Liao, Y.-CY.-CLiaoChen, Y.-LY.-LChenLo, J.-YJ.-YLoLiang, R.-HR.-HLiangChan, LLChanBING-YU CHEN2020-02-102020-02-102016https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995773240&doi=10.1145%2f2984511.2984522&partnerID=40&md5=ea77432fcfdf2c01412ae0ef1b97207dhttps://scholars.lib.ntu.edu.tw/handle/123456789/456312This paper presents EdgeVib, a system of spatiotemporal vibration patterns for delivering alphanumeric characters on wrist-worn vibrotactile displays. We first investigated spatiotemporal pattern delivery through a watch-back tactile display by performing a series of user studies. The results reveal that employing a 2×2 vibrotactile array is more effective than employing a 3×3 one, because the lower-resolution array creates clearer tactile sensations in less time consumption. We then deployed EdgeWrite patterns on a 2×2 vibrotactile array to determine any difficulties of delivering alphanumerical characters, and then modified the unistroke patterns into multistroke EdgeVib ones on the basis of the findings. The results of a 24-participant user study reveal that the recognition rates of the modified multistroke patterns were significantly higher than the original unistroke ones in both alphabet (85.9% vs. 70.7%) and digits (88.6% vs. 78.5%) delivery, and a further study indicated that the techniques can be generalized to deliver two-character compound messages with recognition rates higher than 83.3%. The guidelines derived from our study can be used for designing watch-back tactile displays for alphanumeric character output.conference paper10.1145/2984511.29845222-s2.0-84995773240