ROBOT ARM CONTROLLED BY MUSCLE TENSION BASED ON ELECTROMYOGRAPHY AND PIC18F4550 Ricky Fajar Adiputra 1 ) dept. Of Electrical Engineering UNIKA SOEGIJAPRANATA Semarang, Indonesia rickyhacker@gmail.com Florentinus Budi Setiawan 2 ) Dept. Of Electrical Engineering UNIKA SOEGIJAPRANATA Semarang, Indonesia fbudisetiawan70@yahoo.com Abstract—Along with the progress of time, the application of science of robotics is also growing and starting to get the shares in many fields, especially the biomedical field that will be very beneficial to mankind's survival. In this thesis the writer will discuss the design and application of electromyography or more commonly known as gauges muscle tension to move the robot arm with the aid of a microcontroller PIC18F4550, with this final project the writer transforms muscles signals that are usually presented in the form of graphs or audio into physical form of movement using a robot arm. Keyword: Electromyography , PIC18F4550 , Rectifier , Servo , Robotic Arm , Amplifier. I. PRELIMINARY Today's modern technological development has been growing very rapidly and play an important role in the daily basis on human life, including the mechanics and electro medical sector, both of those knowledge could help people with disabilities such as who has lost their motoric function and then replaced with electronic motor in the form of robot arm. One of the options that can be used to be utilized by electro-medical system is a muscle, the muscle still can be utilized by reading the state when it’s contracted for when someone has lost their arm due to amputation. The left over muscle from an amputated arm can be used to move the robot arm by some processing invloved. By the time the muscle contracts, it will generate impulse signals that can be read by electrodes which can then be amplified and later on processed though a microcontroller for controlling robot arm with servo motors. II. THEORETICAL BASIS Before going any further into the discussion of how the design are made, the first thing to be understood is the origin of the voltage signal which is to be read by the electrodes attached to the skin surface, this voltage signal occurs by the process of polarization and depolarization of two most important Ion in the muscle cells, these ions are sodium (Na +) and potassium (K +), the occurring process of voltage is divided into 3 parts, namely Polarization (flexing), Depolarization (muscle relaxation), and Resting condition[1]. The following is an explanation of each phase and the impact on the readout signal voltage: • Resting Phase : In this phase occurs a balanced circulation between sodium (Na+) and potassium (K+) ions and in the theory, muscle cells produces -80mV. • Depolarization : In this phase the muscle contracts and the sodium ion displace the potassium ion from outside into the muscle cells in a larger portion in compared with the release of potassium ion from the inside of a muscle cells, During this displacement process of the ions through the cell membrane of a muscle, there are voltage fluctuations on the muscle cells by 120mV. • Polarization : In this phase occurs relaxation of the muscles resulting a displacement of sodium ions to the outside of muscle cells with greater proportions than potassium ions that enter the muscle cells, in theory this process gradually decrease the voltage back to - 80mV. With the above theory, then a simple flow chart was made to illustrate a simple signal processing process to be easy to work with the microcontroller. Proc. of 2016 3 rd Int. Conf. on Information Tech., Computer, and Electrical Engineering (ICITACEE), Oct 19-21 st , 2016, Semarang, Indonesia 978-1-5090-0890-2/16/$31.00 c 2016 IEEE 37