Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive neuro-imaging methodused to measure brain activity. The main advantage of this method is its high mobility and movement tolerance. Studies can be conducted where the subjects need to move freely and can not be restricted by a large and heavy measuring apparatus. The system uses a combination of infrared LEDs and photodiodes called optodes that measure the concentration changes of oxygenated and deoxygenated hemoglobin, which are directly correlated to the oxygen saturation associated with neural activity. These optodes are connected to a mainboard using cables that add to the weight of the system and risk shifting the optodes on the head of the subject during movement. To minimize the need for cables connecting the optodes to a mainboard, the fNIRS system described in this thesis uses autonomous, modular optodes connected on a grid. The first drivers for the microcontrollers located on each optode are build and tested in this thesis.