{"schemaVersion":1,"record":{"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}],"sections":[{"id":"principle","title":"How it works","body":"Magnetic props turn the physical movement of a knob, slider, or other mechanism into a phone signal."},{"id":"variants","title":"Variants","body":"### Variants and applications\n\n<a id=\"family-07-variants\"></a>\n\n- 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. <a id=\"variant-m049\"></a>\n- 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. <a id=\"variant-m050\"></a>\n- 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. <a id=\"variant-m051\"></a>\n- 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. <a id=\"variant-m052\"></a>\n- 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. <a id=\"variant-m053\"></a>\n- 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. <a id=\"variant-m054\"></a>\n- 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. <a id=\"variant-m055\"></a>\n- 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. <a id=\"variant-m056\"></a>"},{"id":"context","title":"Context and limits","body":"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."}],"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"}}