Perceived Vibration Strength in Mobile Devices: The Effect of Weight and Frequency.
ABSTRACT This paper addresses the question of strength perception for vibration signals used in mobile devices. Employing devices similar to standard cell phones and using pulsed vibration signals to combat adaptation effects, experiments were performed to study the effect of weight and underlying on perceived strength. Results shows that for the same measured acceleration on the device, a heavier box is perceived to vibrate with greater strength. Furthermore, signals with higher underlying frequency are perceived to be weaker for the same measured acceleration. While our results are consistent with previous studies, they are obtained for the specific condition of ungrounded, vibrating objects held in the hand. Our results suggest the need for a systematic correction law for use by designers to specify the vibratory characteristics of a device as a function of its weight and of the desired operating frequency.
Conference Proceeding: Perceived Magnitude and Power Consumption of Vibration Feedback in Mobile Devices.[show abstract] [hide abstract]
ABSTRACT: This paper reports a systematic study on the perceived magnitude of vibrations generated from a vibration motor fastened on the user’s thenar eminence and its electric power consumption. The vibration motor is widely used in mobile devices for vibration feedback due to its small size and inexpensive price. However, a critical drawback of the vibration motor is that the amplitude and frequency of vibrations generated from it are correlated due to its operating principles that allow only one control variable (applied voltage). Motivated by this fact, we have investigated a relationship between the perceived magnitude of vibrations produced by the motor and its power consumption with the applied voltage as a common parameter. The results showed that using more power does not necessarily increase the sensation magnitude, which indicates vibrations of the same perceived magnitude can be rendered while extending the life span of a mobile device battery.Human-Computer Interaction. Interaction Platforms and Techniques, 12th International Conference, HCI International 2007, Beijing, China, July 22-27, 2007, Proceedings, Part II; 01/2007
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ABSTRACT: The human capacity for vibrotactile frequency discrimination has been compared directly for glabrous and hairy skin regions by means of a two-alternative, forced-choice psychophysical procedure in five subjects. Sinusoidal vibratory stimuli, delivered by means of a 4-mm-diam probe, were first used to obtain detection threshold values for the two skin sites, the finger tip and the dorsal forearm, at four standard frequencies, 20, 50, 100, and 200 Hz. Values confirmed previous results showing detection thresholds were markedly higher on hairy skin than on glabrous skin. For the discrimination task, each standard frequency, at an amplitude four times detection threshold, was paired with a series of comparison frequencies, and discrimination capacity then was quantified by deriving from psychometric function curves, measures of the discriminable frequency increment (Deltaf) and the Weber Fraction (Deltaf/f), which, when plotted as a function of the four standard frequencies, revealed similar capacities for frequency discrimination at the two skin sites at the standard frequencies of 20, 100, and 200 Hz but an equivocal difference at 50 Hz. Cutaneous local anesthesia produced a marked impairment in vibrotactile detection and discrimination at the low standard frequencies of 20 and 50 Hz but little effect at higher frequencies. In summary, the results reveal, first, a striking similarity in vibrotactile discriminative performance in hairy and glabrous skin despite marked differences in detection thresholds for the two sites, and, second, the results confirm that vibrotactile detection and discrimination in hairy skin depend on superficial receptors at low frequencies but depend on deep, probably Pacinian corpuscle, receptors for high frequencies.Journal of Neurophysiology 04/2006; 95(3):1442-50. · 3.30 Impact Factor
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ABSTRACT: Vehicle drivers receive tactile feedback from steering-wheel vibration that depends on the frequency and magnitude of the vibration. From an experiment with 12 subjects, equivalent comfort contours were determined for vertical vibration of the hands at two positions with three grip forces. The perceived intensity of the vibration was determined using the method of magnitude estimation over a range of frequencies (4-250 Hz) and magnitudes (0.1-1.58 ms(-2) r.m.s.). Absolute thresholds for vibration perception were also determined for the two hand positions over the same frequency range. The shapes of the comfort contours were strongly dependent on vibration magnitude and also influenced by grip force, indicating that the appropriate frequency weighting depends on vibration magnitude and grip force. There was only a small effect of hand position. The findings are explained by characteristics of the Pacinian and non-Pacinian tactile channels in the glabrous skin of the hand.Applied ergonomics 09/2008; 40(5):817-25. · 1.11 Impact Factor