One touch sensor to control two servo motor sweeping motions is fine, but having an additional touch plate provides an efficient human-machine interface to control robots or industrial machines. As a design challenge, create a buttonless servo motor controller where two touch plates (capacitor sensors) can be used independently to sweep the servo motor clockwise or counterclockwise. Build a second capacitor sensor using the block diagram shown here as your reference assembly diagram:

Wire another 555 timer monostable circuit onto the breadboard using the wiring diagram shown in Building a Capacitive Touch controller section of this chapter for reference. Also, modify the original code shown earlier where two LEDs provide visual direction of the servo motor when touching either CCW or CW touch sensors.

For convenience, mount each capacitor sensor on an appropriate-sized piece of wood, foam core, or cardboard, as shown in the reference assembly diagram. As...