Post 8 - Concept 2
The mechanism in this concept was based on the string pull system used in other prosthetic hands available at the Enabling the future website.
Because it was a tried and tested system, it was proven to control the finger movement and be easy to assemble. These features meet some of the criteria set out in my design intent statement. Modifications were made to allow for added functions of single and double-clicking the index finger, locking the thumb and small finger in position and flipping the trigger mechanism to function in an upwards wrist bend instead of a downwards action.
The full set of actions were broken into four functions.
For the majority of the remaining time, my focus remained on prototyping and testing the above functions. Then followed by iterating and repeating.
Each function was tested individually before integrating with the next.
The first iteration of concept 2 was a simplified Talon hand with the control strings hanging freely.
Pulling individual strings gave the desired effects of locking the mouse in between the thumb and the little finger, clicking the left button or grasping all fingers at once.
With many iterations, personal testing and modifications concept 2 has successfully been able to meet some of the criteria set.
With a total cost under $20 keeping it at an affordable price for an individual in a developed country. A breakdown of the cost is $15 worth of ABS filament and <$5 for six elastic bands and five screws.
Neutral hand position, cursor control, left clicking and double clicking is possible. The allows the control level to fit into the Basic category of mouse control.