Week 10

This week, we completed building our Sea Perch and even had some time to test. We had some issues with wiring the control box, but after some troubleshooting, we found that our fuse on the circuit board blew and the ethernet cable plug had some issues. Since we did not have an extra fuse and would have to make a run to Radio Shack for a new fuse anyway, we just bridged the connection on the control box and added a 10 amp inline fuse near the battery, as the instructions on some other Sea Perch kits describes. The the 10 amp fuse will also be less likely to burn out, because our last fuse was 6.3 amp. And if this 10 amp fuse burns out, then we have 3 extra fuses which will be easier to replace than the 6.3 amp fuse because this inline fuse does not require us to take the control box apart and re-solder the board to replace the fuse. For our ethernet cable plug issues, we ended up cutting the broken ethernet cable plug and crimping a new one on, which solved our problem. After we fixed all of our control box issues, we proceeded with final assembly.

First we glued our low speed motor to the bar directly beneath the rotating bar, and glued the small 8 tooth gears to the same motor. We then slipped the large 40 tooth gears and the gear holders to the rotating bar and aligned the gears in plane with each other using the lego chain. Once we had the gears aligned, we drilled the holes for the gear holders into the rotating bar and drilled the holes which would connect the 40 tooth gears to the gear holders. After we dirlled all of our holes, then we bolted everything together, added the chain, and tested the design. all seemed to go well at first, but we found that the plastic lego chain kept on breaking because the chain was either too tight or too lose. Since adding or taking away one link from each chain would result in the chain breaking, we created a chain tensioner using safety wire.

Chain Tensioner:

After we adjusted our chain tensioner, we found that the lego chain was working as planned, so the next day we took the Sea Perch to the pool to test it.

Sea Perch after final assembly:

The tests went very well. The Sea Perch did not break in any way, and the water proof motors worked flawlessly.


Speed Test: 

Maneuverability Test:

From all of our tests, the only issues we had was that our Sea Perch pulled to one side, which we predicted would happen after observing how one propeller wobbled when spun and the other propeller worked great.

We also finished our final report and final presentation and in the process of practicing our presentation.

Week 9

Accomplishments for this week:

-Completed waterproofing box for motor, installed motor.

Meet the new box. (Same as the old box.)

-Installed rotating pipe and attached motors.

Assembly nearing completion.

-Largely completed wiring.
-Assembled most of the ROV

Motors have since been attached.

-Completed designs for sprockets for the chain.

8-tooth gear for drive beam.

40-tooth gear for motor beam.

-Began to put together final presentation.

Goals for next week:
-Finish control box.
-Finish assembling and test the ROV.

Week 8

Accomplishments for this week:

-Received LEGO chain.
-Drilled holes for brackets in PVC piping. Attached the brackets.
-Began assembly of the control box.

Cutting wires for the control box.

-Created design for improved waterproofing box for the low-speed motor.

Designing the improved box.

Goals for next week:

-Assemble and test the whole thing.

Week 7

Accomplishments for this week:

-Finished waterproofing motors entirely. The low-speed motor's waterproof box was completed.

The motor in its box.

Work happening.

The other two waterproofed motors.

The box for the low-speed motor, sealed with silicone, and with holes drilled for the driveshaft.

-Ordered LEGO chain. All parts for drivetrain are now ordered.
-Started work on control box.
-Designed gears to be laser-cut at machine shop.


Goals for next week:
-Laser-cut gears.
-Finish control box.
-Initial assembly and testing.

Week 6

This week's accomplishments:

- The group has been given a servo motor from Drexel Hybrid SAE. The group is currently attempting to determine whether it would be easier to go with the servo than the low speed motor, and whether it is feasible to include it this late in the design.
The servo motor's ability to move to any arbitrary position would be invaluable, and would simplify controls down to just a potentiometer, but it may be too late to include it into the design at this point, as it would require new waterproofing boxes.
- Finished waterproofing motors.

The existing SeaPerch  motors, taped up and ready to go in their waterproof capsules.

The new motor in its waterproof box.

The box holds water from the inside, so presumably it also will keep out water from the outside.

- Finalized Solidworks design.

Figure 4: The belt system has been disregarded in favor of a system that uses LEGO chains to drive the center pole. This system will provide much more adhesion and should work much better underwater than a plain belt system would.

Next week's goals: Design propellers, fabricate propellers, assemble SeaPerch to the extent that it can be.

Week 5

This week's accomplishments:

- An extra low-speed motor was acquired, to move the center pipe which allows the SeaPerch to steer.

The new motor. It spins very slowly, largely because it is geared down so much.

- This motor has now been assembled and tested.
- A belt system has been designed to allow the motor to actually turn the center pipe.
- Continued working on Solidworks model. The new low-speed motor was mounted, as displayed in figure 3. This motor will drive the center pole through a belt.

Figure 3. Updated Solidworks model.

 Next week's goals: Finalize electrical systems, get a few more parts fabricated.

Week 4

Accomplished this week:
- Continued working on Solidworks model of SeaPerch. The model is now almost complete and comprehensive, containing every detail required for the construction which the group has worked out so far.

Figure 2: Changes so far: added mounting brackets for the motors, added the big red floaties on the top, added bushings for the center pipe where the belts will be.

- Finished a bill of materials for the submersible. Extra material was acquired from the Drexel Formula SAE team, because it was just lying around unused.
- Cut all PVC pipes to length to allow frame assembly to take place.
- Assembly of the SeaPerch frame was completed, proving that the modifications to the frame were workable.
- Aluminum brackets were fabricated, to allow the center pole containing the motors to rotate freely.

Bending aluminum around pipe to make a bracket. Safety was a priority in this fabrication procedure.

- Holes were drilled in PVC joints to allow water to enter the PVC pipes making up the SeaPerch frame, making it neutrally buoyant.

A drill press was used to drill holes into the PVC pipe fittings.

Next week's goals including finalizing the electrical system design and making the motors waterproof.