Design Ideas December 19, 1996

Program generates Braille dot code

Jose Carlos Cossio, Santander, Spain

  Shyam Sunder Tiwari, IGCAR, Kalpakkam, IndiaThe Basic training program in Listing 1 helps visually handicapped people easily learn Braille dot code with the help of a trainer. The trainer generates six-pin Braille code using six solenoids operating on an LPT1/2 either by directly connecting the low-power solenoids to the data bits of the parallel port or by driving solenoid pins (pull-out type) using an UN2003 power driver (Figure 1). Push-in type solenoids require complemented (0 for 1 and 1 for 0) Braille-code data bits or an extra inverter on the LPT1 port.

  The user directly senses the Braille code using the six solenoid pins. These pins are also useful for punching the coded characters on paper. The trainer doesn't need to know the Braille code; he or she can generate code by simply typing plain English characters for the desired Braille code.

  You can assign the LPT1/2 data bits to the Braille solenoid- pin positions to make visual identification convenient. Table 1 lists the assignments, as does the program that generates the Braille code on the printer port of the PC. If you alter the pin position with respect to the data bits, you need to modify the corresponding stored codes C(1) to C(40) in the program. (DI #1963)

| EDN Access | feedback | subscribe to EDN! |