A Preliminary Study on a Voided Volume Measuring Method Using Noncontact Temperature Sensors under the Toilet Seat

Abstract

Some systems to measure voided volume and ow rate have been developed. Clinically, urination parameters are measured using uro owmeters that have special receivers such as cups or bowls. Since these uro owmeters were developed for clinical use, home use is dif cult and inconvenient. Many of these devices require equipment cleaning; additionally, most are too expensive for home use. To address these problems, we developed a method to measure voided volume by noncontact matrix temperature sensors that are installed under a toilet seat. The basic concept is as follows. Urine is excreted at core temperature of 37 C. The heat radiated from urine during excretion is measured by noncontact matrix temperature sensors, and the measured radiated heat is converted to urination volume. A preliminary study was conducted to estimate the voided volume using an actual toilet bowl. The noncontact matrix temperature sensors simultaneously measure the temperature of falling water at 37 C in 16 areas using a matrix of four lines and four rows. Four noncontact matrix temperature sensors were installed at the front, rear, left and right of the underside of a toilet seat. The toilet seat equipped with the four sensors was installed on a toilet bowl. The position of the falling water was xed at 120 mm from the front sensor. Water volumes of 100, 200 and 300 ml were passed vertically at ow rates of 10, 20, 30 and 40 ml/s. As a result, the surface of the toilet bowl was slightly heated from the heat of the falling water, and the toilet bowl retained the heat after the water had fallen. To eliminate overestimation of heat from the toilet bowl, we proposed two analytical methods: a bias temperature elimination method and a time limitation method. For all four ow rates, the variation of U with a proportional volume obtained by the time limitation method was smaller than that by the bias temperature elimination method.

Personal Identification Using a Ballistocardiogram During Urination Obtained from a Toilet Seat

“…The EER indicates the probability of obtaining a false identi cation result. We obtained voided volume [2] and toilet seat ECGs [11,12] during urination. The voided volume was approximately constant for each subject (Fig.…”

“…With these issues in mind, devices that can be tted to a regular toilet have been developed, and these can automatically record physiological information in a user s daily life. For example, previous studies have reported a system that measured blood pressure through a toilet seat [1], a system that measured voided volume without contacting urine [2], and a system that measured urine concentrations [3]. As these systems automatically measure physiological information, they do not require any additional action on the part of the toilet user, and they can collect data over an extended period of time.…”

Reagentless Estimation of Urea and Creatinine Concentrations Using Near-Infrared Spectroscopy for Spot Urine Test of Urea-to-Creatinine Ratio

“…Sixth, because the experiment was performed with only spot urine samples, the results obtained cannot be compared with other studies performed using 24-h urine samples. However, Fujita et al [27][28] studied urine volume estimation using a noncontact method in the toilet. When this method for urine volume estimation is established, approximate daily urine volume can be estimated from one urine volume, and we may obtain the equivalent data of 24-h urine from spot urine samples.…”

Distinction of Urination or Defecation Using a Gas Sensor Placed Under the Toilet Seat

“…With the possibility of easily acquiring excretion information even at home, the burden on the subject is reduced, and it is possible to automatically acquire excretion information over long periods of time. We developed an excretion monitoring system equipped with non-contact temperature sensor installed under a toilet seat [1]. Subjects sometimes defecate when voided urine volume is measured.…”

“…In the excretion monitoring system, non-contact temperature sensors measure the ow rate of excretion. The principle of this method was reported previously [1].…”