An off the shelf Logictech three button mouse, with a serial connector, was selected as the sentic mouse because of its ease of disassembly. Removing the three screws on the underside, the shell separated easily from the logic board. The force resistor, see figure 3-2 was affixed to the index button with silicon sealant, and the MediaPoint (TM) rubber joystick affixed on top of the sensor using the same sealant. Due to the fragility of the plastic sensor, silicon sealant was chosen over many other forms of adhesion including solder, tape, and many kinds of glue. An eight strand ISDN phone cord was soldered to the sensor connector, and secured inside the shell of the mouse. For this experiment only the front and the back quadrants of the resistor are monitored to provide horizontal and vertical data signals. However, the prototype was built to permit future use of all four quadrants in the event that the recording of the side to side motion becomes desirable.
[Figure 3-2: The sensor is a four quadrant
force resistor.]