I have made a webcam based blink system that allows a user to blink a message. Actually, the system only requires that one can effect two gazes, a regular gaze and a ‘select’ gaze. A helper will use the keyboard to register these two gazes at the beginning. I use template matching to find out if the eye has blinked or made the ‘select’ gaze.
How to use the system
See https://youtu.be/1–6nZVQz3c
Press 1 to start or reset, then press 2 when the gaze is steady (‘regular’ gaze). Press 3 to register the ‘select’ or ‘yes’ gaze. Press 4 to register the ‘no’ gaze (not used currently).
Press 5 to go into action!
The system reads out the ‘menus’ one at a time. There are 5 menus, with 1 to 4 corresponding to 4 rows of a keyboard:
- menu 1 – A, B, C, D, E, F
- menu 2 – G, H, I, J, K, L, M
- menu 3 – N, O, P, Q, R, S
- menu 4 – T, U, V, W, X, Y, Z
When a menu is selected, the system reads out each of the letter in turn. A ‘select’ (‘yes’) gaze will pick the letter and add it to the line (in red). When a line fills up, it is automatically hoisted into a buffer (upper section, in green). The user can thus compose multiple lines of text.
Menu 5 provides a number of functions:
- add a ‘space’ character’
- delete a letter, a word, or the line of text
- There is a warning before ‘line’ deletion, with the announcement of ‘erase coming’, which lets the user skip the deletion if he does not select the next item
- read the line of text
- go into Morse entry mode
- pause the program for 3 minutes
- retrieve the last line in the buffer and put it in the current line for editing
- make a bell sound to attract attention
There are several settings that can be set on the keyboard (e.g. to make the scan faster or slower). These are listed on the screen.
The Morse code entry option
In the main mode, the user waits for the selection to come by. This means that a typical word takes just under a minute to blink out. If the user knows Morse code , then he controls the pace of typing and can blink out a word in under 15 seconds (speed is also adjustable using the keyboard).
Ability Spectrum 
[…] The borescope is mounted on a goggle so the camera does not move when the head moves, thus making the design a lot more robust than using web cam (see https://abilityspectrum.wordpress.com/2015/05/18/blink-is-bliss/) […]