The use of a real time application interface (RTAI) under Linux is very advantageous in the electrochemistry laboratory, owing to the development of experimental devices that allow us to take decisions or actions in situ, and also provide feedback. This device was successfully applied to the particular case of chronopotentiometry to stop experiments or to invert the sign of the applied current, in order to minimise the undesirable effects of charge of the double layer capacitance and to compensate the uncompensated ohmic drop. Moreover, digital simulation of double layer charge effects was also carried out. A schematic description of the software driving the device is given. (C) 2004 Elsevier B.V. All rights reserved.