I've been straight at it, thinking about alternatives for the last actuation system after last weeks events. I think ive got a good robust system this time, that actually is simpler than the last one in terms of components and size. Lesser parts to be 3D Printed, and more that can be bought off-the-shelf
Micro Stepper Motor
3x2 Pogo pins
Using retractable pogo pins, that are engaged/disengaged using some sort of linear motion ( servo/ stepper/spring/solenoid for up and down motion) that pass though a pin-selector slider mechanism that allows only some select pins to pass actuated by the micro stepper motor.
note: once an array of these is built, the engaging/disengageing ( up and down) motion of the pogo pins can happen simultaneously( for all braille cells together) with a since actuator.
What do you think?