Hippo - a Small Hovercraft

Hippo is a small skid-craft that propels itself forward with a propeller and turns by rotating the motor to the left or right. It uses two ultrasonic sensors to sense its distance from the right and left sides, and if one of them is smaller and within a particular tolerance, then it will use a servo to turn the motor with the propeller to move the craft in the other direction. The servo controls the motor by rotating the motor assembly on top of it. The whole mechanical design is on a smooth foam platform that slides on the ground.

Ultrasonic Sensor

Piezo Buzzer

5" Propeller

Foam Poster Board

Painter's Tape

Arduino Uno

9V Battery x2

9V Battery Leads

Push Button

Slide Switch

Positional Servo

DC Motor

Bread Board

100K Ohm Resistor

100 Ohm Resistor

Cut a flat sheet of poster board into the shape shown in the image above.

Assemble the circuit diagrams above.

• Take the circuit and hot glue or tape the Arduino and breadboard on top of one another in the center of the piece of foam board, leaving room for the servo in the back and the batteries in the front

• Place two 9V batteries towards the front of the craft (in the circular region)

• Place the servo on the back of the base, and support it with small foam pieces that are hot glued or taped to the base

• The base should now look like the image above

• Attach the dual-pronged servo arm to the servo with a screw

• Wrap the DC motor in a piece of foam and hot glue or tape the motor enclosure to the servo arm in the servo’s neutral position such that the motor is facing directly backward

• Wrap the shaft of the motor in tape until its diameter is slightly larger than the shaft size of the propeller

• Place the propeller over the motor shaft covered in tape

Upload the attached code to the Arduino. Then, connect each battery clip to the batteries in the front of the craft. Ensure that the Arduino is properly sensing by waving your hand in front of the ultrasonic sensors and seeing the motor rotate left and right. Then, flip the slide switch to turn on the motor. The craft will now propel itself forward and steer away from lateral obstacles. At any time, you can press the button on the breadboard to play a song.