Riccardo's first-prize-winning Design 99 project tests the feasibility of an autonomous GPS-guided model. Step aboard for this stem-to-stern review of everything from the details of construction to the software required for its maiden voyage.

Start • Mecahnical Assembly • GPS - Digital Compass • Proportional Servo • Circuit Description • Software • Test Modes • Crossing the Atlantic • Sources

This project aims at testing the feasibility of driving an object using a GPS and a digital compass. In this case, the object is a model boat that can sail autonomously along a course planned in advance.

At the core of the Roboat is the M68HC908GP20 (the quad flat plastic pack version) controller that stores the coordinates of the waypoints to follow and, according to the data received from the GPS and from the digital compass, controls the electric motor for the propeller and the proportional servo for the rudder. Three switches enable the test modes (disabling the control of GPS and/or compass), and a potentiometer allows you to trim the rudder center position.

A MON08 interface allows the connection with the ICS08GP20 board, in order to control the Roboat directly from a PC for testing purpose and when new waypoints need to be stored.

A 12-V lead battery supplies power to the devices. The electric motor of the propeller is driven by 12-V directly, while the other circuits receive a 5-V power supply through a suitable regulator.