Efficient communication through one or two buttons

David MacKay, Chris Ball, and Mick Donegan.

We discuss how the arithmetic-coding-based communication system, Dasher, could be driven by discrete button presses. We describe several prototypes and predict the information rates of these interfaces.

postscript (Cambridge UK).

postscript (Canada mirror).

pdf (Cambridge UK).

pdf (Canada mirror).

Associated website with presentation slides

Clarification of the single-button channel model.

To estimate the capacity of a single button, we use the following simple model. We assume that the shortest time between two clicks is D and that the precision of click timing, after that time, corresponds to time-intervals of duration g.
Thus the capacity is the same as the capacity of a channel with two symbols, "red" and "blue", which take durations D and g respectively.

How to cite

 title={Efficient  communication with one or two buttons},
 author={David J. C. MacKay and Chris J. Ball and Mick Donegan},
 booktitle={Maximum Entropy and Bayesian Methods},
 editor={Rainer Fischer and Roland Preuss and Udo von Toussaint},
 publisher={American Institute of Physics},
 address={Melville, New York},
 series={AIP Conference Proceedings},
This webpage: http://www.inference.phy.cam.ac.uk/mackay/abstracts/dasherButtons.html. See also this technical report.

All postscript files are compressed with gzip - see this page for advice about gzip, if needed.

related publications.
David MacKay's: home page, publications. bibtex file.
Canadian mirrors: home page, publications. bibtex file.