Designers: Ann Hundley and Stephen Wu
Client Coordinators: Juli Trautman, SLP, CCC, Duke University Medical Center
Supervising Professors: Kevin Caves and Richard Goldberg
To people with limited mobility, Morse code is an attractive alternative for computer access because it involves only two keys, dash and dot, as opposed to the more complex traditional keyboard. We designed a device to help ease the transition from more traditional means of interfacing with a computer to Morse code. The Morse Code Trainer is portable, provides audio and visual feedback, is accessible to a wide variety of clients, and incorporates variable timing to facilitate the learning process.
How this project helped
The client coordinator commented, “The Morse Code trainer will allow my clients without the physical access skills for computer use, to investigate Morse code as a computer access option. Commonly people have a misconception that Morse code is overly complicated and therefore they are reluctant to pursue this option, despite its advantages over switch scanning (e.g. increase in typing rate, reducing cognitive load, etc). By allowing my clients to take the trainer home and practice this technique, they will be able to make a more educated decision, and hopefully understand Morse code’s potential to allow for efficient and effective computer access for people without adequate hand control.”
The Morse Code Trainer (Figure 1) uses a 16F876 PIC microcontroller (Microchip Inc., Chandler AZ), programmed in C, to interpret user input. Two 1/8” mono jacks allow the use of any commercial switch for entering dots and dashes. Pressure switch jacks are also provided for sip and puff input.
The Morse code trainer includes features to make it accessible to clients with a variety of disabilities. For visual accessibility, a high contrast LCD shows the character entered. This LCD has an always-on yellow backlight, and blue background. It also has a large character mode for users with visual impairments. A speaker generates tones of different frequencies to indicate a dot or a dash. A headphone jack the device to be used in a room where other noises might be distracting. Variable controls are provided for end-of-character time and repeat time.
The device is powered by AA batteries, and lightweight for portability. Though every function that may be entered into a computer (including mouse movements) can be encoded in Morse Code, we have implemented only the codes for the alphabet, numbers, enter, space, and period for simplicity.
The cost of parts for the Morse Code Trainer was approximately $225.