GEARCHECK LAB
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Touch Lab // Digitizer Coverage

TOUCH SCREEN DEAD-ZONE TEST

Sweep your finger across a coverage grid and add several fingers at once. GearCheck Lab records only browser-reported touch contacts, highlights covered regions and shows the highest simultaneous touch count observed during this session.

LOCAL INPUTTouch coordinates and coverage remain in this browser session.
Touch-only diagnostic

Coverage grid & multi-touch visualizer

WAITING FOR TOUCH
Use the touchscreen itselfDrag one finger across the whole grid in overlapping strokes. Then add more fingers to test simultaneous contacts.

How to check for touchscreen dead zones

  1. Open this page on the phone, tablet or touchscreen laptop you actually want to test.
  2. Remove obvious moisture/dirt and, if practical, compare with and without a problematic screen protector or case.
  3. Enter fullscreen, then drag one finger slowly in overlapping horizontal and vertical passes across the entire test area.
  4. Repeat corners, edges and any location that feels unreliable. A region that consistently refuses to color despite deliberate passes deserves closer investigation.
  5. Reset and repeat before concluding the digitizer has failed.

Why blank cells are not automatically faults

The grid cannot know where you intended to move your finger. A blank cell can simply mean you never crossed it, moved too quickly between sampled browser events or touched outside the test area.

A likely dead zone is a repeatable gap: you deliberately sweep the same physical area several times and the browser still reports no touch there while neighboring areas register normally.

How to test multi-touch

Place two fingers inside the test area, then add fingers one at a time. The ACTIVE count shows current browser-reported touch pointers and MAX SIMULTANEOUS stores the highest count reached this session.

The page does not assume every device should support 5 or 10 touches. Hardware, operating system and browser support determine what is exposed.

Tracking dropouts versus dead zones

A continuous drag that breaks and resumes can indicate a tracking dropout, but finger angle, moisture, palm rejection, browser gesture handling or an edge gesture can also interrupt input. Repeat the same path at a slower speed before diagnosing hardware.

What this test can and cannot see

  • It reads browser Pointer Events whose pointerType is touch.
  • It does not inspect raw digitizer electrode data.
  • It cannot test lock-screen behavior or another app's gesture processing.
  • Mouse/trackpad input is excluded from touch coverage metrics.
  • Browser UI edges and operating-system gestures can reserve part of the physical screen.

Ghost touches

If touch contacts appear here while you are intentionally not touching the screen, that is useful evidence to repeat. However, this page cannot know whether your hand, case, moisture or another physical contact caused the event, so treat it as a symptom rather than a definitive diagnosis.

Touch screen test FAQ

Can I run this with a mouse?

You can interact with the page, but mouse and pen events do not count toward the touchscreen metrics. For a real digitizer test, use the affected touch device itself.

Why can I not reach the very top or bottom edge?

Browser and operating-system UI/gesture areas can reserve parts of the display. Fullscreen helps, but some system gesture zones may remain outside webpage control.

Does 100% coverage prove the touchscreen is perfect?

No. It shows that every test-grid region reported at least one touch in this session. Intermittent dropouts, pressure-dependent faults and app-specific behavior can still exist.

Is my touch data uploaded?

No. This diagnostic uses in-page pointer events and keeps its coverage state locally for the current page session.