Introduction: PVC Submarine

Picture of PVC Submarine

In this instructable we will be building a submersible. When finished you should have a submersible with motors and electronics to control it. It should be able to go up and down and turn left and right in a pool.

You will need the following:

3x Motors

3x Motor casing

1x Magnet 10’ PVC pipe

4x PVC Elbow connectors 3x

PVC “T” connectors 1x PVC cap

3x 6-pin switch https://goo.gl/wX97XN

1x Ring of plumbers wax

1x Power supply https://goo.gl/9OXCXd

5’ Solder

30’ 8 core wire

3’ 2 core wire

Step 1: Cut the PVC

Take the 10’ of PVC and cut it into the following lengths:

2x 7” PVC section 2x 5” PVC section 4x 2.5” PVC section 1x 2” PVC section

The remaining length can be put aside for if if you mess up, or another project.

Step 2: Assemble the Back

Picture of Assemble the Back

First we will be assembling the back portion of the sub. Take one of the 5” PVC sections and connect two of the elbow connectors to it. When completed it should look like the picture above.

Step 3: Assemble the Front

Picture of Assemble the Front

Next we will assemble the front part of the sub. For this step you will need all four 2.5” PVC sections, the 2” PVC section, two elbow connectors, one “T” connector, and the PVC cap. First put one 2.5” PVC section into each of the horizontal sides of the “T” connector. Then attach one elbow connector to each previously built 2.5” PVC section so that they face away from the third prong of the “T” connector. Take the remaining 2.5” PVC sections and put them in the empty side of the elbow connectors. Put the cap on the 2” PVC section and put it in the open side of the “T” connector. Use the picture above for reference.

Step 4: Assemble the Mid-section

Picture of Assemble the Mid-section

Assemble the mid section. Put both of the 7” PVC sections into one of the horizontal holes on “T” connectors. Then attach both parts using the 5” PVC section via the vertical coles on the “T” connectors as seen in the picture above.

Step 5: Combine the Middle and the Back

Picture of Combine the Middle and the Back

Take the completed middle and back section and connect them together. It should look like the picture above.

Step 6: Combine the Middle and the Front

Picture of Combine the Middle and the Front

Take the main part of the sub and connect the front piece. You may have to adjust how far in each pipe is to make it fit but it should end up looking like the picture above.

Step 7: Prepare the Motors

Picture of Prepare the Motors

Now we will begin assembling the motors. Take the 2 core wire and split it into 3 lengths of 1’ each. Strip the wires so that about 2-3 millimeters of copper is showing on one side of the wire. Solder one wire to each motor, it doesn't matter which color is on each terminal as long as you are consistent on all three.

Step 8: Waterproof the Motors

Picture of Waterproof the Motors

Roll the plumbers wax into 6 balls. Three should be about the diameter of a quarter and the other three should be about the diameter of a nickel. Take one of the quarter-sized balls and put it inside the motor casing. Put the motor in the casing, axle-first, and push the motor through the wax so the the axle pokes through the hole in the casing. Thread the wire on the end of the motor through the hole in the cap of the casing, but don’t seal the casing just yet, and place one of the smaller balls of wax on the end of the motor. Seal the cap on the motor casing and wipe off any excess wax. Repeat two more times so that all three motors are watertight. Finally attach the motor blades to each motor axle using super glue.

Step 9: Attach the Motors

Picture of Attach the Motors

Now we need to attach the motors to the frame of the sub. Take a motor and at least one zip tie. Turn the sub over, the motors will be attached to the bottom of the sub, and lay your motor down horizontally on the left-back corner of the sub with the blades facing straight behind the sub. Try to make the motor flush with the frame of the sub. Wrap a zip tie around the motor and the frame, but make sure you have the zip tie on the right way. Tighten the zip tie enough to make sure the motor will stay in place, but not so tight that the cap of the motor case starts coming off. Repeat the same for the right-back corner of the sub, and if the motors are still loose you can add more zip ties and cut off any excess material from the zip ties.

For the center motor you will need to lay a zip tie against the motor and attach it with two other zip ties near the top and bottom of the motor. Cut off excess material again and wrap the zip tie that’s laying against the motor around the bar across the frame near the motor, make sure the sub is still upside down and the blades are facing upwards. Firmly tighten the zip tie near the center of the bar and cut off excess material.

Step 10: Secure the Motors

Picture of Secure the Motors

Use a roll of electrical tape to help secure the motors even more, you don’t want them moving around while you’re in the water. Start with the corner motors, using one long, continuous piece of tape, attach the end of the tape to the frame and wrap the tape around the motor. Slightly move the tape over every time you complete a rotation around the frame and the motor as to give more support. This should be done enough to secure the motor in place. You should also attempt to seal the cap of the motor casing to prevent any water from leaking in. Be careful around the propellers as to not tape the shaft to the motor casing, doing so would cause unnecessary friction. Finally cut the tape. Repeat this process other corner motor.

