Robotic arm is control of servo so you can find here how to control servo with 89c51 https://www.engineersgarage.com/microcontroller/8051projects/servo-motor-project-circuit
and for structure you can made yourself via wood or buy online .
Robotic arm is control of servo so you can find here how to control servo with 89c51 https://www.engineersgarage.com/microcontroller/8051projects/servo-motor-project-circuit
and for structure you can made yourself via wood or buy online .