2015-08-26 (W) Wrist Mounted Chording Keyboard

Progress on the wrist mount had been slow for days. Designs were weak and poorly visualized. A friend showed me a wrist-mounted tool holder which made him think of what I was trying to do. Tim, the author of the Robotic 3rd Hand used a pair of four-bar linkages, like I was planning to do, but he did so with one servo and 3D printed parts. Refinements on his project showed a lot of care and attention to detail which will not be copied in this design, not right away. First, a working model will be built to prove the design then changes can me made to make it more comfortable and functional.

Enough background.

Sketches were made of a 3D design which would hold servos and allow for #6 (3.5mm) bolts to be used as cross members. Advantages of the cross-members included the ability to change the distance between servos, less plastic to print, and duplicate pieces could be printed instead of one structure.

Sketches of design for wrist mount

Footprints of small servos were drafted, specifically the SG90 and MG90, which were the same size. These servo footprints can be used to create pockets in models where a servo can fit. Modules are reusable and available in the Downloadable Files below.

OpenSCAD servo footprint module

Downloadable Files:
To do:
  • Modify servos for continuous rotation.
  • Wrist mount
    • Design
    • Model
    •  Build
    • Test
    • Refine
    • Repeat
    • Activation switch
    • Route wires
  • Write instructions
    • Schematic

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2

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2015-08-25 02 (Tu)