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What are Hall-effect switches?

Close-up of a keyboard switch with a magnet and removed keycap
AI-generated editorial illustration · Conceptual scene

A Hall-effect keyboard switch senses a keypress magnetically instead of with a physical metal contact. A magnet in the switch moves toward a Hall sensor on the keyboard's circuit board, and the sensor reports the changing magnetic field as a continuous position rather than a simple on/off. Wooting, which makes Hall-effect keyboards, describes the difference this way: where traditional mechanical switches use physical contact points, its Lekker switches use magnetic sensors to detect the exact position of a keypress.

How the sensor works

The physics is 19th-century. Allegro MicroSystems, a Hall-sensor manufacturer, explains that Edwin Hall discovered in 1879 that a voltage develops across a current-carrying conductive plate when a magnetic field passes through it at right angles. A Hall sensor measures that voltage. In a keyboard, the magnet gets closer to the sensor as the key goes down, the field at the sensor grows stronger, and the keyboard's firmware turns the reading into a key depth.

Two consequences follow from that design:

  • Nothing touches to register a press. There are no contact points to close; what the keyboard reads is a magnetic field.
  • The switch depends on the board. Because the sensor sits on the circuit board rather than in the switch, a magnetic switch needs a board with a sensor under each key. That follows from the design; check a keyboard's compatibility list before mixing switches across boards.

What the analogue signal unlocks

Because the keyboard knows how far down each key is, not just whether it is pressed:

Feature What it does
Adjustable actuation The trigger point can be set per key. On the Wooting 80HE it can be set anywhere from 0.1 mm to 4 mm, with 0.1 mm precision
Rapid Trigger Wooting's name for a key that resets and activates the instant it moves, so a release registers immediately and the key can fire again without first travelling back to a fixed reset point
Analogue input Software can read key depth as a gradual value, for example to drive a joystick axis in a game

These features come from the sensing method and the firmware together. Two keyboards with the same kind of sensor can behave differently because their firmware reads the signal differently.

Hall effect vs TMR

A newer kind of magnetic sensor, TMR (tunnel magnetoresistance), is now sold in keyboards as an alternative. Both detect the same moving magnet; they differ in what they measure. In Wooting's words, a Hall sensor "produces a voltage reading" based on the strength of the field, and a TMR sensor "produces a resistance reading".

Hall effect TMR
What the sensor outputs A voltage A change in resistance
Power draw (Wooting's testing) Higher 5 to 10 times lower than Hall-effect sensors after signal boosting
Sensor price (Wooting's quotes) Similar Roughly the same price as its Hall sensors in Wooting's initial quotes

On signal quality the two manufacturers disagree, and each sells the technology it defends: Keychron says its magnetic switches use TMR, and Wooting sells Hall-effect keyboards. Keychron says TMR's resistance change comes "with far higher signal amplitude than Hall". Wooting says pre-2020s Hall sensors had measurably worse noise performance than TMR, but that the gap has largely closed, and concludes that TMR's perks have not shown gains in keyboard accuracy, precision or speed.

What the evidence supports so far: no independent measurement in these sources shows one sensor making a keyboard more accurate. The one quantified difference, lower sensor power, comes from a single manufacturer's testing. That it extends battery life on a wireless keyboard is a reasonable inference, not a measured result: none of these sources says how much of a keyboard's total power the sensors use.

Check the label

"HE" in a product name is used loosely. Keychron's own blog states that its magnetic switches have always used TMR technology, from the first Keychron Q1 HE onward, while its K3 HE product page describes that keyboard's switches as powered by Hall Effect sensing. When the sensor type matters to you, look for it in the specifications rather than in the model name, and expect that even a manufacturer's own pages may not agree.

Durability

Wooting rates the 80HE's switches for 100 million or more keypresses with no degradation in performance. That is a manufacturer's rating, not a measurement made by this index, which does not test keyboards.

In the index

Two keyboards in the index list magnetic switches in their verified specifications: the Wooting 80HE, with Lekker switches, and the Keychron K3 HE, recorded from its product page as magnetic analog (Hall effect), a label Keychron's blog contradicts, as noted above. Manufacturer figures on this page were checked against their pages on 29 September 2026. Their specifications side by side are on the Keychron K3 HE vs Wooting 80HE page.

Sources

END OF ANALYSIS

In the Fathom index

Keyboards in the index that list Hall-effect switches. Matched on each item's own record and sorted A–Z, not by merit.

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