The sensitivity of two commercial metal oxide (MOx) sensors to ethylene is tested at different relative humidities. One sensor (MiCS-5914) is based on tungsten oxide, the other (MQ-3) on tin oxide. Both sensors were found to be sensitive to ethylene concentrations down to 10 ppm. Both sensors have significant response times; however, the tungsten sensor is the faster one. Sensor models are developed that predict the concentration of ethylene given the sensor output and the relative humidity. The MQ-3 sensor model achieves an accuracy of ±9.2 ppm and the MiCS-5914 sensor model predicts concentration to ±7.0 ppm. Both sensors are more accurate for concentrations below 50 ppm, achieving ±6.7 ppm (MQ-3) and 5.7 ppm (MiCS-5914).

A rapid advanced packaging concept, consisting of inkjet photopolymer printing and Ag nanoparticles printing, was investigated for the construction of a pressure sensor package. Acrylate-type 3D package housing with 7 through-holes was printed with a polyjet printer and the through-vias and connection pads were manufactured via Ag glue dispensing and inkjet printing of Ag nanoparticle ink. The flip-chip packaging concept was pursued for the electrical connection between the package and the pressure sensor dye.