Development of an Al-load-cell-based wireless ringer’s solution monitoring and alarm system: insight into vibrational error correction

• Published in: Biomedical engineering letters Vol. 9; no. 2; pp. 245 - 255
• Main Authors: Moon, Hyun Seok, Jang, Eue-Soon
• Format: Journal Article
• Language: English
• Published: Korea The Korean Society of Medical and Biological Engineering 01.05.2019; Springer Nature B.V; 대한의용생체공학회
• Subjects: Alarm systems; Algorithms; Aluminum; Biological and Medical Physics; Biomedical Engineering and Bioengineering; Biomedicine; Biophysics; Engineering; Error analysis; Error correction; Load cells; Medical and Radiation Physics; Original; Original Article; Standard deviation; Strain gauges; Vibration monitoring; Vibrations; Weight reduction; Wheatstone bridges; 의공학; Modal analysis; Static analysis; Harmonic analysis; Wireless Ringer’s solution monitoring and alarm system; Vibrational error; Al load cell; Wheatstone bridge
• ISSN: 2093-9868; 2093-985X
• DOI: 10.1007/s13534-019-00107-x

In this study, we developed an aluminum-load-cell-based wireless Ringer’s solution monitoring and alarm (WRMA) system. The Al load cell was designed with a rectangular shape, and the load was concentrated in the lower beam part of the load cell because of the anisotropic thickness. From the static analysis, we identified the appropriate location for a Wheatstone bridge circuit consisting of four strain gauges. In addition, the modal and harmonic analyses showed that the vibrational frequencies of the hospital environment do not seriously interfere with the output voltage of the Al load cell. However, random vibrations generated by the movement of the WRMA system on various surfaces severely increase the standard deviation of the measured solution weight by ± 10 g or more. Such vibrational error is too large because the average weight of Ringer’s solution is 30–40 g at the time of replacing Ringer’s solution. Thus, this error could be confusing for nurses and result in mistakes in the timely replacement of the Ringer’s solution. However, the standard deviation of the measured weight was dramatically reduced to ± 3 g or less by using the vibration correction algorithm developed in the present study.