{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:06:21Z","timestamp":1787029581413,"version":"build-2736575974"},"reference-count":40,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T00:00:00Z","timestamp":1624233600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006280","name":"Ministerio de Ciencia y Tecnolog\u00eda","doi-asserted-by":"publisher","award":["DPI2017-90002-R"],"award-info":[{"award-number":["DPI2017-90002-R"]}],"id":[{"id":"10.13039\/501100006280","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>To achieve optimal mobility, visually impaired people have to deal with obstacle detection and avoidance challenges. Aside from the broadly adopted white cane, electronic aids have been developed. However, available electronic devices are not extensively used due to their complexity and price. As an effort to improve the existing ones, this work presents the design of a low-cost aid for blind people. A standard low-cost HC-SRF04 ultrasonic range is modified by adding phase modulation in the ultrasonic pulses, allowing it to detect the origin of emission, thus discriminating if the echo pulses come from the same device and avoiding false echoes due to interference from other sources. This improves accuracy and security in areas where different ultrasonic sensors are working simultaneously. The final device, based on users and trainers feedback for the design, works with the user\u2019s own mobile phone, easing utilization and lowering manufacturing costs. The device was tested with a set of twenty blind persons carrying out a travel experiment and satisfaction survey. The main results showed a change in total involuntary contacts with unknown obstacles and high user satisfaction. Hence, we conclude that the device can fill a gap in the mobility aids and reduce feelings of insecurity amongst the blind.<\/jats:p>","DOI":"10.3390\/s21124250","type":"journal-article","created":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T13:29:58Z","timestamp":1624282198000},"page":"4250","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Low-Cost Ultrasonic Range Improvements for an Assistive Device"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2521-1627","authenticated-orcid":false,"given":"David","family":"Abreu","sequence":"first","affiliation":[{"name":"Departamento de Ingenier\u00eda Inform\u00e1tica y Sistemas, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Spain"},{"name":"Ataman Science S.L.U., 38290 El Rosario, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2789-4799","authenticated-orcid":false,"given":"Jonay","family":"Toledo","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda Inform\u00e1tica y Sistemas, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7021-4130","authenticated-orcid":false,"given":"Benito","family":"Codina","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda Inform\u00e1tica y Sistemas, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6755-5284","authenticated-orcid":false,"given":"Arminda","family":"Su\u00e1rez","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda Inform\u00e1tica y Sistemas, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,21]]},"reference":[{"key":"ref_1","unstructured":"World Healh Organization (2010). Global Data on Visual Impairments, World Healh Organization."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Dandona, L., and Dandona, R. (2006). Revision of visual impairment definitions in the International Statistical Classification of Diseases. BMC Med., 4.","DOI":"10.1186\/1741-7015-4-7"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/j.ajo.2003.08.003","article-title":"The determinants of participation in activities of daily living in people with impaired vision","volume":"137","author":"Lamoureux","year":"2004","journal-title":"Am. J. Ophthalmol."},{"key":"ref_4","unstructured":"Hill, E.W., and Ponder, P. (1976). Orientation and Mobility Techniques: A Guide for the Practitioner, American Foundation for the Blind."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Dunai, L., Fajarnes, G.P., Praderas, V.S., Garcia, B.D., and Lengua, I.L. (2010, January 7\u201310). Real-time assistance prototype\u2014A new navigation aid for blind people. Proceedings of the IECON 2010\u201436th Annual Conference on IEEE Industrial Electronics Society, Glendale, CA, USA.","DOI":"10.1109\/IECON.2010.5675535"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1177\/0145482X8908300907","article-title":"Results of a national survey of electronic travel aid use","volume":"83","author":"Blasch","year":"1989","journal-title":"J. Vis. Impair. Blind."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Dunai, L.D., Lengua, I.L., Tortajada, I., and Simon, F.B. (2014, January 24). Obstacle detectors for visually impaired people. Proceedings of the 2014 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), Bram, Romania.","DOI":"10.1109\/OPTIM.2014.6850903"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Elmannai, W., and Elleithy, K. (2017). Sensor-Based Assistive Devices for Visually-Impaired People: Current Status, Challenges, and Future Directions. Sensors, 17.","DOI":"10.3390\/s17030565"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1109\/TSMCC.2009.2021255","article-title":"Wearable Obstacle Avoidance Electronic Travel Aids for Blind: A Survey","volume":"40","author":"Dakopoulos","year":"2010","journal-title":"IEEE Trans. Syst. Man Cybern. Part C"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Abreu, D., Codina, B., Toledo, J., and Su\u00e1rez, A. (2020). Validation of an eBAT as a mobility aid for blind people. Assist. Technol.","DOI":"10.1080\/10400435.2020.1743380"},{"key":"ref_11","unstructured":"Phillips, G. (2021, June 21). The Miniguide Ultrasonic Mobility aid. In GDP Research, South Australia. Available online: http:\/\/www.gdp-research.com.au\/minig_1.htm."},{"key":"ref_12","first-page":"23114","article-title":"iSonar: An obstacle warning device for the totally blind","volume":"2","author":"Vorapatratorn","year":"2014","journal-title":"J. Assist. Rehabil. Ther. Technol."},{"key":"ref_13","first-page":"3435","article-title":"Smart walking stick for visually impaired","volume":"3","author":"Gayathri","year":"2014","journal-title":"Int. J. Eng. Comput. