{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T14:45:07Z","timestamp":1778251507951,"version":"3.51.4"},"reference-count":17,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2018,3,1]],"date-time":"2018-03-01T00:00:00Z","timestamp":1519862400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this study, an earphone-type interface named \u201cearable TEMPO\u201d was developed for hands-free operation, wherein the user can control the device by simply pushing the tongue against the roof of the mouth for about one second. This interface can be used to start and stop the music from a portable audio player. The earable TEMPO uses an earphone-type sensor equipped with a light emitting diode (LED) and a phototransistor to optically measure shape variations that occur in the external auditory meatus when the tongue is pressed against the roof of the mouth. To evaluate the operation of the earable TEMPO, experiments were performed on five subjects (men and women aged 22\u201358) while resting, chewing gum (representing mastication), and walking. The average accuracy was 100% while resting and chewing and 99% while walking. The precision was 100% under all conditions. The average recall value of the five subjects was 92%, 90%, and 48% while resting, masticating, and walking, respectively. All subjects were reliably able to perform the action of pressing the tongue against the roof of the mouth. The measured shape variations in the ear canal were highly reproducible, indicating that this method is suitable for various applications such as controlling a portable audio player.<\/jats:p>","DOI":"10.3390\/s18030733","type":"journal-article","created":{"date-parts":[[2018,3,1]],"date-time":"2018-03-01T12:15:44Z","timestamp":1519906544000},"page":"733","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Earable TEMPO: A Novel, Hands-Free Input Device that Uses the Movement of the Tongue Measured with a Wearable Ear Sensor"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5774-5124","authenticated-orcid":false,"given":"Kazuhiro","family":"Taniguchi","sequence":"first","affiliation":[{"name":"Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozukahigashi, Asaminami-ku, Hiroshima 731-3194, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hisashi","family":"Kondo","sequence":"additional","affiliation":[{"name":"eRCC Co., Ltd., 21-3 Motomachi, Nakaku-ku, Hiroshima 730-8504, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8144-2270","authenticated-orcid":false,"given":"Mami","family":"Kurosawa","sequence":"additional","affiliation":[{"name":"Interdisciplinary Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5669-1726","authenticated-orcid":false,"given":"Atsushi","family":"Nishikawa","sequence":"additional","affiliation":[{"name":"Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan"},{"name":"Division of Biological and Medical Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"260","DOI":"10.20965\/jrm.2008.p0260","article-title":"KOMEKAMI Switch: A Novel Wearable Input Device Using Movement of Temple","volume":"20","author":"Taniguchi","year":"2008","journal-title":"Int. J. Robot. Mechatron."},{"key":"ref_2","unstructured":"Taniguchi, K., Nishikawa, A., Miyazaki, F., and Kokubo, A. (2015). Input Device, Wearable Computer, and Input Method. (8,994,647), U.S. Patent."},{"key":"ref_3","unstructured":"Taniguchi, K., Horise, Y., Nishikawa, A., and Iwaki, S. (2012, January 8\u201311). A novel wearable input device using movement of ear-canals. Proceedings of the 2012 5th Textile Bioengineering and Informatics symposium (TBIS), Ueda, Japan."},{"key":"ref_4","unstructured":"Kurosawa, M., Taniguchi, K., and Nishikawa, A. (2017, January 22\u201314). Earable: A Novel Earphone-type Wearable Sensor and Its Applications. Proceedings of the 5th Annual Conference of AnalytiX-2017 (AnalytiX-2017), Fukuoka, Japan."},{"key":"ref_5","unstructured":"Taniguchi, K., Kurosawa, M., and Nishikawa, A. (2017, January 21\u201324). earable: Wearable ear computer. Proceedings of the 2017 International Conference for Top and Emerging Computer Scientists, Taipei, Taiwan."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1109\/TITB.2012.2191793","article-title":"Quantitative and Comparative Assessment of Learning in a Tongue-Operated Computer Input Device\u2013Part II: Navigation Tasks","volume":"16","author":"Yousefi","year":"2012","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_7","unstructured":"Eugen, R.L., and Struijk, L.N.S.A. (2008, January 13\u201315). Design of Inductive Sensors for Tongue Control System for Computers and Assistive Devices. Proceedings of the 2nd International Convention on Rehabilitation Engineering & Assistive Technology, Bangkok, Thailand."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1109\/TNSRE.2008.2003375","article-title":"A Magneto-Inductive Sensor Based Wireless Tongue-Computer Interface","volume":"16","author":"Huo","year":"2008","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Cheng, J., Okoso, A., Kunze, K., Henze, N., Schmidt, A., Lukowicz, P., and Kise, K. (2014, January 7\u20138). On the Tip of my Tongue\u2014A Non-Invasive Pressure-Based Tongue Interface. Proceedings of the 5th Augmented Human International Conference, Kobe, Japan.","DOI":"10.1145\/2582051.2582063"},{"key":"ref_10","unstructured":"Zhang, Q., Gollakota, S., Taskar, B., and Rao, R.P.N. (May, January 26). Non-Intrusive Tongue Machine Interface. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, Toronto, ON, Canada."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Nakatani, S., Araki, N., and Konishi, Y. (2015, January 9\u201312). Tongue-motion Classification Using Intraoral, Electromyography for a Tongue\u2013computer Interface. Proceedings of the 2015 IEEE International Conference on Systems, Man, and Cybernetics, Kowloon, Hong Kong, China.","DOI":"10.1109\/SMC.2015.411"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Saponas, T.S., Kelly, D., Parviz, B.A., and Tan, D.S. (2009, January 4\u20137). Optically Sensing Tongue Gestures for Computer Input. Proceedings of the 22nd annual ACM symposium on User interface software and technology, Victoria, BC, Canada.","DOI":"10.1145\/1622176.1622209"},{"key":"ref_13","unstructured":"Kajikawa, S., Takahashi, K., and Mihara, A. (October, January 28). A joystick interface for tongue operation with adjustable reaction force feedback. Proceedings of the International Conference on Intelligent Robots and Systems (IROS), Hamburg, Germany."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Slyper, R., Lehman, J., Forlizzi, J., and Hodgins, J. (2011, January 16\u201319). A Tongue Input Device for Creating Conversations. Proceedings of the 24th annual ACM Symposium on User Interface Software and Technology, Santa Barbara, CA, USA.","DOI":"10.1145\/2047196.2047210"},{"key":"ref_15","unstructured":"Vaidyanathan, R., Kook, H., Gupta, L., and West, J. (2004, January 17\u201321). Parametric and non-parametric signal analysis for mapping air flow in the ear-canal to tongue movements: a new strategy for hands-free human-machine interfaces. Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, Montreal, QC, Canada."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1109\/TSMCA.2007.897919","article-title":"Tongue-Movement Communication and Control Concept for Hands-Free Human\u2013Machine Interfaces","volume":"37","author":"Vaidyanathan","year":"2007","journal-title":"IEEE Trans. Syst. Man Cybern. Part A: Syst. Hum."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Vaidyanathan, R., and James, C.J. (2007, January 23\u201326). Independent Component Analysis for Extraction of Critical Features from Tongue Movement Ear Pressure Signals. Proceedings of the 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Lyon, France.","DOI":"10.1109\/IEMBS.2007.4353586"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/3\/733\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:57:03Z","timestamp":1760194623000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/3\/733"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,3,1]]},"references-count":17,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2018,3]]}},"alternative-id":["s18030733"],"URL":"https:\/\/doi.org\/10.3390\/s18030733","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,3,1]]}}}