Low-cost Sensor Tape for Environmental Sensing Based on Roll-to-roll Manufacturing Process

We describe the concept of fabricating low-cost sensor tape for fine-grid environmental sensing based on roll-to-roll manufacturing processes. We experiment with constructing sensors and electronic connections with low-cost conductive inkjet printed copper traces. Our first attempt is to fabricate humidity sensors by spin-coating conductive polymer on sensor substrates and integrating the design with an embedded system. The humidity sensor was tested in a two-point probe and exhibits the I-V profile of a diode. We demonstrated a working humidity sensor with an impedance variance of 30 k Omega from 99% to 58% RH within 300 seconds under a 1.4 volt bias.