--- key: mechanic/phone-magnetometer--family-07 type: mechanic id: phone-magnetometer--family-07 lang: en title: Passive physical controllers summary: >- A passive button or lever changes the phone sensor’s magnetic field. MagPie is a research prototype for customizable mechanical input. updatedAt: '2026-10-22' status: active url: 'https://gamemechanics.pro/en/knowledge/mechanic/phone-magnetometer--family-07/' jsonUrl: >- https://gamemechanics.pro/api/v1/knowledge/en/mechanic/phone-magnetometer--family-07.json markdownUrl: >- https://gamemechanics.pro/content/knowledge/en/mechanic/phone-magnetometer--family-07.md aliases: - Passive magnetic controllers tags: - Phone magnetometer interactions - Mechanics catalog sourceIds: - source-c4196023aaafb085 sources: - id: source-c4196023aaafb085 title: MagPie prototype url: 'https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1' verifiedAt: null relations: [] placements: - catalogId: phone-magnetometer id: family-07 title: Phone magnetometer interactions url: 'https://gamemechanics.pro/en/mechanics/phone-magnetometer/#family-07' categoryIds: - section-1 supersededBy: [] attributes: preview: updatedAt: '2026-10-22' title: Passive magnetic controllers description: >- A passive button or lever changes the phone sensor’s magnetic field. MagPie is a research prototype for customizable mechanical input. image: src: images/mechanics/sensor-magpie-figure1.webp width: 1010 height: 352 game: MagPie prototype sourceUrl: 'https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1' originalUrl: 'https://ixlab.cau.ac.kr/papers/magpie.pdf' credit: Insu Kim et al.; CHI 2025 / Chung-Ang University and Korea University rights: >- Figure 1 by Insu Kim, Suhyeon Shin, Jaemin Choi, Junseob Kim, Junhyub Lee, Sangeun Oh, Eunji Park and Hyosu Kim. CC BY-NC 4.0: https://creativecommons.org/licenses/by-nc/4.0/ . Cropped from PDF page 1 to the figure and converted to WebP. Figure includes third-party application imagery; Stardew Valley graphics © ConcernedApe. Excluded from portal MIT and CC BY 4.0. caption: 'MagPie: magnetic buttons and a proposed gamepad scenario' alt: 'MagPie: magnetic buttons and a proposed gamepad scenario' markers: - x: 83 'y': 43 label: Moving the mechanical module changes its magnetic signature tips: - Test magnetic interference and combinations of simultaneous inputs. examples: - title: MagPie prototype url: 'https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1' endsAt: null provenance: >- Original editorial design catalog consolidated from project discussions on 2026-10-20. Complete discussion item lists and contextual limitations are preserved; linked primary sources support specific techniques, not the entire classification. English translation was prepared with machine assistance and editorial review. license: CC-BY-4.0 codeLicense: MIT attribution: gamemechanics.pro contributors catalogKey: catalog/phone-magnetometer --- # Passive physical controllers id: phone-magnetometer--family-07 type: mechanic key: mechanic/phone-magnetometer--family-07 lang: en status: active url: https://gamemechanics.pro/en/knowledge/mechanic/phone-magnetometer--family-07/ A passive button or lever changes the phone sensor’s magnetic field. MagPie is a research prototype for customizable mechanical input. ## At a glance ![MagPie: magnetic buttons and a proposed gamepad scenario](https://gamemechanics.pro/images/mechanics/sensor-magpie-figure1.webp) [MagPie prototype](https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1) · Figure 1 by Insu Kim, Suhyeon Shin, Jaemin Choi, Junseob Kim, Junhyub Lee, Sangeun Oh, Eunji Park and Hyosu Kim. CC BY-NC 4.0: https://creativecommons.org/licenses/by-nc/4.0/ . Cropped from PDF page 1 to the figure and converted to WebP. Figure includes third-party application imagery; Stardew Valley graphics © ConcernedApe. Excluded from portal MIT and CC BY 4.0. 1. Moving the mechanical module changes its magnetic signature - Test magnetic interference and combinations of simultaneous inputs. - [MagPie prototype](https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1) ## How it works Magnetic props turn the physical movement of a knob, slider, or other mechanism into a phone signal. ## Variants ### Variants and applications - Mechanical button. Action: Press a button that moves a magnet or part in a known field. Application: Passive gamepad, trigger, button on the back of the phone. Limitations: Select the position relative to the real sensor and provide for return. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. - Linear slider. Action: Move the magnet along a guide with given ends. Application: Gas, volume, damper position, inventory on a physical scale. Limitations: Requires calibration of the nonlinear dependence of the signal on position. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. - Rotary handle. Action: Rotate the magnet in the housing along a fixed circle or axis. Application: Steering wheel, radio tuning, music controller, safe. Limitations: Not every axis of rotation gives an unambiguous signal; test the full range. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. - Joystick with centering. Action: Deflect the magnetic arm in a limited area; the spring returns it. Applications: Character movement, camera control, analog selection. Limitations: Neutral and deflection areas need training; This is not a replacement for a full-fledged Hall joystick without development. Equipment: Magnetic props with a given geometry. Preparation: Experimental. Type: Input method. - Compression through an elastic part. Action: Compress a spring or elastic element that displaces a magnet. Applications: Grip force, shooting force, musical dynamics. Limitations: Displacement is measured; force can only be assessed through calibrated mechanics. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. - Accessory bend. Action: Bend a plate or arc with a magnet, changing its position. Application: Tensioning a bow, deforming a material, controlling a flexible tool. Limitations: Fix the attachment point and check repeatability after repeated bending. Equipment: Magnetic props with a given geometry. Preparation: Experimental. Type: Input method. - Crank or handle. Action: Rotate a fixed magnet using a cyclic mechanism. Application: Fishing rod reel, meat grinder, wind-up toy, resource generator. Limitations: The rotation speed is limited by the sampling frequency; skipping cycles must be detected. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. - Lever with fixation. Action: Move the mechanism between stable positions. Application: Gearbox, switch, physical mode switch. Limitations: It is necessary to check whether auto-calibration compensates for a long-term constant state. Equipment: Magnetic props with a given geometry. Preparation: Needs setup. Type: Input method. ## Context and limits Author's working classification for designing games and interactions. Options can overlap and combine; the list is not a generally accepted standard or proven exhaustive list. Application examples are conditional unless a specific verifiable observation is indicated nearby. Sources support individual techniques and technical limitations. ## Connected materials ## Sources and provenance Original editorial design catalog consolidated from project discussions on 2026-10-20. Complete discussion item lists and contextual limitations are preserved; linked primary sources support specific techniques, not the entire classification. English translation was prepared with machine assistance and editorial review. - [MagPie prototype](https://ixlab.cau.ac.kr/papers/magpie.pdf#page=1) (id: source-c4196023aaafb085) CC-BY-4.0 · gamemechanics.pro contributors