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Improving the design

A project log for MOLBED Modular Low cost Braille Electronic Display

A project that I started in 2014, aimed to develop a low cost and modular refreshable Braille system

MadaeonMadaeon 08/01/2016 at 15:160 Comments

Now that the single pin and the character have proven to work, I am focusing on the electronic design.

The character PCB has to connect the 6/8 coils with the connector that plugs into the line PCB.

The line PCB will control through H-bridges the coils, and (it's no begin tested) it would be very useful if it can also sense when a pin in pressed down, so the module can be used to "write" too.

In the meanwhile, the quest for the best optimization of the single pin leads to testing of a different design!

In this design the got an even lower part count: every Pin has just 3 3d-printed / injection moulding parts, and two Flexinol wires, and still can offer a bi-stable behaviour and power is needed only to change state. The Flexinol wire (you can find some technical info here) is used as an actuator. Around 10cm of wire is used for the "up" movement and the same amount for the opposite direction. Assuming a 4-5% amount of shrinkage when activated, it should provide 4-5mm of movement that should result in 2-2.5mm travel distance of the pin. The wire is wrapped around the moving part in order to keep the Pin small, with enough wire to get at least 2mm of travel.

Currently I am 3D printing the body and the front/back halves.

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