Mouse & Hardware Terminology Glossary
Clear, engineering-grade definitions of essential gaming peripheral specifications, optical sensor dynamics, switch mechanical chatter, and sensitivity mathematics.
Polling Rate (Hz)
The frequency (in Hertz/seconds) at which a USB gaming mouse reports its cursor position and button input states to the computer operating system. Standard mice report at 125Hz (8ms latency), gaming mice at 1000Hz (1ms latency), and ultra-high polling mice at 2000Hz–8000Hz (0.5ms–0.125ms latency).
CPI & DPI
CPI (Counts Per Inch) and DPI (Dots Per Inch) measure optical mouse sensor hardware sensitivity — specifically how many counts or steps the sensor registers per physical inch of movement across the mousepad surface.
eDPI (Effective DPI)
Effective Dots Per Inch (eDPI) is calculated by multiplying physical Mouse DPI by In-Game Sensitivity setting (eDPI = Mouse DPI × In-Game Sens). It provides a standardized metric for comparing mouse sensitivity across players using different DPI hardware presets.
cm/360 (Turn Distance)
The physical horizontal distance in centimeters required to rotate your in-game 3D camera a full 360 degrees. Independent of DPI, resolution, or game engine, it represents the universal baseline for physical aim muscle memory.
Switch Debounce Delay
Debounce delay is a firmware timer or algorithm designed to ignore secondary mechanical electrical chatter (bounce) created when physical metal contacts snap together inside a mechanical switch.
Optical vs Mechanical Switch
Mechanical switches rely on physical metallic leaf contacts that oxidize and bounce over time. Optical switches use an infrared light beam interrupted by an internal shutter, making them far less prone to contact bounce, oxidation, and double-clicking.
Switch Chatter (Contact Bounce)
Microscopic electrical oscillations occurring when mechanical switch contact leaves collide upon press or release. If bounce duration exceeds the firmware debounce window, an unintended double-click is registered.
CPS (Clicks Per Second)
Clicks Per Second (CPS) measures how many times a user can actuate the primary mouse button in a 1-second window. Testing techniques include Regular Single Clicking, Jitter Clicking, Butterfly Clicking, and Drag Clicking.
NKRO & Key Rollover
N-Key Rollover (NKRO) indicates that a mechanical keyboard hardware controller can register every key pressed simultaneously without key ghosting or missed inputs.
Rapid Trigger (Hall Effect)
Rapid Trigger dynamically resets key actuation the exact millisecond a key switch moves upward, without needing to pass a static fixed reset point.
Angle Snapping
Hardware sensor prediction algorithms that artificially smooth out slight diagonal deviations, forcing cursor movement into rigid horizontal or vertical lines.
Sensor Jitter & Noise
Unintended erratic micro-movements registered by an optical sensor when tracking on high DPI settings, uneven mousepad weave textures, or around microscopic dust on the lens.
Motion Smoothing
Firmware averaging applied across consecutive coordinate packets to suppress sensor ripple at high DPI levels (typically above 3200 DPI on older sensor generations).
Lift-Off Distance (LOD)
The vertical height in millimeters at which an optical sensor stops tracking the mousepad surface when the mouse is physically lifted by the player during repositioning swipes.
Rotary Encoder (Scroll Wheel)
The internal electromechanical or optical dial sensor that translates rotation of the mouse scroll wheel into directional step notches (deltaY offsets).
Yaw Angle
The game engine multiplier angle constant used to convert mouse count inputs into 360-degree horizontal camera rotation angles in 3D FPS game engines.
Pointer Lock API
A W3C browser standard that hides the desktop cursor, locks pointer coordinates to an element, and delivers raw unaccelerated relative motion counts (movementX/movementY).
Coalesced Pointer Events
An advanced browser API (event.getCoalescedEvents()) providing access to all intermediate micro-movement packets received by the OS between animation frame render ticks.
Static vs Dynamic Friction
Static friction is the force required to break a mouse out of a standstill. Dynamic friction is the sustained resistance encountered while gliding across the mousepad.
Microsecond Timestamp (Δt)
High-resolution monotonic time intervals sampled via performance.now() to measure exact sub-millisecond deltas between hardware actuation packets.