A cantilever operated vibrating thin strip for sensing pneumatic pressure

This paper proposes a pneumatic pressure sensor along with a microprocessor-based signal processing and indicating instrument. A thin strip in the form of a cantilever is attached to a diaphragm facing a pneumatic medium on other side. The strip traverses through a pivoted hinge whenever pressure on the diaphragm is changing. The microprocessor excites the strip for producing mechanical oscillations, through an electromagnet and reads the oscillations of the strip from an optocoupler. The fundamental frequency of vibration is then estimated by software. As the frequency of oscillation depends on the length of the strip extending beyond the hinge, the microprocessor determines the instantaneous length of the strip and the pressure acting on the diaphragm, from the frequency measured. The proposed instrument has more sensitivity compared to the conventional pressure meters. Also, this has more durability compared to the previous vibrating wire transducer