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1109\/TNSRE.2018.2800665","article-title":"Safe Local Navigation for Visually Impaired Users With a Time-of-Flight and Haptic Feedback Device","volume":"26","author":"Katzschmann","year":"2018","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Ramadhan, A. (2018). Wearable Smart System for Visually Impaired People. Sensors, 18.","DOI":"10.3390\/s18030843"},{"key":"ref_16","first-page":"37","article-title":"Low vision assistive technology device usage and importance in daily occupations","volume":"39","author":"Fok","year":"2011","journal-title":"Work J. Prev. Assess. Rehabil."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Li, M., and Kim, Y.T. (2018). Feasibility Analysis on the Use of Ultrasonic Communications for Body Sensor Networks. Sensors, 18.","DOI":"10.3390\/s18124496"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Yi, D., Jin, H., Kim, M.C., and Kim, S.C. (2020). An Ultrasonic Object Detection Applying the ID Based on Spread Spectrum Technique for a Vehicle. Sensors, 20.","DOI":"10.3390\/s20020414"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"086801","DOI":"10.1088\/0034-4885\/76\/8\/086801","article-title":"Geodetic imaging with airborne LiDAR: The Earth\u2019s surface revealed","volume":"76","author":"Glennie","year":"2013","journal-title":"Rep. Prog. Phys."},{"key":"ref_20","unstructured":"Freaks, E. (2021, June 20). Ultrasonic Ranging Module HC-SR04. Available online: https:\/\/cdn.sparkfun.com\/datasheets\/Sensors\/Proximity\/HCSR04.pdf."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"EL52","DOI":"10.1121\/1.2761883","article-title":"Hearing thresholds for pure tones above 16 kHz","volume":"122","author":"Ashihara","year":"2007","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1037\/0735-7044.97.2.310","article-title":"Hearing in large and small dogs: Absolute thresholds and size of the tympanic membrane","volume":"97","author":"Heffner","year":"1983","journal-title":"Behav. Neurosci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1109\/19.126639","article-title":"Digital time-of-flight measurement for ultrasonic sensors","volume":"41","author":"Marioli","year":"1992","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"526","DOI":"10.1016\/j.sna.2006.02.025","article-title":"High accuracy ultrasonic air temperature measurement using multi-frequency continuous wave","volume":"132","author":"Tsai","year":"2006","journal-title":"Sens. Actuators A"},{"key":"ref_25","unstructured":"Zuckerwar, A.J. (2002). Handbook of the Speed of Sound in Real Gases, Academic Press."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1214\/aos\/1176346577","article-title":"The Dip Test of Unimodality","volume":"13","author":"Hartigan","year":"1985","journal-title":"Ann. Statist."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1016\/j.sna.2013.06.028","article-title":"A new hybrid infrared-ultrasonic electronic travel aids for blind people","volume":"201","author":"Prattico","year":"2013","journal-title":"Sens. Actuators A"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1080\/00031305.1978.10479236","article-title":"Variations of Box Plots","volume":"32","author":"Mcgill","year":"1978","journal-title":"Am. Stat."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Mocanu, B., Tapu, R., and Zaharia, T. (2016). When Ultrasonic Sensors and Computer Vision Join Forces for Efficient Obstacle Detection and Recognition. Sensors, 16.","DOI":"10.3390\/s16111807"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1016\/j.apergo.2013.10.012","article-title":"Assessment of a simple obstacle detection device for the visually impaired","volume":"45","author":"Lee","year":"2014","journal-title":"Appl. Ergon."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Kim, K., and Choi, H. (2021). A New Approach to Power Efficiency Improvement of Ultrasonic Transmitters via a Dynamic Bias Technique. Sensors, 21.","DOI":"10.3390\/s21082795"},{"key":"ref_32","unstructured":"Fryar, C.D., Gu, Q., and Ogden, C.L. (2021, June 20). Anthropometric Reference Data for Children and Adults; United States, 2007\u20132010. Available online: https:\/\/stacks.cdc.gov\/view\/cdc\/12223."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1080\/10400435.2012.659794","article-title":"User Evaluation of Two Electronic Mobility Aids for Persons Who Are Visually Impaired: A Quasi-Experimental Study Using a Standardized Mobility Course","volume":"24","author":"Roentgen","year":"2012","journal-title":"Assist. Technol."},{"key":"ref_34","unstructured":"Morris, M.H., and Morris, G. (1990). Market-Oriented Pricing: Strategies for Management, Greenwood Press."},{"key":"ref_35","unstructured":"DiResta, R., Forrest, B., and Vinyard, R. (2015). The Hardware Startup: Building Your Product, Business, and Brand, O\u2019Reilly Media, Inc."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1518\/001872008X250638","article-title":"Tactile Displays: Guidance for Their Design and Application","volume":"50","author":"Jones","year":"2008","journal-title":"Hum. Factors"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Karuei, I., MacLean, K.E., Foley-Fisher, Z., MacKenzie, R., Koch, S., and El-Zohairy, M. Detecting Vibrations Across the Body in Mobile Contexts. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, Vancouver, BC, Canada, 7\u201312 May 2011.","DOI":"10.1145\/1978942.1979426"},{"key":"ref_38","first-page":"28","article-title":"The generalization of \u2018Student\u2019s\u2019 problem when several different population variances are involved","volume":"34","author":"Welch","year":"1947","journal-title":"Biometrika"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1136\/bmj.314.7080.572","article-title":"Statistics notes: Cronbach\u2019s alpha","volume":"314","author":"Bland","year":"1997","journal-title":"BMJ"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1098\/rspl.1895.0041","article-title":"Note on Regression and Inheritance in the Case of Two Parents","volume":"58","author":"Pearson","year":"1895","journal-title":"Proc. R. Soc. Lond."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/12\/4250\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:20:28Z","timestamp":1760163628000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/12\/4250"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,6,21]]},"references-count":40,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2021,6]]}},"alternative-id":["s21124250"],"URL":"https:\/\/doi.org\/10.3390\/s21124250","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,6,21]]}}}