build your own underwater rov from scratch

I was lucky to live in a coastal town, and in the summer I often snorkel near the Rock Creek and enjoy fish, starfish and coral.
I used to take some scenes with my camera and after several attempts to shoot marine flora and fauna, I came to the conclusion that shooting underwater was really challenging!
You have to focus on the scene and stabilize your body without doing too much action to make sure the animal is not afraid.
The second question: apnea.
When you are shooting a little octopus walking quietly on the beach, the air is not enough, which is very frustrating!
In most cases, the result is a short and unstable video sequence. . .
That\'s why I decided to build an \"underwater camera holder\" that can go a few meters deep and shoot stable videos as long as the battery allows.
Why not add lights to restore all real colors underwater?
This structure explains how to build a simple and affordable underwater robot. called CROC (
Compact remote control partner)
, It has the following basic features: Keep in mind that this project is a guide to building your own underwater robot, feel free to add/remove/modify anything; )
You can find the complete 3D model here. Have fun !
Hull and framework electronic demo tool si will assume here that you know how to stick two PVC blocks together, find some tutorials or ask someone if you don\'t know, because we will assemble a lot of PVC components!
However, let me explain how to build a PVC structure called a \"tube\" here \"(
After assembling these structures together, the underwater robot can be roughly obtained).
As you can see on the picture, it consists of the following parts (
From one end to the other)
: Access cover, coupling, pipe, coupling and access cover.
Note that the length of the tube depends only on the length of the intermediate pipe.
You can also replace the coupling with a T-coupling so that you end up with something as shown in the figure.
Note that the angle in the T-coupling is about 87 ° to prevent water from stalling in the pipe, so you must orient the two coupling in the same direction.
The main structure of the hull is as follows: first, you must decide the length of the main hull.
Should not be too small (
You probably don\'t have room to put electronics and batteries inside)
Not too high (
You need to add a lot of weight to make the underwater robot sink).
In my case, the length of 310mm is enough, equivalent to twice the length of the 140mm diameter coupling. 1.
Supervisor of construction (see above)
310mm long, 140mm in diameter. 2.
Two advanced tubes are built with T-joints.
Vertical sections must be aligned! 3.
Glue a 40mm long x 50mm diameter pipe to each vertical end of the superior tube.
These will connect the superior tube with the main tube. 4.
Now put the superior tube on the supervisor and mark the location of the connection.
Let the angle between the two superior tubes be around 90 °. 5.
Drill the main hull in the marked position.
Be careful, drill PVC so that the pipe is perfectly inserted into the hole (
It is even better to make a hole that is slightly tighter than the diameter of the blocked pipe). 6.
Stick two superior tubes to the supervisor.
PVC glue is used inside and outside to ensure the connection is waterproof. 7.
Now check if everything is waterproof: screw 6 covers until it is tight, dip the hull into the basin and check if there are bubbles escaping from the basin.
In my case, I found 4 \"holes\" and I made it completely waterproof by adding more PVC glue to it.
The main structure of the hull is over!
Now let\'s prepare quality tubes for future fixtures and wirings. 8.
Drill a 32mm hole in the center of two caps with a diameter of 50mm.
Stick the 20mm long x 32mm diameter tube inside and let it stick out about 15mm outside. 9.
Take the other two caps with a diameter of 50mm and remove the central part of them (
See below).
Cut two organic glass plates with correct diameter and stick them to the front of the cap with super glue or epoxy glue (
Not PVC glue).
Caution: super glue may produce steam, causing irreparable corrosion to the surface of the plexiglass (
You will see white spots on it). 10.
Once again, screw all the covers to the hull and check the waterproofing (
Let the water outside open the cap! ).
Add PVC glue if necessary.
Now, let\'s add the feet. 11.
Four T-shaped pipes are built using a pipe with a diameter of 40mm.
I built mine and got the T-coupling in contact with each other (minimal length).
Stick a tube at each vertical end.
This time, there is no need to drill the supervisor, which will unnecessarily increase the potential risk of leakage.
Simply stick the foot to the surface of the supervisor: you must engrave the tube that is in contact with the surface of the hull according to the curvature of the tube (
This will strengthen the connection).
In my case, I chose the angle between the feet to be about 70 °.
Note: One thing afterwards, it would be more effective to build 2 feet in exactly the same way as we did to build superior tubes, not 4 feet.
The first reason is that the more components you have, the weaker the global structure.
The second reason is that you can add more weight at 2 feet than 4 feet, which is useful in the stabilization step. 12.
Add a bracket for the camera: stick half of the tube to the front of the hull and screw it into the fixture of the camera (See pictures). 13. (Optional)
T-shaped glue 32mm in diameter.
Coupling at the back of the hull (
The Eternet cable will go through it).
This element is used to connect electronic components together and prevent the battery from sliding while the underwater robot is moving.
The size and shape height of the internal frame depends on the inside diameter and length of the hull and also on the size of the battery. 1.
Build a framework based on numbers.
