This paper describes a method for determining the quasi one-dimensional burning velocity for gas explosion experiments in a smooth tube from pressure records. A one-dimensional random choice method code (RCMLAB) has been written in MATLAB. The combustion model in RCMLAB treats the combustion wave as a discontinuity. For a given burning velocity S(t), we can find the weak deflagration solution and calculate the flow field. This allows us to estimate S(t) from the measured pressures. This was done using a proportional controller with the difference DeltaP between estimated and observed pressure as input and the time derivative of S as output. The experimental setup consists of three tubes with a diameter of 22 mm and lengths of 1, 2, and 5 m. The tubes were filled with premixed stoichiometric propane/air. The model for determining the burning velocity for a gas explosion in a smooth tube seems to work quite well.