Bill Buxton's Notes

The Pantograph is a 2 dimensional force-feedback device. That is, it can be used to input 2D information into the computer, but it is also simultaneously a 2D tactile output device, or display. It was developed in 1993 by Vincent Hayward and Christophe Ramstein. The original motivation was to develop an input technology that would provide access to graphical user interfaces for people with visual disabilities.

In addition to the photo of the device that I have, Vincent Hayward has provided some images of other versions of the device which shed some light on how one explores the design space around a particular idea.

I really liked this device because of its innate simplicity – the design just had an elegance that appealed to me. In describing the project, the developers write:

Various versions have been used in the rehabilitation of visually handicapped persons, micro-gravity experiments, etc... The pantograph has one prominent characteristic: the surface which is being touched neither needs to be grasped not does it need to brace a finger (from an ecological view point, people very seldom use styluses or thimbles to explore objects. Using the pantograph resembles exploring surfaces though a small plate, which is closer to normality). Another feature is very high fidelity: irregularities in the frequency response start at 400Hz and it has 3 orders of magnitude of dynamic range. It has negligible friction and very low inertia which give the illusion (when no force signal is applied) of gliding over an icy surface.

In writing to me about it, Vincent Hayward said:

The Pantograph was, and still is, a fun project to work on. A most rewarding aspect is the spontaneous smiles consistently drawn from the occasional users. It's like as if something completely unexpected was happening. It is the case today like it was in 1993. There is an assumption that what we touch must be veridical, and that what we see or hear can be put in the box and can come out it. This is what made me become interested in touch.

The name was taken not so much because of the number of links and joints in the mechanism, but because a similar structure served as a basis for John Isaac Hawkins' "Polygraph", suggesting the idea of duplication. Another aspect that motivated me in pursuing this project for so long is the mechanical simplicity of the device compared to the amazing large number of interesting questions it raises. I think they will not be answered any time soon.

More about this work can be found in

Ramstein, C., & Hayward, V. (1994). The PANTOGRAPH: a large workspace haptic device for a multi-modal human computer interaction. Conference Companion of CHI'94: ACM Conference on Human Factors in Computing Systems, 57-58.

As well as the accompanying article:

Hayward, V. (2001). Survey of Haptic Interface Research at McGill University. Proceedings of the Workshop in Interactive Multimodal Telepresence Systems. TUM, Munich, Germany, 91-98.

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Bill Buxton
April 2011