Robot Fish (for Cistern Inspection)

In this project, will be described step by step, the process of doing a robot fish. It is not easy for electronics to survive aquatics. This robot has some basic behaviors, for example, when the nose sensor detects a collision, the fish turns in order to avoid the obstacle.

One of the reasons of the project, consist on making a low cost robot using recycled materials. The main materials used were: milk cans, a plastic bottle, kitchen gloves and plasticine.

The list of the used
materials is:

Electonics:

- Arduino Nano

- Bluetooth module HC-06

- Ultra bright LEDs

- Distance sensor (IR emitter and IR receiver)

- Battery pack (4 AA batteries)

- On-off switch

- Three servomotors

Robot components:

- Plastic coffee cup

- Plastic bottle (mayonnaise bottle)

- Latex gloves

- Milk can

- Electrical tape

- Epoxy glue

- Silicon glue

- Plasticine

The propulsion and direction system consist on three servomotors, one for forward, right-left propulsion and two smaller servomotors for immersion control. In order to protect the motors, a cover using latex gloves is placed. For seal the motors and the interior of the robot, a silicon is used.

The three motors are placed in the plastic bottle, which will contain inside all the electronics and power supply for the robot.

In this step, the electronics for the robot is tested and improved. The sensors, the Bluetooth module, the LEDs and the servomotors are tested. When the software, the electronics, the actuators and the sensors integration are properly working together, is time to integrate it into the hardware.

Some tests are performed together with the main body of the robot.

The robot tail was done using the material from the milk can and acrylic. This material is like carton, but water resistant. A light beacon also will be integrated at the end of the tail.

To protect the servomotor from water, the latex gloves were used. During the manufacturing the propulsion system was damaged. A repair procedure was performed in order to fix again the tail.

After all the components are tested, are properly working and the final assembly is performed, the time for some tests in water has come. On this first test, the robot had some technical issues, but were finaly solved

The robot fish is tested in a real environmen: dark, small and hard to reach for a person. The main objective was reached and the robot fish achieved a great performance in water.