Actually as the thread progressed we eliminated one stepper for the locking tines when the spring locking plate was introduced to the design.
At the current phase of the design we are down to 1 stepper, 3 or 4 solenoids and a mechanical lever assembly for refresh.
One thing that nags me about the cam design is whether or not it is slower or faster than the solenoid design. Furthermore, using a stepper or servo to drive the cam would require periodic recalibrations (perhaps as many as one per column) to ensure the cam is firing on the correct setting every time. All of this takes time and creates additional noise, further slowing down each output line.
Also I seriously doubt if it would be any, if at all, quieter than the solenoid design with all that mechanical manipulation for each column.
The amount of power required, if at all less, would be negligible with either design I'd think.
Lastly, dot matrix printheads have been around for three decades now and the technology for building a 3x1 or 4x1 solenoid printhead is pretty much cut and dried. In this application the job is even easier since the printhead of the Braille terminal would actually be built on a slightly larger scale than your average pica type character matrix.
All this, particularly the constant recalibration of the cam servo to maintain alignment makes your idea simply less attractive and more costly to implement than my simple dot matrix inspired design.
Sorry, but then again I have opened the floor to innovation on this project and released the material to public domain for anyone to pursue as they will. If you are sold on your cam idea then more power to you in building it, though to me it seems more complex requiring more complicated software to implement than my simple dot matrix design.
Anyone out there who is following this thread is permitted to use my original design in any way they see fit in order to design and build prototypes as well as working production models, hopefully with minimal red tape or delay.
So if you can sell a manufacturer on your cam idea then more power to you brother.
Just as long as street price can be kept below $150 or the price of a medium grade Android tablet.
Gary