Special Needs and Accessibility
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.
Input Methods
Dasher can be driven using any two-dimensional pointing device:
Standard Pointing Devices
- Mouse
- Trackpad
- Touchscreen
- Rollerball
- Joystick
Hands-Free Options
- Head mouse - controls cursor via head movement
- Eye-tracker - gaze-based control for completely hands-free writing
- Foot mouse - foot-controlled cursor
Eye-Tracking Performance
With an eye-tracker, Dasher provides a completely hands-free writing system. After one hour’s practice, some users are able to write at more than 20 words per minute. Experienced users reach 30 words per minute.
Compared to an eye-tracker + on-screen keyboard, Dasher is:
- Faster - More efficient text entry
- More accurate - Better error correction built in
- More fun - Natural, fluid interaction
For a movie demonstrating Dasher with an eye-tracker, see our demonstrations page.
Frequently Asked Questions
I am paralyzed from the shoulders down. What do I need to make Dasher work for me?
If you have a PC (Linux or Windows) and can use a head-mouse:
Simply download the latest version of Dasher, and you should be able to write with Dasher. You may use a mouth-stick that controls the mouse coordinates as well.
If standard mice and head-mice are not an option:
You'll need an eye-tracker that can take over control of the mouse. Several systems are available (see recommendations below).
Hardware Recommendations
Head Mice
Smart-Nav Head Mouse (Highly Recommended)
Manufacturer: NaturalPoint (formerly sold as TrackIR)
Price: About $150-$300
Uses one reflective dot stuck to your head and a small camera attached to your Windows machine. We recommend this device because it is cheap, easy to set up, and versatile.
Tip: You can stick the dot on your finger or toe to make a finger-mouse or toe-mouse. Best results are achieved by putting the dot on an extension to amplify body motion, or on the tip of a baseball hat.
HeadMouse Extreme (Origin Instruments)
Price: About $1000
Works instantly as a USB mouse, requiring no software at all. Works on Linux and Mac too. A very good product, though expensive.
Eye-Trackers
Quickglance (Eyetech)
Price: About $3000
Very good value. Recommended settings: Update Rate 30, Smoothing Factor 1 or 2.
Tobii MyTobii
Price: About $25,000
The king of gaze-trackers - tracks both eyes and is robust to enormous head motions. Very impressive but expensive.
Eyegaze (LC Technologies)
A high-quality tracker, very easy to use. Works with Dasher.
Eye Response Erica
High-quality tracker with sensible patented features such as automated zoom when you dwell-click. Eye Response ships their product with Dasher included.
Additional Resources
ACE Centre (UK)
Centre of information, support, and training for parents and professionals in the use of technology for young people with communication difficulties.
AbilityNet
11 centres around the UK who can help disabled people use whatever technology is appropriate for them, including Dasher.
Skipper Project
Free software for Linux machines including advice about making custom hardware for on-screen mouse control.
Speech Synthesis Integration
Dasher can be integrated with speech synthesis systems for users who need both text entry and speech output. Integration is available for both Linux and Windows systems.
Get Started
Ready to try Dasher? Download and install or watch demonstrations to see Dasher in action.