In this Pressure sensor circuit we are going to use Piezo element as sensor. Because we need to obtain an electric signal from a mechanic signal or force. You might have seen circuits where digital output switches states depends on threshold pressure. But here in this circuit based on the input pressure Output voltage varies. Therefore the results will be Analog in nature rather than usual digital ones.
COMPONENTS REQUIRED:
Piezoelectric transducer element
Resistor 10 M Ohm, 1 M Ohm and 1.5 M Ohm
Capacitor 25 uF
Op-Amp, LT1464 or similar
12v & 6v power source
WORKING OF PRESSURE SENSOR CIRCUIT:
The working of this circuit starts with Piezoelectric transducer element which is used as Pressure sensing element in our circuit. Piezo sensors generate voltage when pressure is applied on its surface. When there’s no pressure input applied to the Piezo element the output will be 1/2 Vcc. But when you apply force over the sensor the piezo generates voltage across its terminals. This generated voltage will cause a change of the differential voltage input across the Inverting and Non-inverting pins of Opamp.
The differential voltage input force the output to change from from 1/2Vcc up to Vcc. So we should use a Vcc of 12v in the place where it is marked as Vcc in the circuit and 1/2 Vcc that is 6v in the point where it marked as 1/2 Vcc. As the force varies on the sensor output voltage varies in Analog manner. From 6v to 12v, when is no force applied on the sensor output of opamp reads 6v and a moderate force will force the output to be from 6v to 9v ( approximately ). High force will make the output to read from 9v to 12v maximum ( approximately ).
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