Sensory stimulation substitution system for blind persons - has stimulation generator with centre tapping of transformer connected to battery terminal via switch

摘要

The sensory stimulation substitution system produces electrical impulses transmitted via electrodes to the skin to cause a sensation. The strength of the latter is affected by modulation of the amplitude, pulse duration, interval and/or change-over frequency of the current by light sensors. The generator is supplied by a battery (1), and the stepped-up voltage necessary for stimulation is obtained by connecting the centre tapping (4) of the transformer via a switch (2) with one battery terminal. The outer terminals (5, 6) of the transformer are connected via a change-over switch (3) to the other pole, switch operation being effected automatically by change of direction of the transformer secondary (7) so that no coupling condensers separate from the electrodes are necessary.