Malte Weiß
HCI Research · Software Development

Madgets (2009-2010)

Madgets are actuated controls that can be moved by both the user and the software.

Madgets is the successor of the SLAP Widgets project. SLAP Widgets are flexible, general-purpose for interactive tabletops. However, since they are passive, the communication between user and table is unidirectional. If a control is placed on the surface, the software cannot change its physical state. This can easily lead to inconsistency, e.g., if two remote user share physical widgets. Madgets, magnetic widgets, solves this issue.

The project is based on an interactive tabletop with an embedded array of electromagnets. Our software can control the strength and polarization of every individual electromagnet. Madgets are designed like SLAP Widgets but contain additional permanent magnets. The array of electromagnets beneath the touch-sensitive surface employs the electromagnetic fields to attract or repel these permanent magnets. Thereby, these physical controls can be arbitrarily moved and configured via software. The position of objects on the surface is sensed via fiber-optical tracking. Fiber optical cables are placed next and inside electromagnets and allow a camera inside the table see past the opaque electromagnets.

Madgets increases the design space of physical tabletop objects:


System photos
Widget photos
System architecture


Context This project is part of my PhD.
  • Hardware infrastructure: Interactive tabletop with embedded array of electromagnets and fiber optical tracking mechanism. Custom-made circuit boards and mbed controller trigger actuation process. UI rendering via LCD panel with backlighting via electroluminescence foil.
  • Tangibles: Custom-made by laser-cutting acrylic, attached paper-based markers for tracking, permanent magnets enable electromagnetic actuation
  • Programming languages: Objective-C, C++ (Mac OS X), C++ (mbed microcontroller)
  • Used frameworks: OpenGL, MultiTouchFramework, SLAP Framework, Coin-or linear programming library
  • Malte Weiss
  • Florian Schwarz
  • Simon Jakubowski
  • Jan Borchers

Further Information

Details You find a detailed description of Madgets in my PhD thesis in chapters 4 and 5 (pdf, 7.5 MB)
Links Official project website
Related project SLAP Widgets

Related publications

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