The arm is able to lift more than 1kg (the grapefruit has 1008 grams).
The arm was printed with an ORCA 0.3 printer with PLA.
Total weight of arm is 360 grams (including motors).
Heigth of the arm is 38 cm.
Servo motors costs about 300 Euros (2x HS-7980TH and 1xHS-7985MG).
For controlling the motors I use a SSC32 board from lynxmotion.
Everything is powered by a acid-lead battery of 6V, 12 Amps (costs about 50 euros).
A video is here:
Old attempts are here (smaller objects are lifted):
this is the first attempt, where a small apple is lifted.
this was the 3rd attempt where I lifted an 310 grams orange. Because the gripper was constantly slipping I have created a larger one. Also the shape was changed to be circular for holding spherical objects better.