4 Sept 2019

First design commitment based off of the 3 individual sub prototypes for each finger. The design brings together the each section into a single shell to make efficient use of space for an extremely compact design. 

Reliability of the hand fares a lot better than the other hands that were designed quickly. Certain parts in this design are designed to be replaceable, such as some of the motor components and finger modules with detachable cords. The replaceable finger modules also allows for easy change of fingers to suit different requirements, such as when holding a pencil for long periods or for fix/sprung fingers for user preference/requirement. 

The performance of the hand works fairly well with the motors used. The motors provide a good amount of torque, and is able hold onto items with a firm grip. The fingers do still require some form of gripping material so the smooth plastic fingers drastically reduces its capabilities in holding items. 

The hand still maintains a fairly easy to print and assemble design whilst being low cost. The overall materials cost is around $40, which makes it fairly affordable for anyone to create, however, the most difficult part to source for this design is the main PCB which handles the motors. Whilst there are some cheap PCB fabrication services online, the main issue comes with the assembly of the PCB which really puts up the price if only doing a one off. It's not an issue for some who's experienced in soldering small ICs to assemble PCBs, but most won't be able to.  For now, I would only recommend those who have experience in soldering to attempt the design if they're interested.

[Additional documentation to be added]

Features:
- Small size
- 4 motor design
- Reasonably good closing strength (firm grip when shaking hands)
- Replaceable/swap-able motor parts and finger modules
- Sprung tips
- Low cost at around $40 in materials (not including batteries)
- Light weight at less than 200g (not including batteries)

Further work:
- Improve ease of assembly
- Add method of wrist attachment
- Additional finger modules
- General design improvements for hand