Figure 3 - available via license: Creative Commons Attribution 4.0 International
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Algorithm for sensor signal processing. (a) Raw signals collected from the photometric sensor and the pressure sensor. (b) Baseline-subtracted optical signal and inhalation pressure. (c) Determination of the puff duration with a threshold on the optical signal. (d) Calculation of the numerical integral of S(t) ∆P(t) during the identified puff.
Source publication
To study and monitor the adverse health consequences from using electronic cigarettes, a user’s puff topography, which are quantification parameters of the user’s vaping habits, plays a central role. In this work, we introduce a topography sensor to measure the mass of total particulate matter generated in every puff and to estimate the nicotine yi...
Contexts in source publication
Context 1
... in this work, only the near-infrared wavelength is used. Figure 3a shows one raw optical signal, S raw (t), acquired from the sensor when testing the smart e-cigarette with the vaping machine. The data sampling rate of the optical signal is 50 Hz, and the sampling interval is 20 ms, which is sufficient to resolve the rising and falling optical signal triggered by the generated e-cigarette aerosol. ...
Context 2
... duration is much longer than the practical puff duration of a regular e-cigarette puff, however, it is necessary for the purpose of synchronizing data acquisition sequence of the e-cig topography sensor with the control sequence of the vaping machine. At the beginning of the raw optical signal, there was no e-cigarette aerosol, and the baseline signal, S base , was calculated by the average of S raw (t) during the window between t = 5 sec and t = 10 sec (marked on Figure 3a). The actual optical signal, S(t), shown in Figure 3b, was calculated by subtracting the baseline signal from the raw signal, i.e. ...
Context 3
... the beginning of the raw optical signal, there was no e-cigarette aerosol, and the baseline signal, S base , was calculated by the average of S raw (t) during the window between t = 5 sec and t = 10 sec (marked on Figure 3a). The actual optical signal, S(t), shown in Figure 3b, was calculated by subtracting the baseline signal from the raw signal, i.e. S(t) = S raw (t) − S base , in order to correct the sensor's response to zero aerosol. ...
Context 4
... the signal from the pressure sensor, P(t), is also plotted in Figure 3a. The BME680 detects the air pressure through piezoresistors which can measure the mechanical stress or strain induced by a membrane displaced by the applied air pressure. ...
Context 5
... negative pressure can be clearly observed when the aerosol is being drawn out of the device. The ambient pressure, P amb was calculated by the average of P(t) during the window between t = 50 sec and t = 55 sec (marked on Figure 3a) after the pressure has reached the stable ambient pressure after the puff. The inhalation pressure, ∆P(t), calculated as ∆P(t) = P amb − P(t), is plotted in Figure 3b. ...
Context 6
... ambient pressure, P amb was calculated by the average of P(t) during the window between t = 50 sec and t = 55 sec (marked on Figure 3a) after the pressure has reached the stable ambient pressure after the puff. The inhalation pressure, ∆P(t), calculated as ∆P(t) = P amb − P(t), is plotted in Figure 3b. ...
Context 7
... e-cigarette aerosol is detected only when S(t) is above a threshold, as illustrated in the magnified view of signals in Figure 3c. In this work, a threshold of 300 is applied in all signal processing. ...
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Background Electronic cigarettes are a mass consumption product with great market penetration, particularly among groups of young adults. Recently, attention has been drawn to the increasingly frequent reports of cases with vaping-related disease, leading to hospitalizations and death. Methods An ecological study was designed to characterize the us...
