This paper describes the design concepts andimplementation of a 5-Joint mechanical arm for a rescue robot namedCEO Mission II. The multi-joint arm is a five degree of freedommechanical arm with a four bar linkage, which can be stretched to125 cm. long. It is controlled by a teleoperator via the user-friendlycontrol and monitoring GUI program. With Inverse Kinematicsprinciple, we developed the method to control the servo angles of allarm joints to get the desired tip position. By clicking the determinedtip position or dragging the tip of the mechanical arm on thecomputer screen to the desired target point, the robot will computeand move its multi-joint arm to the pose as seen on the GUI screen.The angles of each joint are calculated and sent to all joint servossimultaneously in order to move the mechanical arm to the desiredpose at once. The operator can also use a joystick to control themovement of this mechanical arm and the locomotion of the robot.Many sensors are installed at the tip of this mechanical arm forsurveillance from the high level and getting the vital signs of victimseasier and faster in the urban search and rescue tasks. It works veryeffectively and easy to control. This mechanical arm and its softwarewere developed as a part of the CEO Mission II Rescue Robot thatwon the First Runner Up award and the Best Technique award fromthe Thailand Rescue Robot Championship 2006. It is a low cost,simple, but functioning 5-Jiont mechanical arm which is built fromscratch, and controlled via wireless LAN 802.11b/g. This 5-Jiontmechanical arm hardware concept and its software can also be usedas the basic mechatronics to many real applications.