Digital Micromirror Device (DMD) is a commercial and mass-produced Micro Electromechanical System (MEMS) spatial light modulator (SLM) consisting of millions of mirrors that spatially modulate lights by switching it between on and off states. Between the on- and off-states, transitional states exist where micromirror changes tilt angle. We report a method to control the transitional time of the mirror array by controlling the pressure of the ambient air. The increased air pressure to 100 psi increases mirrors transitional time by 20%. We also address the possibility of controlling the transitional time electrically.