Scroll Wheel Test

How to use

1. Start with Steady-direction diagnostic. The default is Down / positive ΔY only: press Start, keep the surface focused, scroll steadily downward, and do not intentionally reverse direction.
2. Aim for 12 vertical browser WheelEvents, then Stop and inspect the frozen opposite-direction evidence, deltaMode units, relative magnitude outliers, and recent trace. This recommendation is not a physical-notch count or hardware standard.
3. Repeat the same controlled protocol with Up / negative ΔY only. You declare the expected browser sign; DeviceMetrik does not infer physical wheel direction from your gesture.
4. Use Explore / mixed input for deliberate direction changes, horizontal components, or trackpad exploration. It does not classify opposite-direction events.
5. Optional: choose Browser wheel-event rate with a 5s, 10s, or 30s window, then compare only the same device, input style, browser, OS settings, and setup.
6. Repeat unusual browser evidence before interpreting it. This page reports WheelEvent records, not a physical wheel or encoder diagnosis.

What the result means

• Browser wheel events are WheelEvent records, not physical wheel notches. deltaMode 0, 1, and 2 define pixels, lines, and pages for deltaX/deltaY.
• Negative ΔY is treated as the Up side and positive ΔY as the Down side for this browser diagnostic. Natural Scrolling, trackpads, and OS settings can make physical gesture intuition differ.
• Opposite-direction browser events are vertical WheelEvents whose sign conflicts with the direction declared for a controlled run. One event is evidence to repeat, not proof of encoder damage.
• Relative delta spikes are vertical magnitudes greater than 4× this run's median absolute delta magnitude when all relevant samples share one deltaMode. Mixed pixels, lines, and pages are not combined.
• Timed event rate is browser WheelEvent records divided by the run's actual elapsed seconds. It is browser cadence, not physical speed, RPM, or notches per second.
• Horizontal events may come from a tilt wheel, side wheel, trackpad, or gesture input; a WheelEvent does not identify exact hardware or guarantee that page content scrolled.

Limitations

• WheelEvent can come from a mouse wheel, trackpad, or similar input; the browser does not identify exact wheel hardware.
• deltaX and deltaY units depend on deltaMode and cannot be assumed to be pixels. Pixel-, line-, and page-based deltas are not combined into one magnitude diagnostic.
• Natural Scrolling, OS settings, touchpad inertia, smooth scrolling, browser behavior, and user gesture can affect direction and magnitude.
• A wheel event does not necessarily imply that page content actually scrolled; it can occur on an unscrollable surface or participate in other browser behavior.
• Browser events cannot reveal physical detents, encoder electrical pulses, missed physical notches, or RPM. If a physical notch or gesture produces no browser event, the page has no independent reference with which to count that absence.

Troubleshooting

The direction looks reversed

Check whether you selected the correct expected browser direction. Natural Scrolling, trackpad behavior, and OS settings can change the sign you expect. Repeat a controlled one-direction run.

I see one opposite-direction event

Repeat the same steady one-direction protocol. A single event can come from gesture variation, inertia, OS/browser behavior, or the device; it is not a hardware verdict.

The wheel seems to skip or jump

Repeat Down and Up as separate controlled runs with the same device and input style. Then try another browser, review OS/vendor scroll settings, compare another port, receiver, or wired/wireless condition where relevant, and compare another computer if available before considering manufacturer support or repair. A physical input that produces no browser event cannot be counted automatically here.

Delta values vary a lot

First check Delta unit(s). Do not compare pixel, line, and page values directly. Smooth-scroll devices and trackpads can naturally produce variable magnitudes.

I see Mixed delta units

This run contains incompatible WheelEvent units, so DeviceMetrik does not combine the magnitudes. Repeat under one consistent device, browser, and input setup.

Event rate changes between runs

Compare only the same duration, device, input style, browser, OS settings, and similar background conditions. Browser events/sec is not physical wheel RPM.

Related tools

• Mouse Test

  Use this online mouse tester to check buttons, side buttons, held states, wheel events, and pointer movement. See browser counts, hold times, movement path, and session status.

• Mouse Double Click Test

  Check a mouse for unintended repeat clicks with slow single-click screening. Inspect browser-observed intervals by button, then optionally measure intentional double-click timing.

• Mouse DPI Test

  Estimate mouse DPI/CPI from Pointer Lock movement over a measured ruler distance. Compare three trials, median, drift, input mode, and an optional configured DPI.

• Mouse Polling Rate Test

  Run a mouse polling rate test using browser-observed pointer updates. Review median Hz, event-source and coalescing context, Pointer Lock, and local aggregate history—not raw USB telemetry.

FAQ