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|Target Environment||Locomotion Method|
|Sensors / Input Devices||Actuators / Output Devices|
|GPS||DC motor for propller
servo for rudder
|Control Method||Power Source|
|CPU Type||Operating System|
|Time to build||Cost to build|
|URL for more information|
|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. This explains the meaning of "Roboat" that is the short form for "robot boat". The project was built in order to take part to the contest "Design99", organized by the magazine "Circuit Cellar". For this purpose the project had to be developed using the new micro-controller "M68HC908GP20" produced by Motorola.
The micro-controller 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.
It can also be connected with a PC in order to control "ROBOAT" for testing purpose and for storing the coordinates of new waypoints. A 12 Volts lead battery supplies power to the devices. The electric motor of the propeller is driven by 12 Volts directly, while the other circuits receive 5 Volts power supply through suitable regulators.
The structure of "ROBOAT" is very simple, so that it can be easily modified and adapted, therefore it is basically made of a sheet of polystyrene foam, 4 cm thick, cut in the shape of a boat, and a thin sheet of plastic on top that actually mounts all the devices: battery, electronics, electric motor, propeller, servo and rudder. While sailing, all the device are covered with a case that protects them from water sprinklings.
Due to the small size and to the reduced capacity of the battery, a typical journey of "ROBOAT" is only a few kilometers long and needs to be done on a quiet and delimited area such as a lake. The area chosen for the first test of "ROBOAT" was the lake "Idroscalo", close to Linate airport, 5 kilometers east of Milan, in northern Italy.
The software is written in assembler for the M68HC908GP20 and controls all the functions of "ROBOAT".