The external dimensions are 127mm long, 116mm wide and 90mm high. 2.
Insert the battery if needed, block it with paper or carton. 3.
Arduino Mega is slightly wider than the inside width of the frame, so carve the wood so that the board can be attached to the front of the battery (
See pictures). 4.
Connect Arduino board, 3 Double H-
Bridge of 3mm diameter. screws.
A starting hole is required to prevent the frame from cracking.
Stick the switch to the front of the frame. 5.
Connect the terminal blocks to the other side of the frame with glue or cable tie tape.
Since there is no video feedback from the underwater robot (
Is actually a choice)
, When you snore around it, you have to control it and see where you shoot.
After a long period of research, I have not found a way to build an affordable waterproof remote control with a joystick.
The following model is based on the same structure as the superior tube with a diameter of 50mm.
Actually, what I\'m building is made of a pipe with a diameter of 40mm, but it\'s a real challenge to insert two joysticks and all the wires into it, so I suggest using a larger diameter. 1.
A tube with a diameter of 50mm is manufactured with a T joint.
In my case, instead of using a coupling, I stick two tubes vertically to the tube. 2.
Drill a 32mm hole in the center of one of the caps and stick a 20mm long tube inside. 3.
Cut the ends of both fingers into latex gloves and place them on the top of each T-joint (Figure).
That\'s it now!
We can move on to the next step now. Motors1.
To remove the hull of the Hatch pump and install the propeller on the motor, follow this link.
As you can see on the picture, I have to add an extension to the axis. 2.
Connect the motor to the hull with cable ties, glue and/or ropes.
My setup is not very beautiful but works. 3.
Pass the wire on the motor through the pipe stuck to an access cover, and then through the first T-joint. 4.
Connect the wire to the terminal. 5.
Fill the pipe of the cap with epoxy glue.
When dry, screw the lid onto the superior tube. Lamps1.
Weld 20 cm long wires on each pin of the LED light. 2.
Insert the light into the superior tube, right behind the plexiglass cap and pass the wire through the T-joint. Remote Control 1.
Connect or screw the two joysticks to a stick that fits the size of the remote control. 2.
Cut off one end of the 50m Ethernet cable and pass it through the pipe of the access cover.
Let it stretch out a few centimeters. 3.
Fill the pipe with epoxy glue. 4.
Connect the wire of the cable to the joystick and insert the joystick into the remote control.
You can add foam under the joystick and have them pass through the T-joint.
Note: note the correspondence between the output of the joystick and the wires they connect. 5.
Screw the cap and check the water.
Note: putting the joystick in the water will not destroy them, but will cause a short circuit
If the circuit is inserted into the Arduino board, it is the circuit.
In the first test of the swimming pool soak, I encountered this situation: the remote control leaked, the random command was sent to the underwater robot, and it got stuck in a few minutes. 6.
Pull the other end of the Ethernet cable by a T-joint glued to the hull, and then pass through the pipe of the last Superior Tube.
Be sure to get the line to the front shell (add extra 15cm). 7.
Fill the pipe with epoxy glue and screw the cover when everything is dry. 8.
Check again if the hull remains waterproof.
Arduino board, Double H
Bridges, regulators, etc.
The picture above gives a complete schematic diagram. 1.
Connect left-
Moving the motor to the lefthand dual H-
Bridge, do the same for the righthand motors. 2.
Weld the lamp cable to the Molex 4 pin male connector.
Connect the mother Molex connector to the remaining dual H-bridge. 3.
Connect the switch between the battery and other devices. 4. (Optional)
Add a regulator between the switch and the electronic device. 5.
Remove the female/female RJ45 connector and welding cable to its pin.
Connect the cable to the Arduino board and plug the Ethernet cable into the coupler. 6.
Weld the female Banana plug to the anode and cathode of the battery.
Weld 10 cm wires to the plug and attach them to the electronic device. Remarks: 1.
Download ArduinoCROC. ino\". 2.
Adjust the code according to your settings. 3.
Upload the program to the Arduino board.
Note: consider the Arduino code as the basis of the project.
Improve features and add features at any time!
If you are immersed in your underwater robot at this stage of the project, you will observe an obvious pitch imbalance (On the left-right axis)
: The main reason is the location of the battery.
In addition, depending on the mass and total volume, the underwater robot may sink or float.
This is where the feet enter the picture.
Since they are completely waterproof, you can fill them with heavy objects, or instead, let them empty to correct the direction of the underwater robot.
To add weight, you can use sand, gravel, and even metal bars.
In the latter case, make sure they don\'t move with the acceleration or movement of the remote-controlled submersible, as it will change the load redistribution during immersion, which can be dramatic for navigation
You can also add an additional air traffic control to the back of the hull to compensate for the battery weight (
That\'s what I did)
Or inside the hull, add weight around the inner frame.
ROV is balanced when the following two conditions are met: Note: It\'s time for the captain to ride a crocodile!
This is a video of the first navigation in a 3-meter-deep swimming pool.