Hello 
I have made the PCB  for the hand the same as yours, not using the expansion I/O board now . this is my third attempt second on perf board. I can get the switches working and the LED's switch modes, but I cant get the servos to operate. as you said I have used two power supplies, one to the Nano and the other to the servos. 
The first attempt the Nano got so hot but not a wiring problem ???
The second attempt was on hookup board this runs cool led's and switches work etc. but still no servo moment.
Can you tell me poss why and what do all the switches do.

Is there a mode that operates each finger  manually.
Mike

Thank you for the excellent design! What is the maximum load it has sustained?

Man, What is that thing you use to merge nylon wires???

Hi, Thank you for the really great design!  I am trying to make this project but the bottom joint of finger I have printed out doesn't seem to have anything to stop it when it is straight.  I.e. it goes all the way back when you pull the string to straighten it.  Is there any way to stop it doing this please?

I used a piece of wire glued to both ends to stop it from going to far

what about the old coding..?arduino? Plesee

Old coding?

Hi I am Midhun from India(kerala). I am doing final year EE. I am doing prosthetic arm as my final year project i could see these links are pretty useful.

How about your taking feedback from current sensor. Which sensor did you take for the same?

Hello,

My name is Kumar Simms and am a student work study at Community College of Allegheny County. Learning to put this together and would love if I could ask questions I have of the smaller details through contact. My email is kumar.simms@acd.ccac.edu.

I like this project very much!  I'm a left hand amputee myself, and I'd like to build this and try it out.  Are there assembly instructions?  The video moves much too fast to follow.

Hello Isaac. I'm sorry i missed your comment. It would be great if the prosthesis could help you! How's the build going? If you have any questions about the project, you can always send me a private message. Best regards, Brian

Hi, My son and I built a very similar project for a prosthetic hand competition.  We found several advantages to using gear motors (strength, torque, size ..) similar to this:  https://www.ebay.com/i/311900465658?chn=ps

And we were able to use back EMF to measure force / speed using the method outlined here: https://robidouille.wordpress.com/2009/09/20/back-emf/ 

I'm not and EE but it was very effective and worked well for us.

Very nice and thank you very much for the links. They are quite usefull.

Congratulations i like your project.

Thank you Sinan Caglan!

Keep going i really like your project

Thank you very much alpha le ciel!