Dasher

What is Dasher

(Information source: Inference Group)

Dasher is highly appropriate for computer users who are unable to use a two-handed keyboard. One-handed users and users with no hands love Dasher. The only ability that is required is sight. It can be driven using a mouse, a trackpad, a touchscreen, a rollerball, or a joystick - any two-dimensional pointing device that can take over the role of a mouse. A foot mouse and a head mouse are additional options. It can also be driven using an eyetracker, giving a completely-hands-free writing system. After one hour's practice, some users are able to write at more than 20 words per minute using Dasher with an eyetracker. Experienced users reach 30 words per minute. We got these results with the Quick Glance gazetracker from EyeTech Digital Systems.

Frequent Questions


I am paralyzed from the shoulders down. What do I need to make Dasher work for me? Do you have a PC? (Linux or Windows) Can you use a head-mouse? Or any other sort of mouse? Perhaps a mouth-stick that controls the mouse coordinates? If so, simply download the latest version of Dasher, and you should be able to write with Dasher. If standard mice and head-mice are not an option, then you'll need an eyetracker that can take over control of the mouse. We used a system from Eyetech called Quickglance. See below for links to other gaze-trackers.

Hardware options

Here are some links giving information about non-standard mouse devices.
  • Head mouse, Highly recommended: Smart-Nav Head mouse from NaturalPoint (formerly sold as the TrackIR; don't buy a TrackIR now, however, as the current (2005) TrackIR is now specialised for gaming)
  • Uses one reflective dot stuck to your head and a small camera attached to your windows machine. (No linux version is currently available, but if NaturalPoint hear there is demand, I think they might respond!)
    You can stick the dot on your finger or toe to make a finger-mouse or toe-mouse. We got best results by putting the dot on an extension so as to get accurate amplification of the body motion. Equivalently, put the reflective dot on the tip of a baseball hat. SETTINGS - for our first TrackIR, bought about 2002: We put Natural Point's "speed" control at its maximum (but not 2x) and its "smooth" control towards "-". For the smartnav3, we put the smoothing control to its smallest value (slider to the left), and the speed controls (for x and y amplification) in the middle; I wasn't sure whether I preferred Relative or Absolute mode. Further advice from users.
    Other headmice: We very highly recommend the Origin Instruments HeadMouse Extreme , which feels a lot like a Navpoint smartnav to use, but has the advantage that it works instantly as a USB mouse, requiring no software at all. So it works on linux and mac too!
  • Skipper (http://home.freeuk.net/skipperproject) includes advice about making your own custom hardware to enable control of your on-screen mouse and other other aspects of your computer. Free software is included for linux machines.
  • Head-mouse From MouseVision Inc: VisualMouse (VM) software - widely used by disabled people, can be downloaded from www.mousevision.com free of charge. VM is a pointing device using a webcam that recognizes head motion (with no gear on the head). It works with Windows 98/ME/2000. [23/8/02.]
  • A free headmouse. It runs under Windows.
  • GyroMouse - Free space mouse - good for people with limited reach - and could probably be used as a head mouse or foot mouse.
  • Carpal tunnel-friendly mouse: One Dasher-user recommends the hand-held IBM GlidePoint mouse.
  • Eyetrackers: Eyetech - we used their Quickglance eyetracker, which costs about $3000. Very good value. We used the following settings: Setup->More Options->Update Rate 30, Smoothing Factor 1 or 2. (in contrast to the defaults which are 10, 7). Further info about the system is provided here.
  • Eyetrackers: Eyegaze (LC) A high-quality tracker, and very easy to use. Works with Dasher, Though LC technologies have not pushed this opportunity (as of Oct 2005).
  • Eye response Erica A high-quality tracker, and easy to use. Comes with sensible patented features such as an automated zoom whenever you dwell-click on a small piece of the windows display. Works with Dasher, and Eye response ship their product with Dasher. They are actively working (as of Octo 2005) on making their gaze tracking software change its behaviour when you are using Dasher (very responsive behaviour is good for Dasher). ($8000 for a complete system based on a tablet PC)
  • Tobii's MyTobii -- the king of gaze-trackers - this one tracks both eyes and is robust to enormous head motions. Very impressive. About $25,000.
  • Foot-control: Vik writes:
    "I thought you might like to know that I have been running the Linux version of Dasher on the Sony Playstation 2. I used the Sony "Dance Mat" controller to control Dasher with my feet. This is a relatively low-cost platform with a variety of controllers available, some of which may suit certain disabilites."
  • Trackers and software from Madentec
(Information source: Inference Group)

Demonstration




Writing sentences with a red ball using Dasher and RoboRealm

Dasher: information-efficient text entry


Dasher on an iPaq

So schreibt man mit Dasher




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