METHODS AND APPARATUS TO MONITOR HAPTIC VIBRATIONS OF TOUCHSCREENS

Methods and apparatus to identify haptic vibrations of touchscreens are disclosed. Example apparatus disclosed herein obtain a haptic control signal that is to cause vibrations of a touchscreen to simulate a texture corresponding to visual subject matter to be displayed on the touchscreen, the vibrations of the touchscreen to produce an acoustically detectable signal. Disclosed example apparatus also encode a watermark into the haptic control signal to generate a watermarked haptic control signal, the watermark including identification information to identify at least one of the subject matter or the texture, the watermark to modify the acoustically detectable signal.