Quantum mechanics might have the solution to joystick drift

The Nintendo Switch, renowned for revitalizing portable gaming, also faces recognition for a widespread hardware problem: joystick drift. This issue, impacting millions of gamers and their gaming controllers across platforms including PlayStation, Xbox, and various third-party devices, may finally have a superior solution in tunneling magnetoresistance (TMR) sensor technology.

Drift, or controller drift as it’s often called, describes a malfunction where joysticks register phantom movements. Even without user input, this results in unwanted in-game actions. While prevalent on the Nintendo Switch Joy-Cons, joystick drift is not exclusive to Nintendo, affecting controllers from प्रमुख companies like Sony and Microsoft, as well as accessories from other manufacturers.

Hall effect sensors emerged as a potential fix for controller drift several years prior. These offered an improved approach, but an even more effective and readily adaptable technology has surfaced: tunneling magnetoresistance, or TMR. This innovation, leveraging principles of quantum mechanics and magnetism, previously transformed hard drive technology two decades ago.

Both TMR sensors and Hall effect sensors address the fundamental flaw in conventional joysticks: wear and tear inherent in their design. Current controllers for Xbox consoles (recent models), PlayStation 4 and PlayStation 5, and the Nintendo Switch all utilize potentiometers. These components rely on changing or gauging electrical resistance to function.

As highlighted by iFixit in 2021, each joystick uses two potentiometers to detect movement on vertical and horizontal axes. Inside, a semicircular carbon film strip with terminals conducts electrical current. A “wiper” component slides along this strip as the joystick moves, measuring voltage at the point of contact. Voltage variations across the strip accurately reflect joystick movement.

However, physical friction between components in potentiometers leads to degradation. The carbon film strip deteriorates over time, disrupting current flow and voltage measurement precision. Accumulation of debris, from component wear or external contaminants like dust and food particles, also contributes to inaccurate readings and joystick drift.

To combat these issues, controller manufacturers are exploring non-contact sensor technologies: Hall effect and TMR sensors. Both utilize magnetism. Hall effect joysticks, as detailed by iFixit, replace the resistive strips and wipers with magnets and sensors that operate without physical contact, based on a principle discovered by Edwin Hall in 1879.

A Hall effect sensor contains a conductive “Hall element” carrying an electrical current. Normally, electrons flow linearly. However, a magnetic field deflects electrons, altering their path. By measuring voltage changes in the conductor as a magnet (linked to the joystick) moves, the sensor accurately and reliably translates movements into in-game actions, eliminating wear and tear associated with potentiometers.

Hall effect sensors are not new; Sega used them in Saturn 3D and Dreamcast controllers in the mid-1990s. GuliKit revitalized their use in gaming by launching a Hall effect controller at E3 2021. However, widespread adoption is limited by the lower manufacturing costs of potentiometer-based joysticks and the higher power demands of Hall effect sensors.

TMR sensors offer a potential resolution to the limitations of Hall effect sensors. Giant magnetoresistance (GMR), discovered in 1988 by physicists Albert Fert and Peter Grünberg (Nobel Prize in Physics, 2007), is foundational to TMR. GMR involves magnetic fields influencing electron spin direction and flow in ultrathin films—conductive materials like copper or aluminum—layered between magnetic substances.

Riyan Mendonsa, senior staff engineer at Seagate, explained to The Verge that aligned electron spins between adjacent magnets (with a spacer) facilitate electron movement. Misaligned spins impede flow, altering resistance. This principle underpins both GMR and TMR.

While GMR uses a conductive material between magnetic layers, TMR employs an insulating barrier. Electrons traverse this insulator via quantum tunneling—a quantum mechanical phenomenon allowing particles to pass through barriers. This effect, governed by quantum physics equations and observed with materials like aluminum or magnesium oxide at atomic thicknesses, is key to TMR.

The significance of TMR in electronics lies in magnetic field-induced resistance changes, not tunneling itself. Before TMR, hard drives used read heads similar to speaker and microphone coils, according to Mendonsa. Seagate adopted TMR in read heads in 2005, enabling smaller and more magnetically sensitive designs.

Both Hall effect and TMR sensors can detect joystick movements using magnets without contact, but TMR sensors offer advantages.

GuliKit business director Jack He notes, “TMR sensors generally have higher sensitivity and more linear response compared to Hall effect sensors.” This allows for smaller magnets, simplifying TMR joystick manufacturing. However, leveraging sensitivity for greater accuracy depends on manufacturer implementation and backend MCU sampling precision, according to He.

TMR sensors typically consume less power than Hall effect sensors. He explains that standard controller joysticks use resistive film technology with a constant, limited power supply (around 1mA). Hall sensors can range from 0.5mA to 2mA, while TMR sensors use only 0.1mA to 0.3mA. This low power consumption enables TMR sensor joysticks to be direct replacements in existing controllers without circuit modifications, potentially speeding adoption and lowering costs.

TMR sensors also provide more stable performance across a wider temperature spectrum, beneficial for devices often used for extended periods in hand.

While major companies like Nintendo, Microsoft, and Sony have yet to adopt TMR technology, third-party manufacturers are releasing TMR joystick gamepads: PB Tails’ Crush controller, GameSir’s Tarantula Pro, and 8BitDo’s Ultimate 2 controller. GuliKit released upgrade kits in 2024 to incorporate TMR into PlayStation 5, PS4, Xbox, and Switch controllers.

Full integration of TMR technology into mainstream gaming hardware may take several years. He of GuliKit indicates that “TMR sensors are often more expensive than traditional Hall effect sensors, especially in smaller volumes. However, this cost differential is anticipated to diminish as TMR technology becomes more established.”