Problems... (Week 8)

Due to the Memorial Day Weekend, not much was accomplished in regards to the submarine. Most of the basic programming is complete, so we are not focused mainly on it. If any modifications are needed in our current system, they can be easily programmed. Our electrical system and control system, in hand with the programming, are also almost finished. So, with that, the main thing we are trying to focus on is keeping the electrical wiring and the submarine completely waterproof. 


Waterproofing the submarine is going to be tougher than we anticipated mainly due to the fact that it can be hard to discern where the leaks are occurring. We tried to do an experiment to find the leaks with the idea that there would be few leaks. The result was that the whole submarine was filled more than halfway with water. Obviously, we can't have that being that the point of a submarine is having it underwater. This is why waterproofing has been a main focus; we don't want to have any of the electrical components to be damaged when the submarine goes for its first dive. 

Painted (Week 7)

Since the previous post, the group has been able to accomplish a decent amount of work for the submarine. We began to seal the area where our main wires go through. We should be able to finish the job throughout the week, bringing us another step closer to waterproofing the submarine. Our programmer has also been able to program the gyroscope into giving the angular velocity of the submarine. Since we prefer the angle, he plans on solving a differential equation in order to find a function for the angle, which he can incorporate into his program.

What we plan on doing throughout Week 8 involves ballasting the tank. We plan on using bags of sand placed in the front and the back of the sub as ballasts. The only problem is we need to figure out an easy way to adjust the bags of sand without reaching in all the way into the back. We are also waiting for our USB extender to arrive so we can transmit a signal over a long wire. After we successfully ballast the sub, we have to start testing for any leaking we didn't cover and if our control system is successful underwater.


We were also able to paint the whole outside of the sub. Pomo, who did an excellent job painting it, equipped the sub with a black and yellow covering with the Drexel dragon on the side.

Drexel Lettering on the side.

Drexel Dragon on the side.

Trouble In Communication... (Week 6)

A fairly decent amount of work was done throughout Week 6. By using SPI (Serial Peripheral Interface) communication to "talk" to the gyroscope, we have been able to program the device into returning output values. In other words, when the gyroscope moves, the returning numbers change. The only problem with these numbers is that we do not really know what these numbers mean. So we are currently working on a way to solve this problem in communications.

Mechanically, we have installed a set of "rails" along the insides of the submarine in order to hold the gyroscope board and the main board. We have also modified the cap so that it can be waterproof while still having an Ethernet cable plugged in. We were able to do this by installing a waterproof Ethernet receptacle, which will allow us to plug in the Ethernet cable while blocking the access point the water would have normally had. We have also set up a system that allows us to plug in and disconnect each motor individually. This was required since the twelve-pin connector was unable to fit into the receptacle. And finally, making the Ethernet cable perfectly buoyant is still a work in progress, but we plan on using pool noodles cut up into individual pieces in order to do this.

They're In... (Week 5)

The gyroscope and the accelerometer finally arrived on Friday. As stated numerous times in previous posts, what we plan to do with the gyroscopes and accelerometer is hopefully program a way for the submarine to measure what "angle" it is currently at in relation to its "leveled" state. From this, it will be easier to control the submarine into moving into an angle of zero degrees. The programming for the gyroscope has already been started and the gyro has already been connected to our system.


Waterproofing is still in progress as we need to be sure that there won't be any leakage infiltrating the submarine and our waterproof plugs have not come in yet. We simply need to do some tests in order to see if our system is successful. Since we are using an Ethernet cable in order to control the submarine, we need the cable to remain buoyant in order for it to not drag on the floor. We also do not want the Ethernet cable to be floating on the surface, so what we are using are pool noodles, which, if cut right, gives an almost perfect buoyancy. The reason we want perfect buoyancy for the cable is so it does not drag the submarine along with it.


So, in essence, what we plan to do in Week 6 is to perfect the buoyancy of the cable, finish the programming for the gyroscope, and test the current systems for waterproofing.

Waiting... (Week 4)

This week was not very eventful in comparison to the previous weeks. Programming and waterproofing the submarine are still works in progress. As mentioned in the previous post, we were able to fully control the motors with a tank control scheme. However, things are at a stop at the moment as the items we ordered have not arrived yet.

What we have ordered are items that will be mainly used for waterproofing the submarine. We ordered an Ethernet waterproof plug. We also ordered a gland, which is a device that prevents "leakage of fluid along a rotating shaft." A gyroscope was also ordered, and with it we plan on using it to help orientate the sub underwater.

Like I said, nothing much happened during Week 4, but hopefully most of the materials we ordered will come in during Week 5 so we can get back to working on our goals.

It Lives... (Week 3)

Since the last post, a lot was accomplished in regards to the programming and the electrical components. With the Arduino microcontroller, we were able to control the six motors with an Xbox 360 controller. The submarine is controlled in the style of a tank, which means we will have full control as it moves forward or backward while rotating. This was important as we wanted a control system that was user friendly and easy to program at the same time.

The current control scheme for the sub.

With the way the controls are set up, we have to be careful that we don't rotate the sub at an improper angle from the x-axis. In order to counteract this, we decided to use an accelerometer alongside a gyroscope to give details of the sub's angular position. By the end of this, we are hoping for the controls to include a button that will simply level the sub automatically.

Two of our group members were able to fit the inside of the submarine with brackets that will allow easy access to the electrical system when the time comes to replace the battery. The waterproofing is still in progress but nearly accomplished. It turns out that we do not need a gasket since the "cap" at the end of the sub is already tight enough to prevent any leakage coming through. Right now we are seeing how waterproof plugs work and if we can incorporate them into the system.

You can see the "brackets" near the top of the image.

Gasket Needed! (Week 2)

As of right now, the submarine is completely dismantled (except for the motors attached to the hull of the submarine.) In relation to Arduino, the Shield, which is an expansion that increases the capapilities of the microcontroller, is now connected. The next step is for the Arduino microcontroller is to simply see if we can get a signal to the motors.

For the "capsule" part of the submarine, one of our group members thought of installing some brackets that will support a platform that will allow convenient access to the electrical components.

Another problem that has come up is that now that the seal from the cap has been broken, we need to figure another way to make the submarine water-tight. Taking measurements of the inner and outer diameter of the "capsule," we figured that we can use an O-Ring in order to seal the cap and yet allow for easy access to the elctrical components.

In regards to the programming, our programmer was able to download a compiler. What this compiler does is break down a code into a binary code (i.e. 10111001) that the microcontroller will understand. What he has to do is figure how the Arduino microcontroller will understand inputs from an Xbox 360 controller.