Modulated Pencil-Drawn U-Shaped Piezoresistive Graphite on Compound Fibers for Wind Sensing

Abstract

The design, fabrication, analysis and measurement of the modulated pencil-drawn U-shaped piezoresistive graphite on paper compound fibers and its application for wind speed sensing are reported. We found that pencil drawing was a facile method for producing an ultrafine graphite film through the friction between the pencil leads and paper fibers. The pencil-drawn graphite was characterized by Raman spectroscopy and x-ray diffraction. The resistance of the patterned graphite sensor showed a decrease or an increase due to compression or tension bending, respectively, of the paper cantilever substrate. The wind impacting onto the flexible paper substrate with negative and positive speeds resulted in a bending compression or tension that was related to the resistance measured from the sensor. It was demonstrated that the resistance of a 10-mm -ide line of the U-shaped graphite on the paper substrate was 24k at approximate to 40 degrees and 45k at approximate to-40 degrees. Furthermore, we found that the graphite patterned on paper substrate with a small line width, such as 3mm, showed good linearity for the relationship between the measured resistance and the wind speed.