For the center motor, start at the frame and move the tape over the motor diagonally. Bring the tape across the bar which the center motor sits on and move the tape straight down. The tape should now be on the side of the motor, opposite to the starting point of the tape. Move the tape diagonally across the motor as to overlap the other part of the tape and move the tape across the back of the bar and straight down to overlap the starting point. The tape should like an “X” across the motor, connected by two vertical lines across the back of the bar. Repeat these steps until the center motor is stable, and make sure the motor is really in the center. Try to make sure the casing won’t leak and the tape doesn’t touch the shaft of the propeller. Finally, cut the tape and make the end flush.

Step 11: Solder the Switches

Picture of Solder the Switches

Next we need to solder the switches. Take the 8 core wire and cut three 1’ sections. Strip the wire casing back about 3-4 inches and then strip each core wire back ¼”. Bend back two of the core wires, you only need six of them. Take the exposed metal on the end of the core wires and bend them in the shape of small hook. And solder them onto the switches like the picture above.

Step 12: Solder Switches

Picture of Solder Switches

Solder together the oppsite corner wires of the switches. If you look at my previous picture of the switch you can see that the wire color is green, brown, blue. And on the oppsite side it is white/green, white/brown, white/blue. So in my case I soldered together the green and white/blue, and I also soldered the blue and white/green. I left the brown and white/brown alone for now.

Step 13: Solder Wires

Picture of Solder Wires

Take the 8 core wire and strip it back about 6 inches. Cut off two of the of the 8 cores because you only need 6, two for each motor/switch pair. Solder each color to one of the lines you soldered in the ast stem. In the picture above you can see that I soldered the blue and the white/blue from the 8 core peice to each pair of wires.

Step 14: Solder Power Suply

Picture of Solder Power Suply

Cut off the end of the power supply and strip the outside and inside wire. There should be a mass of wire in the cord and a smaller wire strand inside that. Take all of the brown wires from the switches and solder them to the mess of wires on the outside, then solder all of the white/brown wires from the switches to the inside set of wires.

Step 15: Secure Connections

Picture of Secure Connections

Where ever you have wires/solder on the sub tape over it to secure it, and make sure none of the wires are touching each other or the whole thing could short. Also I would sugust tapeing some of the cords together for better cable management.

Step 16: Insulation

Picture of Insulation

One of the most important thing is the insulation on the sub this is because it keeps the sub balanced as possible and to do this step you will need tube insulation the you can wrap around something and seccuris cut the insulation at about 5 inches the cut directly on the middle making it where it can open and wrap it around the desired spot and use zip ties on each end to keep it stable so it won’t float away. You might have to test it out a bit to get a good feel for what the bouabncy should be.

Step 17: Magnet

Picture of Magnet

Drill a hole into the cap of the sub and secure a magnet t the sub with a screw.

Step 18: Controller

Picture of Controller

Take a peice of wood and drill three holes into it that are about the size of the switches. The size of the wood is entirely personal preference. The switches should ahave a nut on them that you can unscrew and then use to secure them to the peice of wood.

Step 19: Test

Picture of Test

Try out the sub. If it doesn't work look over the steps agian.

Comments

rafununu (author)2017-02-02

It certainly works in a 10cm bathtube, it won't deeper. But that's fun anyway, bravo.

Actually, our sub was built with about 30 feet of wire extending from the controller. The power supply and controller must remain on land or you risk shorting. Theoretically, it could work in depth of up to 30 feet, however we wouldn't recommend that. The max depth we've tested the sub was in a pool 10 feet deep, where it was successful. Buying a longer wire would let the sub travel even deeper, and the sub would work until the point the water pressure was so great that it would cause water to leak into the motor casing. We're not sure what the depth our sub is capable of but it works in fairly deep environments.

I am part of the team that designed and built this btw.

tomatoskins (author)2017-02-01

I love your technique for waterproofing the motors! How long did this take to make? Were there any improvements you'd suggest for anyone else making this?

I built it with my group at school for a projet over the course of about two weeks. Make sure all the connections are secure and workng. Test them as you go because if one breaks at the end it can be hard to find.

This submersible was actually a school project that we built with a team. It was a fairly quick build, we spent about three weeks on it (no weekends and usually only an hour per day). I'm sure this could be easily built in only a few hours, however.

As to your second question, I would recommend a few things. First, use just a little bit more wax while water proofing the motor, during one of our tests we noticed one motor wasn't working as well. We opened it up and discovered some water had leaked in and we had to dry it out. IMO it would've been better to use electrical tape on the insulation instead of zip ties, with the zip ties the insulation tends to move around slightly. Finally I'd make the controller a bit more comfortable either sand it down or add some insulation to the sides, we still might do this actually and I'll be sure to let the viewers know.

dylan.darveaux.1 (author)2017-02-01

Hey, we decided to make a slight change to the submersible. The insulation on the side of the sub has been moved to be on the top side of the sub and more towards the front to deal with an issue of the sub sometimes turning on it's side, unable to flip back over.

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