BS in General Engineering
Biomedical and General Engineering Department
This project details the design development of an alternative computer input system that allows a person with quadriplegia to move a computer's cursor and activate left and right click button inputs. After researching and analyzing possible solutions, an end design was chosen that most appropriately satisfied all user requirements and engineering specifications. This final design employs a head mounted Inertial Measurement Unit (IMU) with 9 DoF (Degrees of Freedom) to track head movements and correlate these motions to computer cursor movements. A Sip-Puff Transducer monitors and interprets a user's application of negative and positive air pressure differentials to a vinyl tube as analog voltages, which are then interpreted over time to trigger left and right click events. An Arduino Due microcontroller is used to interpret and process these inputs and send mouse commands to the user's computer via a USB connection. In addition to the sensing hardware, there are two indicator LEDs which display the state of the left and right mouse buttons. There are also two adjustment potentiometers, which can be turned to adjust the sensitivity of the mouse tracking and the sip-puff click sensing window.
This system improves upon other alternative computer interfaces by allowing the user to more easily perform complex and non-linear tasks such as file organization and digital painting/drawing. Two accelerometers were initially incorporated into the design to be strapped to the upper arms of the user, and upward and downward accelerations caused by the raising and lowering of each shoulder would have corresponded to the activation of the Control and Shift keys. However, due to issues with program timing and computational complexity, these parts of our design that operated the control and shift keys were abandoned.