--- title: Magnetic Lock Opens By Magic | daily.dev description: Stephen Cass has a project where a lock opens only when a magnetic stylus draws a specific gesture across it. Inside sits a Teensy reading an 8x8 grid of 64... canonical: https://daily.dev/posts/magnetic-lock-opens-by-magic-tb1ibnzqb twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Magnetic Lock Opens By Magic | daily.dev og:description: Stephen Cass has a project where a lock opens only when a magnetic stylus draws a specific gesture across it. Inside sits a Teensy reading an 8x8 grid of 64... og:url: https://daily.dev/posts/magnetic-lock-opens-by-magic-tb1ibnzqb og:image: https://api.daily.dev/og/posts/TB1iBnzQB.png og:image:alt: Magnetic Lock Opens By Magic og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Magnetic Lock Opens By Magic **[Hackaday](https://daily.dev/sources/hackaday)** · 2 min read · 0 upvotes · 0 comments ## Summary Stephen Cass has a project where a lock opens only when a magnetic stylus draws a specific gesture across it. Inside sits a Teensy reading an 8x8 grid of 64 Hall-effect sensors developed by Peter Jansen. The system lets you train your own unlock gesture, though the small sensor area makes drawing it reliably tricky. A Celtic knotwork pattern on the box hides the reference point for the gesture, but the lock stays shut forever if the battery dies, short of breaking it open. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How can I build a lock that unlocks with a magnetic gesture instead of a simple magnet? Use an 8x8 grid of 64 Hall-effect sensors, developed by Peter Jansen, read by a Teensy microcontroller to detect a specific trained magnetic gesture drawn with a magnetic stylus. This avoids the flaw of magnet-only locks, which any strong magnet can open. The main drawbacks are the small sensing area, which makes drawing the gesture reliably difficult, and total lock-out if the battery dies. _Tinkerers prototyping sensor-based locks compare hardware approaches and trade-offs like these on daily.dev._ ## Similar posts on daily.dev - [This design software reimagines everyday objects as self-aware devices](https://daily.dev/posts/this-design-software-reimagines-everyday-objects-as-self-aware-devices-b2nqjjlh6) · MIT News · 0 upvotes · 0 comments - [etinaude/Lock-Picking-Robot: Lock picking robot](https://daily.dev/posts/etinaude-lock-picking-robot-lock-picking-robot-k01noktgk) · Hacker News · 0 upvotes · 0 comments - [Making The Most Pick-Proof Lock Yet](https://daily.dev/posts/making-the-most-pick-proof-lock-yet-wcwxenurz) · Hackaday · 0 upvotes · 0 comments - [With a swipe of a magnet, microscopic “magno-bots” perform complex maneuvers](https://daily.dev/posts/with-a-swipe-of-a-magnet-microscopic-magno-bots-perform-complex-maneuvers-jhfub3ikd) · MIT News · 0 upvotes · 0 comments - [Someone made an Arduino-powered NFC scanner that treats physical movies like cartridges](https://daily.dev/posts/someone-made-an-arduino-powered-nfc-scanner-that-treats-physical-movies-like-cartridges-blzsod2hj) · XDA Developers · 0 upvotes · 0 comments --- Tags: [#embedded](https://daily.dev/tags/embedded) [View this post on daily.dev](https://daily.dev/posts/magnetic-lock-opens-by-magic-tb1ibnzqb) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Magnetic Lock Opens By Magic","url":"https://daily.dev/posts/magnetic-lock-opens-by-magic-tb1ibnzqb","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/magnetic-lock-opens-by-magic-tb1ibnzqb"},"datePublished":"2026-10-29T08:16:36.433Z","dateModified":"2026-10-29T08:17:10.778Z","description":"Stephen Cass has a project where a lock opens only when a magnetic stylus draws a specific gesture across it. 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This avoids the flaw of magnet-only locks, which any strong magnet can open. The main drawbacks are the small sensing area, which makes drawing the gesture reliably difficult, and total lock-out if the battery dies. Tinkerers prototyping sensor-based locks compare hardware approaches and trade-offs like these on daily.dev."}}]} ```