In this study, a FPGA based, mobile, fully autonomous, 5-DOF robot arm, which can distinguish objects according to their dimensions using an ultrasonic sensor module is designed and implemented. Digital hardware design of speed and position control of the vehicle carrying the robot arm and the position control of the robot arm are implemented on a single FPGA chip. The driver circuits of the DC motors and the RC motors mounted on the mobile robot arm system are also realized, and the motor speed and position controls are handled through the PWM signals obtained by a specific VHDL module. Frequency division technique is used to produce the PWM signals. The concurrent controls of the units mounted on the arm are possible due to parallel execution ability offered by FPGA based designs. The Modelsim program is used for VHDL code simulations. The real FPGA implementations are done on a Spartan-3 FPGA evaluation board using Xilinx ISE tools. This evaluation board is also mounted on the vehicle platform as a part of the mobile robot arm system. The test results show that the robot arm is able to accomplish all expected functions successfully. Finally, the designed robot arm is only categorically compared to some robot arm designs exist in the literature due to mismatch with design technology, robot type and DOF in all aspects.