Existing devices for communicating information to computers are
either bulky, slow, or unreliable. Dasher is a data entry interface
incorporating language modelling and driven by continuous
two-dimensional gestures, e.g. a mouse, a stylus, or eye-tracker.
Tests have shown that, after an hour of practice, novice users reach
a writing speed of about 20 words per minute while taking
dictation. Experienced users achieve writing speeds of about 34 words per
minute, compared with typical ten-finger keyboard typing of 40-60
words per minute.
Although the interface is slower than a conventional keyboard, it is
simple to use, and could be used on personal data assistants and
by motion-impaired computer users. Dasher can readily be used to
enter text from any alphabet.
Desktop Dasher v2
Desktop Dasher v1
JDasher - a Japapese version of Dasher
Movies of Dasher in use
Dasher running on an Handheld
Dasher with an eye-tracker
Dasher running on a PC
Should be viewable with any video player - Media Player (Windows), xanim (X11).
Techsmith TSCC codec
Compesses Dasher animations really well - I think its lossless too.
If you're running Windows, you might need the Techsmith
TSCC codec for Windows.
Apparently, mplayer for Linux will play these animations too.
Here is quite an old animated gif showing someone writing `hello_how_are_you'.
We have Dasher running on a Compaq iPAQ
H3630 handheld: pocket.avi (3.9MB)
Download Dasher for Pocket PC.
Here are some screenshots. The language model has been trained on a book.
To make Dasher an integrated input method.
Make use of the built-in dictionary.
Write With Your Eyes
Dasher with an eye-tracker
AVI of Dasher with an eye-tracker: eye.avi (54MB)
We have an eyetracker from
EyeTech Digital Systems. It
consists of two infra-red emitters, and a camera which plugs into the
back of a PC.
The eyetracker works under MS Windows and replaces the mouse pointer
with a users gaze. Below is a photo of me using Dasher to write with
my eye movement. I can write at about 50-100 characters per
minute (10 - 20 wpm). With further development, faster speeds should
More on Eyetracking
See the Eyetracking
Page for more details of our eyetracking system.
PPM language model
A PPM model is used in many text
compression alogirthms. The one implemented here is order 5 and uses
`escape method D'. It can compress most text to a little over 2 bits
per character. A good reference for PPM is Witten Bell Cleary -
In May 2000, we published a paper describing Dasher and the results of
a user trial.
You can download the paper here.
Some of the experimental results are below.
Each Dasher trial was 5 minutes long.
The keyboard experiment was for control purposes. Each trial was 2 minutes.
August 2002, the main download page for Dasher is
Archive of all releases made by me during my PhD.
A summary on the features available in Dasher
|Configure font size
|Japanese character set
|Scandinavian character sets
|Configure zoom-in rate
A note for Japanese users
The latest version of Dasher does not have support for the Japanese
character sets. This is an issue which should be resolved when cygwin
move to Tcl 8.3.
For the time being, please download dasher165.exe.
You will need to have some Japanses fonts installed.
Dasher in The Financial Times
Discuss Dasher on Yahoo Groups
Click to subscribe to dasher-text-entry
List owner: firstname.lastname@example.org
Browse the discussion group.
Site last modified Mon Jun 9 15:01:44 BST 2003