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Back on the electronics again. Have been going over my BLDC motor schematic and making some little tweaks to it. Here's the updated schematic. It's a combination of lots of other schematics I've found online as well as some chatgpt help. With 1 being no clue and 10 being absolute expert tier in...
I installed two tensioners for the robot and they were seriously successful overall in testing. So much so that I am now confident enough in the entire pulley system to move onto the custom mini BLDC motor controller to get the motor to run motorized tests of finger movements next. Well after a...
Okay so the bracelet cord self untied quickly so I'm going back to my previous approach of tying off both ends of the bracelet cord with a fishing crimp sleeve.
While trying to cut in half fishing crimp sleeves with my mini miter saw I noticed it was a difficult process and not ideal. So I came...
Ok I figured out a bit easier way: tie a knot at each end of the strip of bracelet cord and then tie my nylon thread off onto the bracelet cord inside that bracelet cord knot. The bracelet cord knot on each end acts as an endstop. Seems to work great so far and cuts down on materials this way...
I figured out a robust way to make the extension cord for finger extension using the bracelet cord and a fishing crimp sleeve. The idea is to crimp the two ends of a folded in half strip of bracelet cord and this way both ends can be sewn down into the fabric without any gluing which could...
So in recent testing a fresh issue I ran into was the TPFE tubing would start gradually pulling through its tightly wrapped tape sleeve to my surprise. Its low friction surface gradually pulls free of the tape over time. To resolve this, I decided to thread through the tip of the tubing to...
The tension spring mounted to the motor setup upon further testing seems like a somewhat bad method. The issue I'm having is too much play in the tubing running between that spring and the finger joint. When tension is applied to that spring by way of the tubing, the tubing recoils and moves...
I finally finished making the tensioner mechanism for the winch in place pulley and I taped it off up the string descending from the ceiling and taped the far end of it onto the ceiling. I noticed I have to keep it as straight as possible since when curling with too much turning the elastic...
Minor update: I have now carefully mounted the PTFE tubing that leads to the elastic string tensioner for the winch in place pulley. I mounted it snugly to the side of the PTFE tubing coming off the same winch in place pulley that leads to the Archimedes pulley system. I routed both of these...
Sometimes to get the braided PE fishing line threaded through the fine PTFE tubing can be tricky, so I came up with a neat device to assist in this. I will be making a threading tool based on a needle threader tool I've been using. It's basically a wire folded in half that you shove through a...
Ok so I currently have an order for 0.2x1x1000mm tension springs stuck in customs for weeks and placed another order just today for the same in hopes it goes through faster. But at $9 for a single spring that is 3ft long, I am feeling RIPPED OFF on price. It is bullcrap. All relating to the...
Good news: I had mentioned before I was planning to use 2mm OD tension spring for the winch in place pulley tension solution but once I got the 3mm ID 4mm OD PTFE tubing to go over the spring, I saw that the 4mm was just WAY too big once you multiply that out to 300 motors. 300 of 4mm OD tubing...
After further consideration, I'm scrapping using the elastic cord for a bracelet idea (as a tension spring for the winch in place pulley). The point of that was to use as little space as possible but I just don't trust it. I am not sure what material it is made of and my experience with rubber...
Update: I bought several sizes of kevlar string to use to replace the PE fishing line particularly in the high tension areas that may face the highest durability challenges. I found it on amazon in many sizes. I just bought one of each size: 0.5mm diameter 50lb test, 0.8mm diameter 100lb test...
A note on fishing line durability. I think this was mentioned in passing quite a few times but at some point, a mention of durability concerns becomes that final mention that makes you really start to question it more and so I finally did some research on chatgpt and found out a human finger...
Ok so I did a big refactor of my pulleys and ran a test again and it still is not working. The first set of archimedes pulleys tops out and can't move anymore while the finger still hasn't moved. This is because of slack in the lines. I did not calculate slack in the lines into my calculations...
Here's progress on a return spring for extension of the finger after pulley system has caused it to grasp.
Here's my completed V2 archimedes pulley system finally done! It is 16:1 downgearing and this pairs with my 2.77:1 downgearing on the turn in place pulley on the motor for a total of 44:1 downgearing.
Here's a turn in place 2.77:1 downgear pulley I setup right next to the motor output shaft.
and here it is in testing:
