A few weeks ago,a close friend of mine(Reynard) challenge me to build a robotic cleaning thing.As answer to his challenge,i built this thing that can clean my pool easily.

In this tutorial ill show you how to make a remote controlled ROPC using cheap homade materials.This project cost around 12-20\$ (depends where you live).This ropc don't have any tether.And can go down to 0,4 meters deep.

This project is inspired by Rui santos(check him out).The goal of this project is to create a fun toy for kids but can also explore our environment.We can also put a lot of sensors in it/on it.

## Step 1: How My Design Work

My design is pretty simple.It basically just use a tank drive principal,they're also known as differential thrust principal.

If you wanna know more about tank drive principal this is the link:https://www.quora.com/How-does-a-military-tank-turn-left-or-right

Theres another law working in this project.I don't know the name(LOL)but ill explain it to you.(it might be newtons third law).

## Step 2: The Formula to Make This ROV Work!

You cannot just make and put the stuffs anywhere you like.Theres a little bit of physics is involved in this project,which includes neutral buoyancy and mass distribution.I'll give you guys links :) .

neutral buoyancy explained: https://en.wikipedia.org/wiki/Neutral_buoyancy

neutral buoyancy formulas: http://www.kentshillphysics.net/fluids/buoyancy-a...

http://physics.tutorcircle.com/fluid-dynamics/buo...

mass distribution explained: https://en.wikipedia.org/wiki/Mass_distribution

mass distribution formula:

A simple way to find neutral buoyancy is by putting the box into the pool,when you push the top gently it will bounce up and down in the pool.If it floats you should give more weight(pebbles).

A simple way to find mass distribution is watching it while its floating(in neutral buoyancy mode),if it tilts forward/left/right/backwards you should give a thing to counter the weight.

example:if the box tilts forward you should put a thing at the back of the box.

if the box tilts right you should put a thing at the left of the box.

## Step 3: Collecting Materials

For my project i decided too make mine as cheap as possible.I use the L293D IC to control the motor.You can use an arduino uno/mega with a dc motor shield as a substitute.

Parts Required
1x Arduino uno

1x Bluetooth Module (for example: HC-05)

1x Smartphone (any Android will work)

1x L293D IC

2x DC motor

Jumper Cables

1x waterproof box

1x go pro(optional;I'm actually using a clone go pro)

1x powerbank(i used the 1200mah one)

2x fishing net(small one)

Tools Required

Soldering tool

Strong glue(UHU preferably)

Dremel or drill

Silicone glue

## Step 4: The Schematic and Design

This is the design.I just basically use my box as a fuselage and use differential thrust to go forward.I decided to use 2 fishing net as a cleaning tool cause its cheap and easy to upgrade

## Step 5: The Code

thx rui santos for the code.Be sure to check him out!!

## Step 6: The Circuit

Rather then making it permanent i choose to make it semipermanent(use breadboard).Just follow the schematic and you'll be fine.I connect mine onto a mini breadboard so i can modify it anytime i want.Attaching is pretty simple(you just need to follow the schematic).But ill show you the bluetooth connection cuz thats where people usually get confused.

from bluetooth to arduino nano

RX goes to TX

TX goes to RX

VCC goes to 5V

GND goes to GND

Also connect the dc motors onto the circuit. Ps:dont connect the battery first :)

## Step 7: Building the Body

In this step i will try to explain how i build my ROV.Bear with with me,its not easy at all.First of all start planning where to put you're arduino,battery,and other components.Watch out the hc 05 module is quite tall,if you're fuselage is too short you should separate the bluetooth module from the breadboard and connect the module too the breadboard using jumper cables.

Then start by cutting the 2 fishing pole handle(leave 2 cm).Then drill 3 holes,2 on each side(for fishing pole).And 1 for the motors(below).

You can look the pics for more detail.I attach a few lego technic bricks too stop the camera.You can attach the brick anyway you like.Watch out for weight distribution as you might make 1 side more heavy then the other

#DO NOT ATTACH THE DC MOTOR FIRST!!

#DO NOT ATTACH ANY COMPONENTS TOO!!

## Step 8: Attaching the Motors =)

You can also try some tamiya motors.It is more costly and takes more current tough.But the speed you'll reach is worth the price.

## Step 9: Final Assembly

Now after doing all that work the final moment has arrived.

Step 1:Glue/attach the breadboard onto the box(with the components attached of course)

Step 2:You should give some foam as a protection

Step 3:Connect the battery

Step 4:If it turns on ,CONGRATULATION

## Step 10: Decorating

I just used an acrylic glue to colour my ROV(its yellow coloured).Give it some decoration such as shark face or patterns and a name.

A few painting tips:-Paint the cover separately from the body.

-Use baby oil so the paint won't get stick onto you're hands.

## Step 11: The Application

The app i use is created by Rui santos using MIT app inventor.The app is called "Blue ard" the 1.0 version.

## Step 12: Some Notes

-You need to remove the RX and TX cables when you’re uploading the sketch to your Arduino(sometimes).

-If you connect the TX from the bluetooth module to the TX of the Arduino it won’t work. Make sure you connect it properly, the TX into RX and the RX into the TX.

-If the HC-05 Bluetooth Module asks for a password, It’s ’1234′ or '0000' .

-Before Testing the “BlueArd” app, test if you’ve made all the connections correctly. How you can do that? Simply enter numbers (‘1’, ‘2’, ‘3’, ‘4’ and ‘5’) into your serial monitor and your DC motors should be working properly.

-Don't forget to waterproof everything.I used silicone glue to cover all holes

## Step 13: DONE!:)

If you have reach this step congrats you just built a working,diving ,floating,stalking ROPC.

I like to show my gratitude to my mate named aaron and reynard .Thx to their help i can finish this project.I hope i can repay them ;) .More pic will be added!

## Step 14: My Fails and Errors

This step is only a fail footage step :)

second fail:motors require 6V!!