The Hall effect is a reaction between magnets and electricity. When a magnet moves closer to an electrical current in a conductor, it moves the electrons, and with this, the distance between the magnet and conductor can be measured and reported back to your computer. The magnet sits in the switch’s stem, and the Hall effect sensor is on the printed circuit board of the keyboard. Your computer can interpret this information to register a keypress once the key is at a certain distance.

That’s different from a mechanical switch on a mechanical keyboard, which physically makes contact when depressed to register a keystroke. We explain Hall effect in greater detail in this story.

What Are Hall Effect Sensors and How Do They Work?

More and more keyboards and video game controllers employ Hall effect sensors, but what exactly is this technology? We break it down.

By Henri Robbins

Polling rate is likely one of the most prominently displayed details on any Hall effect keyboard, purely because the large numbers emphasize one of the most important aspects of these keyboards: Speed. Whether a keyboard has a 1,000- or 10,000-Hz polling rate, this number represents how many messages are sent from the keyboard to the PC every second. For example, a keyboard with 1,000-Hz polling will send 1000 messages every second. Most office equipment operates at 125 Hz. In high-performance gaming, a higher polling rate is almost always preferred, since more information being transferred reduces the chances of a movement or keypress not being recognized immediately. That said, 1,000 Hz is more than enough—you won’t really notice many benefits of going higher.

Software has also proven to be make-or-break with Hall effect keyboards. Nearly every HE keyboard relies on software to make adjustments and customizations, so this is a critical aspect of a good keyboard. In evaluating this, I consider ease-of-use, functionality, and the scope of customization. Software that makes customization difficult, has any stability issues, or uses a lot of processing power will just make life more difficult.

Build quality is important for both obvious and less-obvious reasons. It’s important for a keyboard to feel good to type on and to have a rigid construction, but it also matters how good quality control is with switches and how well-tuned the stabilizers are. Because Hall effect keyboards rely on magnets and sensors to register keypresses, a misalignment of a magnet or sensor can cause keypresses to register at incorrect distances without any obvious tells, which can cause issues with your performance when gaming.

Actuation distance is typically measured in millimeters and indicates the distance a key has been pressed. Hall effect keyboards usually measure to a tenth of a millimeter, although sometimes they extend out to a hundredth of a millimeter. Most keyboards will measure this from the top resting position, at zero millimeters. The bottom-out distance, where the key is fully pressed, will typically sit between 3 and 4 millimeters. The distance between the top and bottom of the keypress is the travel distance, and the maximum travel distance possible is determined by the switches you’re using and the keyboard itself. If you have a switch with a 4-mm travel distance and a keyboard that only measures up to 3.5 mm, you’ll either be limited to a shorter actuation distance, or will run into compatibility issues that make typing inconsistent.

The largest benefits of a Hall effect keyboard come from the switches, which utilize a magnet to determine how far a key has been pressed down. This allows the keyboard to recognize not only the binary signal of “yes” or “no” that most keyboards send, but also to receive a measurement of distance. With this, you can set a key to register an input at whatever distance you want, from the very top of the keypress to the bottom. You can fine-tune the sensitivity of your keys to your preference.

This system has multiple other uses. The most common, “rapid trigger,” allows for faster rapid keypresses by dynamically changing the actuation point of the key. In essence, instead of needing to press a key a certain distance for it to register a keypress, your keyboard will register an input whenever the switch starts to be pressed down. This means you don’t have to wait for a key to be fully released before you can press it down again, thus creating a faster response.

One switch can also be programmed to have multiple inputs based on how far it is pressed down. This is typically used for walking and running in first-person shooters, where a half-press is walking and a full press is running, but with the right software, it can also be used for steering in a racing game or other joystick controls that need multiple degrees of input.

On paper, Hall effect keyboards perform better by every metric imaginable compared to mechanical keyboards. However, performance is only a small part of what makes a keyboard good. More than anything else, I’ve found the most important part of a keyboard to be how it feels to use. This is where Hall Effect keyboards can potentially fall short. They are a relatively new technology, still on the cutting edge, and as a result, Hall effect keyboards have nowhere near the aftermarket support and community around them that standard mechanical keyboards have, and there are far fewer options for customization.

When building a mechanical keyboard, there are hundreds of cases, thousands of switches, and tens of thousands of keycaps to choose from. Meanwhile, there are only a handful of Hall effect keyboards on the market, most of which use either proprietary or semi-proprietary switch designs. Around half of the Hall effect keyboards I’ve tested use Gateron switches, and even among those, two prominent types of switches are not cross-compatible with one another. You’ll be limited to only changing the keycaps on the majority of Hall effect keyboards unless you do a lot of research or are willing to undergo some trial and error.

Also, since Hall effect switches have customizable actuation points, this means tactile or clicky switches with a distinct bump are far less common. There have been a few, such as the AEBoards Raed HE switches, which are compatible with Hall effect keyboards from Wooting and Geon, along with some other brands.