Finished making the mount

Ok, so I finally finished the mount, and it took a lot longer than I thought it would.

There were a lot of issues regarding the pulley system, so I decided that it was best to just ditch the pulleys at the base and switch to gears. The reasoning behind this is that the gears align much more easily, and the distance between the base and the motors is minor.

Another issue I ran into was how to package the motors properly. In the photos below, the motors are packaged nicelyish, but without mounts. I'll get the mounts created soon, as it isn't too hard.

Anyway, I'll get to designing the PCB and choosing the microcontroller now.

Started to create a basic CAD for the robotic arm.

Saturday, Oct 4
The first three-ish hours were researching which motors to use and how to build robotic arms. After a thorough deep dive, I began CADing the arm in Onshape. I had already designed a differential wrist before, so I used the CAD files for that, modified them a little bit, and boom, two degrees of motion down. The next issue was the claw that most robotic arms have. I chose a metal geared servo that weighs a hefty 56 g, but it provides an enormous amount of torque, and if I'm trying to increase the carrying capacity of this arm, then I'll need a stronger servo. The claw itself is just a four-bar linkage with a little bend at the end to make sure that you can get a decent grip. Next up was designing the arm. I split this into two sections: the first pivot section and the second pivot section. The first pivot section would connect to the base, and the second pivot section would connect to the first pivot section and also the differential wrist. This probably took the bulk of the time as I weighed the different pros and cons of increasing/decreasing the size and shapes of certain parts. Because the vast majority of the plates are going to be 3D printed to save cost and weight, the plates have to be sturdy enough. Another issue I ran into was the lack of bolt sizes. Most small bolts cap out at around 3in, which means that any gap in between the two plates needs to be less than 3in, or else I can't have supports running between them. I could use standoffs, but those aren't 3d printable, and designing the gap between the two plates to be smaller wasn't as hard. I have a photo of the progress so far below, and I still have yet to do the base, but that shouldn't take more than another hour. Another thing about my robotic arm is that it uses pulleys with ALL the motors mounted on the base, not at each joint. I originally wanted to use rope, but after a huge headache (and wasting two hours) attempting to make something close to a capstan drive, I gave up and settled on pulleys. Capstan drives are just a lot harder to make accurately, so for attempt one, I'm going to stick with pulleys.