The top diagram illustrates the location of the sensors on the robot claw. The X1 sensor is located on the back of the robot claw. It is designed to check whether the robot claw is fully open or not. The X2 sensor is located within the claws, attached to the plastic case that encloses the pivot joint of the two claws. It determines whether an object has been placed within the claws grasp. The third sensor, X3, is located on the tip of the robot claw. It checks for pressure.

The bottom diagram illustrates how the switches are connected to the PLD inputs. In order to prevent excess charge from accumulating inside the PLD, and possibly damaging the internals of it, we placed "pull-up" resistors on the inputs. Thus, if their is a high on an input, it will appear on the PLD input. If there is a low, the pull-up resistor will effectively connect the PLD pin to ground.

At the present time, all of our pull-up resistors are 1k ohm. Although not shown in the diagram, all inputs have a common ground.

To install the switches, we used a plastic material that, when heated to the boiling point of water (100 degrees Celsius), will become soft and pliable. We placed it on the claws and sandwiched the switches into it. If we ever decide to remove the switches, we can heat the plastic back up and pop the switches right off!