Inkjet printing of multi-stripes based deflection monitoring sensor on flexible substrate

This work presents an interesting approach towards rapid manufacturing of multi-stripes based deflection sensors developed through printing technologies. The deflection sensor is made of multiple small-scale strain sensing stripes sandwiched between consecutive conducting stripes. The drop-on-demand inkjet printing is used to pattern silver (Ag) nanoparticles ink as conducting interconnects and metallic stripes, whereas the piezoresistive sensing layer is obtained by mixing powdered carbon black and MWNTs in PDMS base matrix, resulting into a conducting nanocomposite. Different physical, optical, electrical, and adhesion-loss tests were performed as evaluation of the printing experiments. Deflection sensing was evaluated by mounting the sensors on opening cover-head of a plastic box to monitor different opening angles. Four detection angles at 0°, 10°, 45° and 90° were evaluated, for which the sensor showed prominent response at each level. The plastic box was used to represent the fill levels of a waste collection bin. The sensors will be advanced further by making an array of sensors where other parameters such as temperature, humidity, and concentration of the VOCs can also be monitored. All these advancements will be headed towards smart waste collection that is an integral part of Smart Cities development as well as internet-of-things (IoT) applications.