Quick Links
There is a lot to consider when purchasing a gaming keyboard. You need to choose between mechanical and membrane, full-size and tenkeyless, wireless or wired, and the list goes on.
However, there’s one essential keyboard feature that tends to be overlooked: anti-ghosting.
What Is Anti-Ghosting, and Why Is It Essential in a Gaming Keyboard?
To explain what anti-ghosting is and why you need it in a gaming keyboard, we’ll need to talk about ghosting. Ghosting is a design flaw in keyboards that causes an unintended or “phantom” key to be registered when multiple keys are pressed at the same time. It is an issue that has gotten rarer with time but is still prevalent in cheap, poorly-designed keyboards.
Electronically, a keyboard works via a combination of a key matrix, the keyboard controller, and supporting firmware. The key matrix is a grid of conductive traces placed on a membrane sheet (membrane keyboards) or a printed circuit board (mechanical keyboards) and arranged in rows and columns.
Each key on the keyboard is placed at the intersection of a row and column. The keyboard controller scans the key matrix for key presses by sending a small electrical signal down each column in turn and checking to see if any row is active. This allows the controller to detect when keys are pressed. The rate at which the controller scans the matrix is called thekeyboard’s polling rateand is measured in Hertz (Hz).
This polling method usually works well, but when three or more keys are pressed concurrently across different rows, it can cause phantom keys to be detected. For example, pressing “W”, “E”, and “D” at the same time could lead to “S” being detected.
It is easy to see how this can affect gameplay. Imagine playing a high-octane game and an accidental grenade toss blows your teammates to bits or your game character comes to a sudden standstill in the heat of battle, because the keyboard controller detected a phantom key press.
Anti-ghosting is a keyboard feature that does exactly what the name implies. It prevents phantom keys from being registered. There are three ways to implement anti-ghosting in a keyboard: blocking, diodes, and capacitive sensing.
Blocking, commonly mislabeled as ghosting itself, divides the keyboard into specific matrices, i.e. sections of keys that can function at a time. Blocking is less expensive to implement than diodes, which means it is much more common in anti-ghosting keyboards. Keyboards that use diodes are more pricey, but they allow for more key presses and even n-key rollover. Capacitive keyboards are easily the most expensive, but they offer other advantages besides anti-ghosting, such as extended durability and quick response times.
Most built-in keyboards implement blocking. If you are using one, you can see it in action by holding down the keys “A”, “S”, and “Z” on your keyboard. The keyboard controller will ignore the “Z” key to prevent “X” from being registered.
As mentioned earlier, most modern keyboards use anti-ghosting in one form or another, but you can still come across ghosting in vintage or poorly-made keyboards. In all its forms, anti-ghosting ensures registered key presses originate from the user and no phantom signals are sent to the controller.
Ghosting is primarily a problem with the alphanumeric keys on the keyboard. Other sections, including modifiers (Ctrl, Shift, Alt, Fn), are not usually affected.
Anti-Ghosting vs. N-key Rollover
These two terms are often used interchangeably but mean different things.
N-key rollover (NKRO)means all keys can be pressed simultaneously, while anti-ghosting implies that multiple keys can be pressed at the same time without producing a phantom key. A keyboard can have anti-ghosting without NKRO (i.e. using blocking) but it is impossible to implement NKRO without anti-ghosting.
How to Test for Keyboard Ghosting
you’re able to use your computer’s default text editor to check for keyboard ghosting or anti-ghosting. All you need to do is hold down a combination of two keys in one row of the keyboard and then press any key directly below the ones you have held down. Also, there are online ghosting demonstration tools you can use, such asMicrosoft’s Anti-Ghosting Demoand theMultiKeyDisplay project.
You don’t need to break the bank for an anti-ghosting keyboard, there are severalbudget-friendly optionsto choose from. If you’d rather not buy a new keyboard for anti-ghosting, you may customize your key bindings in-game to avoid any combinations that can cause ghosting.
