Week 15 – Final Day!

Now we have arrived at the final day before the final technical review!

With lots to be done, we arrived at the workshop early at 10am to get started, braving the heat in the workshop due to the air conditioners not being scheduled to turn on.

The very first thing we did was cut new metal pieces to align the spool to the main motor frame while 3D printing propellers which we found online: https://grabcad.com/library/propeller-85. We modified the file slightly to be able to fit onto our DC motor’s axle well.

Upon preparing the new metal pieces, we tested out the spool once more, and it coiled up perfectly except for one tiny problem – the rope, as it coiled up, tended to slip off the spool onto its axle, which caused the mechanism to jam up and the motor to stop turning. As such, we needed to limit the horizontal shifting of the rope on the spool. Regardless, we got the most crucial part done – getting the spool to work, adhering to at least 90% of our expectations.

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After we settled that, we moved on to ensure that the bicycle brakes were installed properly. As we did not have any welding tools at our disposal, we had to resort to using duct tape to secure the bicycle cable onto the main vessel. We had to make sure that the bicycle brakes were mounted in the correct position and hence we had to test it out by holding the vessel up and actuating the brakes with the servo motors. It was very troublesome as our vessel had 2 containers hanging down, wires connected to the motors, and our vessel wasn’t exactly light so it was quite an arduous task for us to carry out.

Nonetheless, we did it successfully and managed to actuate the brakes electronically using the servo motors.

Upon verifying that all the components worked individually, we then hooked up the rest of the electronics to the main board and mounted it on the top of the vessel. With time running short, we had to ensure that we were as efficient as possible when carrying out the final tasks. We coiled up the various sets of wires using the hand drill and subsequently ran the propeller motor wires through a transparent plastic tubing so as to keep it waterproof.DSC_3504

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However, once we connected everything up, we noticed that the Arduino board was not turning on. Murphy’s Law struck – Whatever can go wrong, will go wrong. We troubleshooted the problem and discovered that the VCC and GND ports of the board were somehow shorted. We traced the wiring, ensured it was all securely in place and tested the board again, and it worked fine.

The final part – controlling it via Bluetooth – Ajay finished up at home. We unfortunately were unable to test it out on water to see if it floats as the pipe system we sealed off came apart, the silicon sealant we used started cracking and the pipes hence detached from one another in the process. As the sealant takes about a day to dry, we decided to wait until after the final technical review to seal it off once and for all.

In conclusion, the day was very fruitful and we were very effective throughout the day. Despite the many setbacks we faced, we managed to complete a lot of tasks – although still not meeting our expectations. We will still push forward to complete it by the end of the coming week, Week 16.

Thomas Wong

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