Build a Robot Arm and Controller

The Build a Robot Arm and Controller system functions by translating control commands from an Arduino Nano into precise mechanical movements across five degrees of freedom (5 DOF). The physical structure relies on the DFRobot 5 DOF Robotic Arm Kit, which includes structural brackets, bearings, hardware, and specific actuators: Hitec HS-311 servos, DF Metal Geared 15Kg servos, and a DF05BB servo. Because an Arduino Nano microcontroller has limited native PWM pins and limited onboard power handling for multiple servos, a PCA9685 PWM module is integrated into the circuit. The Arduino Nano communicates with the PCA9685 module using the I2C communication protocol, sending digital commands that dictate the desired pulse width for each servo channel. The PCA9685 then generates the corresponding 16-channel Pulse Width Modulation (PWM) signals independently, driving the Hitec HS-311, DF Metal Geared 15Kg, and DF05BB servos to exact angular positions. By coordinating these PWM signals, the various joints of the robotic arm—ranging from the high-torque base and shoulder joints utilizing the 15Kg metal-geared servos to the lighter wrist and gripper joints—move smoothly in tandem. Assembled using a #1 Phillips screwdriver and pliers, the entire electromechanical system allows undergraduate engineering students to program complex multi-axis motion sequences via the Arduino IDE.