cost difference is small and the trigger wear cycle ends. For a pad still under manufacturer warranty, the path is always claim first, repair later — manufacturers replace pads under warranty without charge and the support process is usually fast once you have screenshot evidence of the failure.