Date Presented 04/21/2023

Light and sound measurements were collected to determine whether accessibility results varied across devices as a result of new hardware. The results displayed differences in the data and indicated that algorithms in apps need to be adjusted to account for this.

Primary Author and Speaker: Mason A. D. Drake

Additional Authors and Speakers: Roger O. Smith

Contributing Authors: Sayeda Farzana Aktar

PURPOSE: The purpose of this study was to determine if the differences in iOS version hardware affect the reliability of the AccessLight and AccessSound apps, which can be used by occupational therapy practitioners to collect accessibility measurements (Kardous et al., 2014; Jonhson et al., 2015). These quantifiable measurements assess whether an environment is accessible for clients based on their specific needs (Smith et al., 2019).

DESIGN: The research design was a device reliability assessment that collected quantitative measurements from different iOS devices, light and sound meters.

METHOD: Quantitative accessibility measurements were taken for light and sound. Light measurements utilized four different light bulbs representing different types of light. The lights were used on two light meters and an iOS device at five different heights to account for light intensity. Sound measurements were collected by administering a tone through a speaker suspended above iOS devices and sound meters. Results were recorded at 10% increments across 10 different frequencies.

RESULTS: A total of 825 light measurements were taken from 11 different devices and 3,800 sound measurements were taken from 15 different iOS devices that represented 3 different microphone categories. Results for both light and sound demonstrated variation.

CONCLUSION: Variation among the results indicate there are inconsistencies in the reliability of the accessibility measurements due to the different hardware used in the various versions of iOS devices. This led researchers to conclude algorithm adjustments are needed in the AccessLight and AccessSound apps to account for this variation and provides clinicians with reliable results.


Kardous, C.A. & Shaw, P.B. (2014). Evaluation of smartphone sound measurement applications. The Journal of the Acoustical Society of America, 135(4).

Johnson, N., Saxena, P., Williams, D., Bangole, O.C., Hasan, K., Ahmed, S.I., Smith, R.O., & Tomashek, D. (2015). Smartphone-based light and sound intensity calculation application for accessibility measurement. Poster session at the RESNA 38th International Conference on Technology and Disability: Research, Design, Practice and Policy. Denver, CO. Retrieved from

Smith, R.O., Tomashek, D., & Wilson, C. (2019). Perspectives on Building Accessibility: Survey responses by people with disabilities on accessibility experiences and the need for information. Poster session at the Rehabilitation Engineering and Assistive Technology Society of North America (RESNA) Annual Conference. Toronto, Canada. Retrieved from