Fall 2015 RoSco Waterproofing Servo Experiment

By: Will McKinney (Project Manager/Electronics and Control)

Experiment 1: Waterproofing Servos

The rover will be tested on December 16, 2015 in an outdoor environment. This year is an El Nino year which leaves us with a very high chance of rain on the day of test. There are three key components on our rover that need to be able to work in these conditions which are the motors, the PCB and the servos.

We will waterproof the motors by enclosing them in the brackets on the sides of the chassis. The Arduino and PCB will be waterproofed by putting them in a waterproof box that we bought from Robotshop.com. Holes will be drilled in the waterproof casing for the wiring to reach the servos and the motors. Lastly, the servos need to be waterproofed. The servos are mounted inside the walls of the chassis and are open to rainfall. The shaft is the most important part to waterproof because that is the main part of the servo that is out in the open. For this, we need to be creative because we cannot just stick it in a box. Listed below are the steps we took to waterproof our servos.

 

Materials:

  • Plastidip
  • Marine Grease
  • Small Screwdriver
  • Servo

 

Procedure:

  1. Unscrew the small screws at the bottom of the servo in order to open up the servo. This allows the top portion of the servo to be taken off.
  2. Apply a generous amount of marine grease around the shaft of the servo. This step ensures that no water will get through the opening in the shaft because marine grease is highly water resistant. After this is done, put the servo back together.

    Waterproofing marine grease

Figure 1: Marine grease is applied to the shaft of the servo

  1. Spray Plastidip around the outside of the servo. This is done best while the servo is hanging because you can get all sides of the servo. Make sure to seal up any openings including the base of the wires.

Plastidip Servos

Figure 2: The first coat of Plastidip is applied. This shows why multiple coats are needed.

2. Hang the servos until they dry. This will typically take 1-2 hours. Multiple coats of Plastidip will be needed for all of the openings.

 

Results:

This experiment was successful. The servos were able to be waterproofed with these four easy steps. The waterproofing was tested by dipping the servos in water for 30 seconds and then testing them to see if they still run. We also dipped them in water while they were running to see if they ran under water. They passed both of these tests.