Binary pulsars can serve as natural dark matter detectors. We consider an ultralight scalar dark matter, which interacts directly with the binary pulsar components via a universal effective interaction, characterized by one coupling constant. This causes a perturbation of the dynamics of the binary system. The perturbation is manifested by a change in the arrival time of pulses from the pulsar on Earth. The aim of our work is to determine the limiting value of the coupling constant, enabling the measurement of this effect. In other words, time residuals can serve as a proxy for ULDM. In this proceedings, a simple approach to sensitivity curve construction (i.e., a plot of the coupling constant versus particle mass) is presented. Further details and a comprehensive analysis can be found in [1].