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Grove - Water Sensor detects the presence of water using exposed PCB traces. The sensor is made up of interlaced traces of Ground and Sensor signals. The sensor traces are weakly pulled up using 1 MΩ resistor. The resistor will pull the sensor trace value high until a drop of water shorts the sensor trace to the ground trace. This circuit will work with digital I/O pins of Arduino or you can use it with the analog pins to detect the amount of water induced contact between the grounded and sensor traces.
For all Grove users (especially beginners), we provide you guidance PDF documents. Please download and read through Preface - Getting Started and Introduction to Grove before your using of the product.
Please visit our wiki page for more info about this product. It will be appreciated if you can help us improve the documents, add more demo code or tutorials. For technical support, please post your questions to our forum.