We have reached the last mechanical phase of dimmer, i will explain how I made the wrist.
This part took me a lot of work, since the arm had to pick up one kg but moving with precision. To do this, I designed the wrist with two axes. One of rotation and other to go up or down.
I joined the clamp (bought by Internet, looking robot gripper) with a square profile of 10 x 10 millimeters. This frame will go inside of a cylindrical frame, and this frame is hold to the other frame that goes up and down.
After this i joined the servos. For vertical movement I used two Hd 1501 MG servos, with a torque of 17 kg-cm, while I used two MG995 servos of 11 kg-cm of torque for rotation.
Finally, I attached Hd 1501 MG servos to the structure and set the MG 995 to the cylindrical frame.