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• Devices Supportive of Research
  • Home
  • Low Battery Alarm
  • Transistorized Auditory Gimmick
  • The Fowle Gimmique
  • "Chopper-Comparator"
    or "Null-Type" Readout System
  • Tactor
  • The Alden Non-Linear VCO
  • RERC
  • Smith-Kettlewell

 

This device of Tom Fowle's design is used for making Braille dials. It contains an opto-isolator chopper which compares the position of the dial blank with that of a Braille-calibrated 10-turn precision pot; this 10-turn unit is fitted with its own 20-division Braille Scale. (See SKTF, Vol. 5, No. 1, Winter 1984)

Beyond making dials for electrical instruments, it can be used to make tactile faceplates for timers, mechanical gauges, protractor-type devices (an accessible medical training program in Minnesota has one of the dial makers), postal scales, etc.