gas sensor wristband 3d model

We propose a disposable silicone wristband that acts as a passive H₂S cumulative dosimeter. The wristband contains an encapsulated sensing chamber. A porous gas-permeable membrane allows H₂S from the surrounding environment to enter the chamber while keeping the sensing chemistry isolated from the user's skin. Inside the chamber, a bismuth nitrate-based sensing layer is investigated as the H₂S indicator. H₂S reacts with bismuth species to form dark bismuth sulfide (Bi₂S2): 2Bi³+ + 3H₂S→ Bi2S2 + 6H+ As exposure accumulates, the sensing layer is intended to progressively change from light to darker shades rather than simply turning completely black at one threshold. Dosimetry Principle The objective is to estimate cumulative H₂S exposure, not only instantaneous concentration. Cumulative exposure ≈ concentration x exposure time The intended output is an estimated value in ppm-h.