Project 2 Part 4: Iterating on the Mechanism

My main focus at this point was finalizing my mechanism. I 3D printed the posts for my rope holder platform as well as a duplicate of the platform itself. One of the platforms would serve as a base with ready-made slots for the posts, and the other would move with the rope. Luckily, the 3D printed posts had much less friction, but still enough integrity to stop the platform from moving left and right or forward and backward.



I ended up having to reprint my cams because the arms on the first version snapped off. I added a taper to the arms to increase their strength. I also tried adding set screws, but the holes were too small. The central hole for the shaft on the second version of the cams was also too big, so I tried resin printing some plugs for the cams so that they'd fit on the shaft. This didn't work super great because I had to break the plugs a little to get them to fit, but ultimately it made it possible for the cams to be super glued to the shaft.


I also printed and assembled the frame for the crab pot. There was a hidden slot in the bottom to put something to weigh down the pot. I thought about 3D printing or laser cutting some crabs to put inside the pot.


In the video you can see the cams, the crab pot, and the rope holder. I also added some wooden pieces to the rope holder to create jutting-out pieces that the arms of the cams could push down on. I made them of balsa wood to have a good balance of structural integrity and minimal weight.

I also needed to create a gear system to translate the movement of the motor into the rotation of the shaft. I definitely should've prioritized this part much more. I didn't give much thought to the fact that I needed the shaft to spin pretty slowly, so the gear attached to the motor needed to be much smaller than the gear attached to the shaft. I ended up having to remake my gears and I decided to laser cut them. 




In the video below you can see the mechanism working fully motorized. The crab pot was too big and was interfering with the mechanism, so I swapped it out for some random objects to use as weight. This worked well, and I noticed that the items (scrap metal and a roll of electrical tape) looked like garbage being pulled out of the water. I decided to drop the crab pot idea and keep the assortment of items as my weight. 
















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