Portable ZnO-based ammonia detector for continuous monitoring in poultry industry

A portable continuous ammonia detecting device using nanostructured zinc oxide (ZnO) as a chemiresistive element is demonstrated in this work. Nanostructured ZnO was deposited on a commercially available ceramic tube with 5 mm length and outer diameter of 1 mm by spray pyrolysis technique at 350°C. The X-ray diffraction studies of ZnO showed the polycrystalline nature with multiple peaks. The morphological studies confirmed the uniform distribution of nanostructure over the entire surface of the tube. The ZnO crystal planes observed in the selected area electron diffraction pattern matched with the X-ray diffraction pattern. Since ZnO offers very high resistance, it was interfaced with operational amplifier TLC272CP with a gain of 13. The sensing module’s response to various concentrations of ammonia at elevated temperatures was studied. The selectivity of the sensing module towards major farm field and poultry gases were also investigated. Further, the sensing module was integrated with Arduino Uno R3 and thin film transistor display to show the continuous variation of ammonia concentration in poultry and farm fields. The estimated range of detection of the continuous ammonia detecting device was found to be 5–100 ppm.