The Kailh Nexus Switch is the industry’s first mass-produced switch to integrate a mechanical metal contact leaf with Hall-effect magnetic sensing within a single unit. The core engineering challenge lay in preventing mutual interference between the magnet’s magnetic field and the physical structure of the contact leaf when they coexist within the same switch stem space. Kailh’s solution was «physical isolation combined with functional decoupling»: the leaf and the magnet are positioned in separate zones within the stem—the leaf handles tactile feel and mechanical actuation, while the magnet handles Hall-effect sensing, ensuring neither interferes with the other. However, this design comes with a structural trade-off: currently, the Nexus Switch can only enable dual-mode switching on specialized PCBs (such as the Lofree HYZEN); installing it in a standard mechanical keyboard or a dedicated magnetic-switch keyboard prevents it from fully utilizing the potential of its dual «hearts.»
I. Why a «Two-in-One» Design?
I årevis har mekaniske brytere og magnetiske brytere okkupert parallelle spor. Mekaniske brytere er avhengige av metallbladkontakt for aktivering, og tilbyr taktile støt og den karakteristiske lyden av bladet, men de lider av faste aktiveringspunkter og levetid begrenset av slitasje på kontaktpunkt. Magnetiske brytere bruker Hall-sensorer for å oppdage endringer i magnetfelt, og støtter funksjoner som Rapid Trigger, DKS, SOCD, 0.01mm-nivå aktiveringspresisjon og overlegen holdbarhet, men de gir en lineær følelse og mangler fysisk taktil tilbakemelding.
Svakhetene til den ene er nettopp styrkene til den andre. Kailh valgte å kombinere disse to banene i en enkelt bryter: metallbladet bevarer skriveteksturen og bunn-ut-tilbakemeldingen til en mekanisk bryter, mens magneten og Hall-sensoren gir de justerbare reise- og esportsorienterte funksjonene til en magnetisk bryter.
II. Interferensproblemets natur
Plassering av både en magnet og et kontaktblad inne i samme bryterstamme introduserer flere risikoer for fysisk interferens.
Magnetisk kretsinterferens er den primære bekymringen. Kontaktbladet er laget av en kobberlegering; mens kobber i seg selv er ikke-magnetisk, deformeres bladet under aktivering. Hvis bladets posisjon eller bevegelsesbane bringer det for nær magneten, kan det teoretisk forårsake mindre forstyrrelser i magnetfeltfordelingen, og dermed påvirke Hall-sensorens nøyaktighet i avlesning av kjøreposisjonen.
Konkurranse om innvendig plass er det andre problemet. I tradisjonelle mekaniske brytere har rommet i stammen kun plass til metallkontaktbladet og fjæren, mens i magnetiske brytere rommer det bare magneten og fjæren. Nexus Switch krever imidlertid at begge systemene holdes innenfor samme stamme, samtidig som standard MX-bryterdimensjoner og en total kjøreavstand på 3.5mm opprettholdes.
Akustisk interferens utgjør en tredje utfordring. Tilstedeværelsen av kontaktbladet endrer det interne akustiske kammeret; når magneten og bladet eksisterer side om side, endres lydprofilen og resonanskarakteristikkene.
III. Kailhs løsning: Fysisk isolasjon og funksjonell frakobling
Under utviklingen av Nexus Switch etablerte Kailh to klare tekniske mål: å sikre ingen interferens mellom magnetens magnetfelt og kontaktbladet, og opprettholde dimensjonskompatibilitet til tross for integrering av doble utløsende funksjoner.
An analysis of the Nexus Switch’s structure reveals a solution characterized by «separation and decoupling.» The stem is made of POM and contains a Neodymium-Iron-Boron (NdFeB) permanent magnet to generate the field required for the Hall effect sensor. Meanwhile, the contact leaf assembly (comprising a moving copper alloy leaf and a stationary leaf) is housed in a separate zone on the side of the stem, handling mechanical actuation and bottom-out feedback. These two systems are physically separated; the contact leaf’s movement path avoids the magnet’s effective field zone, and the magnet’s field does not extend to the contact points of the leaf.
Crucially, the functions are decoupled. The contact leaf is responsible solely for «tactile feel» and «mechanical conduction,» while the magnet handles «magnetic sensing actuation.» In magnetic switch mode, the contact leaf plays no role in signal generation; in mechanical switch mode, the magnet does not participate in trigger detection. Each system operates independently, eliminating logical conflicts—such as the need for arbitration between simultaneous contact-based and magnetic signals.
IV. Operasjonell logikk i dual-mode-systemet
It is important to clarify a common misconception: the «dual-mode» capability does not mean the switch itself automatically toggles between modes. Instead, the operating path is determined by the PCB on which the switch is installed. When mounted on a standard mechanical keyboard, it functions as a mechanical switch (using contact leaf conduction); when mounted on a standard magnetic keyboard, it theoretically utilizes the Hall effect path (though pin compatibility issues may arise). What truly enables the simultaneous availability of both systems is the dedicated PCB found in the Lofree HYZEN. The HYZEN board supports both mechanical and magnetic switch architectures, allowing for board-wide mode switching via a physical toggle on the keyboard. When switched to the mechanical mode, the system relies on metal leaf contact, with a fixed actuation point of 1.3mm; when switched to the magnetic mode, it utilizes Hall-effect sensing, allowing the actuation point to be customized between 0.01mm and 3.5mm via software, while also supporting features like Rapid Trigger and DKS.
V. Strukturelle avveininger
The «physical isolation + functional decoupling» approach of the Nexus Switch solves interference issues but entails several unavoidable trade-offs.
PCB compatibility is the most immediate issue. Magnetic switch PCBs lack the pinholes required for mechanical switch leaf contacts; installing the Nexus Switch onto a magnetic switch keyboard necessitates trimming the leaf contact pins, which permanently disables the mechanical mode. Conversely, when installed on a standard mechanical keyboard, the lack of corresponding sensing circuitry for the magnet and Hall sensor renders the magnetic switch functions inoperable. In essence, the Nexus Switch is currently a «specialized switch» compatible only with the HYZEN keyboard.
Old issues associated with mechanical modes have resurfaced. Metal contacts bring about problems such as contact bounce, the need for debouncing strategies, and long-term oxidation—issues that have plagued mechanical switches for decades. While the era of pure magnetic switches had shed this «baggage,» the Nexus Switch reintroduced it to achieve a specific typing feel. Some early HYZEN users reported double-clicking issues in mechanical mode, a problem rooted in the physical contact characteristics of the metal leaf.
Challenges in acoustic tuning. The coexistence of the metal leaf and the magnet encroaches upon the internal acoustic space of the switch. Some reviews describe the Nexus Switch’s sound as a «muffled, Hi-Fi ‘mahjong tile’ sound»—a positive attribute derived from the metal leaf—while others criticize the sound quality, indicating inconsistencies in acoustics across different production batches or keyboard structures.
VI. Spesifikasjoner
Nexus Switch er for øyeblikket kun tilgjengelig i én spesifikasjon:
Driftskraft: 40 ± 10 gf
Aktiveringsbevegelse: 1.3 ± 0.4 mm (justerbar i magnetisk brytermodus; fast i mekanisk brytermodus)
Total reise: 3.5 ± 0.2 mm
Innledende magnetisk fluks: 90 ± 15 Gs
Magnetisk fluks nederst ut: 480 ± 40 Gs
Mekanisk levetid: 80 millioner sykluser; støtter hot-swapping (kan ikke loddes); driftstemperatur: -10°C til +70°C.
