Project Details

We worked in a team of three to build a boat that followed an ultrasonic source. Two angled ultrasonic transducers received the input signal, and based on whether the left or right input had the higher amplitude, the corresponding fan would blow harder. We soldered the components to the PCB and built all circuits ourselves.

We used proportional control for the fan output and automatic gain control for a controlled output signal amplitude. A bandpass filter improved the signal-to-noise ratio. The filter rectifier circuits convert the AC to stable DC voltages, which are compared in the subtracter. The proportional control loop sets the width of the PWM circuit that drives the fans. The signal is inverted for one of the fans so one is stronger and the boat turns.

• Date: March 2017