Improving Haptic Feedback on Wearable Devices through Accelerometer Measurements

Many variables have been shown to impact whether a vibration stimulus will be perceived. We present a user study that takes into account not only previously investigated predictors such as vibration intensity and duration along with the age of the person receiving the stimulus, but also the amount of motion, as measured by an accelerometer, at the site of vibration immediately preceding the stimulus. This is a more specific measure than in previous studies showing an effect on perception due to gross conditions such as walking. We show that a logistic regression model including prior acceleration is significantly better at predicting vibration perception than a model including only vibration intensity, duration and participant age. In addition to the overall regression, we discuss individual participant differences and measures of classification performance for real-world applications. Our expectation is that haptic interface designers will be able to use such results to design better vibrations that are perceivable under the user's current activity conditions, without being annoyingly loud or jarring, eventually approaching ``perceptually equivalent' feedback independent of motion.