This design resulted from the need for a replacement of the drop sensor in an old vending machine which is no longer in production and therefore hardly obtainable. The replacement is a homemade module ...

The piezo disc sensor head (see above circuit) will keep A0 of Arduino at 0 V until it’s disturbed. Once the hardware setup is completed, upload the code, and hit the sensor head with your finger. In ...

We modified a pressure sensor that offered 100-psi range with temperature compensation up to 60°C by removing the top casing and connecting a thin pair of leads across one piezo-resistive element ...